My last article, which appeared all the way back in the May issue believe it or not (did something happen between then and now? Oh yes…), was a little lesson on wheel alignment. I also covered the issue of minutes and degrees too. This article is about camber angles and setting up wheel alignment.
Camber
The same applies to camber (minutes and degrees) as it did with toe, it’s just a different angle. Now stand up, like you did back in May when I first mentioned toe in and toe out, then asked you to look down at your feet, keep your heels in position, and point your toes inwards so they point towards each other, and then the same with the heels with the toes outwards. This was toe-out, and walking with excessive toe-out, I pointed out, will wear the inner part of your shoes.
I bet you have been looking back on that fondly. Well, it’s time to do it again. Come on, I’ll do it with you. Feet shoulder width apart, and now, try and make your knees touch, your legs now have negative camber. You can now turn into corners quicker. However, I bet you won’t be able to run very fast in a straight line without falling over.
Negative
You will have seen many boy racers with modified cars on the roads that think it’s great to run massive amounts of negative camber, that’s all well and good if they own a racing car and take it on a race track, but on our public roads and with our speed limits, what’s the point? There’s nothing to gain. Your tyres will wear at an alarming rate on the inside edge, and cost you more money, but it looks cool right? So, that’s ok. I’m sorry, did that sound sarcastic?
Now, if you were to stand with your feet in the same position as before, but now move your knees outwards, it’s difficult I know, your legs will be enduring positive camber. This is more stable than your negative legs were, but you wouldn’t want to turn into corners too fast with these legs. No, you would almost certainly fall over and probably break your leg and I would have a lawsuit on my hands. You won’t see many sports cars at all with a positive camber setup, it just wouldn’t work.
That’s why we leave it to the engineers who design the cars to then give us, the technicians the correct wheel alignment settings. just make sure that the alignment is set within the manufacturer’s spec, that way you can’t go wrong.
ADAS
If the car is fitted with a form of ADAS, that’s when things get a little tricky. The company I work for don’t actually make adjustments on vehicles equipped with any form of ADAS, a VERY wise decision I think. Also, any garage that does make adjustments are playing with the driver’s (and the driver’s family’s) lives. It’s all well and good taking £50-£60 from the customer for the alignment, but without correct kit to calibrate the camera and radar afterwards you’re playing very dangerous games.
A car equipped with ADAS is easily identifiable really. The radar box can’t be missed in a front bumper, unless you’re one of those annoying manufacturers who hide it behind the badge. Some cars have a blind spot detection system built into the wing mirrors, identifiable by the letters BLIS/BSW/BSM. The easiest to spot without a doubt is the forward-facing camera at the top of the windscreen close to the rear-view mirror. This is funnel shaped if you understand what I mean. I don’t think ADAS calibration equipment can be that far from being installed in the majority of workshops up and down the country. As soon as the equipment gets to an affordable price, garages will be snapping it up and capitalising on the chance to rake in the money.
I know it’s not all about the money, but at the end of the day that’s why we all go to work, and we as the techs are the ones keeping the money rolling in, but just make sure the money is earned honestly and faithfully. I’d hate to read one day about a car having an accident due to a garage mindlessly taking the customer’s money. If you aren’t sure if a car is equipped with ADAS when carrying out a wheel alignment check, all you need to do is ask a workmate to take a look. Better safe than sorry.
Fig 2
I have always focused on topics that have developed through our workshop, the main reason for this is authenticity and integrity. However, it is not always possible to be fortunate enough to have topics with enough content for publication. So, this month we are going to have a banquet of multiple stories of interest where you can spin the table and pick your favourites.
First topic
An Audi S3 came in for a MIL light and poor running complaints. Initial serial interrogation concluded camshaft correlation errors. This has significant concerns with this 888 power plant, as it has variable inlet and exhaust control as well as exhaust valve lift. This is a very powerful and usually competent engine, but unfortunately the vehicle was purchased recently with a known poor service history. This is an absolute no-no with today’s technology. Having conducted a basic health assessment, and noting actual and specified camshaft position errors, it was decided to replace the oil and filter. I must add here that it ran much worse afterwards.
Historical experience has shown problems with chain jumping and oil filter cartridge collapse. This engine employs a variable displacement oil pump providing 1.8 bar at low speed and 3.8 at higher load. It is also PCM-mapped. I am not a fan of such a low oil pressure especially on crank start. My Seat Cupra has on several occasions displayed slight chain tension noise on start up. Bear in mind I replace the oil every 3,000 miles, and it has only done 18,000 miles.
Additional thoughts should be given to Stop/Start; All engines will suffer gravitational oil drainage when stopped. We are now increasing this multiple times. Not a good idea really. We have also seen oil filters collapse shedding filtration media particles into the oil galleries.
The timing cover was removed, visual evidence shows surface bearing damage to both the cams and alloy cover. This evidence confirms both a boundary layer lubrication failure and metallic swarf erosion. In my opinion this is sufficient evidence to reject the entire engine, subject to a total strip-down. Please refer to; Fig.1, cam sprocket and chain; Fig.2 cover housing; Fig.3 Parts assembly.
The vehicle is still enjoying an elevated position awaiting my report for the insurance company, which requested to know what caused the problem.
I have penned many reports and have prevailed in all my expert witness cases, and smell another one here, or it could be the beef noodles and bean sprouts?
Second topic
Next, we have an AUDI A6 2.7 CRD presented to us as a trade-in into a Vauxhall dealership. The problem is that it is cranking with intermittent no-start. Initial checks were carried out showing a DTC, ground short to power on the in-tank fuel pump relay. I am often amused with this description, as if it was taken literally there would be smoke and probably fire as the loom fuses together rather quickly.
Please refer to Fig.4 relay location r/h. Time to call Diagnostic David. Why the definition? Well, we have three Davids at ADS. Diagnostic David bridged the relay 30-87 terminals in order to run the pump and the vehicle started every time. He then conducted wiring integrity tests between the PCM and pump relay focusing on terminals 86-85. No problems here, power was present from supply right back to the ground control circuit at the PCM. The obvious conclusion an internal PCM ground switch error? This is where you MUST take a pause? Why? Because you have discovered the symptoms NOT the cause. David then exposed the edge connector between the loom and PCM. Please refer to Fig.5; Oil on PCM socket. David elected to expose the board in the PCM and visually check for component damage. Visual evidence shows blister damage to a controller chip suggesting excessive load.
Having discovered oil on the edge connector we now need to prove the cause. So, we are looking for capillary invasion through the loom from a component with access to oil. The usual and obvious components oil switches showed no oil invasion on the sockets.
In fact, the search proved difficult due to limited access. However, David eventually discovered the path of capillary invasion back to #5-injector socket. This engine variant uses piezo injectors, and to my knowledge I have never heard of or experienced this type of problem. The electrical connector is external from any lubricant, so the problem must be internal from within the portion that is exposed to lubricant.
Last month, I was debating the opportunities with non-intrusive diagnostic techniques, and more to the point the reliability of results. I think it is important to accept, as with all skill-based process, the accuracy and results depends very much on experience. A second opportunity presented itself for this topic in the form of an Audi RS3 with a very sick engine.
I’m going to make my thoughts truly clear at this point; I see no point in applying a potentially complex series of tests where simplicity prevails. The Audi RS3 is a prime example of this, with a totally dead cylinder. We must however understand all techniques where cost, accessibility and risk factors demand an evidence-based decision.
With that cleared up let us review and discuss the series of tests carried out. The owner was somewhat vague as to the history of the problem. He explained the problem had been present for some time and hoped he could drive through it. As this topic will later confirm he has driven right into it.
Mechanical resistance
Due to the severity of the misfire, a decision to conduct a relative compression test was sufficient to confirm a serious internal engine defect. David and I were curious to challenge other options to determine the full extent of failure without component removal.
Attaching a current clamp around the ground lead, we were able to compare the mechanical resistance to battery current consumption, this can also be performed with voltage drop or both. The logic here is that all cylinders should balance. This test will not confirm valve timing errors or low compression across all cylinders! However, if you apply the x3.5 rule to the amp/hr battery rating, you should be able to predict the correct work rate and rotation speed, assuming of course you have confirmed correct battery application and health status.
We have no current consumption from cylinder 1 possibilities, problems with valve operation or piston to bore seal. The next test was to attach the first look sensor to the dip stick tube (see Fig.1), with the obvious aim of predicting potential cost and action plan.
So, it about as bad as it gets, the drop in current draw is synchronous with a rise in crankcase pressure rise. Oh dear. Annette did a cost exercise with a new engine replacement and turbo, inclusive of labour with no change from £40,000.
Ultimate techniques
For the purpose of comparing in cylinder compression using WPS and first look in the exhaust we now move on to the ultimate engine internal analysis techniques. My interest here was to compare actual in-cylinder events and exhaust exit pressures in real time to ascertain any delay and if cylinder overlay could be used to confirm which cylinder event was responsible for the result.
I will re-state my opinion here, having spent the first 20 years of my career as a professional engine builder I do not care which cylinder is faulty or what the internal fault is! Why? If I’m going to rebuild the engine, then it’s all coming apart for examination. Professional pride and reputation is priceless, so unfortunately nobody wants to pay for it!
Having fallen of my soap box, I do accept as diagnostic technicians we must provide the customer with a factual and accurate estimate with the quickest low-cost process. apart from the fact I find in cylinder and vibration analysis fascinating.
Important variables
Before discussing the complexity of Fig.2, there are some important variables that affect results, remembering that we are dealing with pressure differential or absolute values otherwise none of this will make sense.
Assuming a good in-cylinder seal, the slower the piston speed, the greater the pressure differential. For example, cranking compression is approximately three times greater than when running at idle. This is because of pumping losses with a closed throttle, the descending piston creates an expanding volume that has more time to draw in a fresh air charge, therefore higher compression.
A weak cylinder will accelerate up the bore quicker due to a drop in resistance, lower compression, and accelerate down the bore as the pumping losses are reduced, lower drag.
The first look sensor in the exhaust will record an increase in pressure drop with a weak cylinder due to the lower initial compression followed by the expansion in volume and corresponding increase in pressure differential when the exhaust valve opens. This causes the classic intake pulse at the tail pipe.
With the scope, green channel, and overlay triggered from cylinder 1 PCM ignition pulse, you can clearly see an extremely poor compression, erratic pressure rises and poor tower symmetry. The exhaust cycle is erratic with poor definition when the inlet valve opens. The expansion and intake voids are poor, also confirming a faulty
cylinder seal.
The first look image, red channel, shows multiple increase in exhaust pressure voids which I find unhelpful. It does not in my opinion add any useful diagnostic value. I’m happy to accept any alternative opinion.
A fault code can tell you a lot, if you understand what it is telling you. Then again, it can also leave you questioning what it means and what is causing it to be set if you don’t know why it has logged in the first place.
A recent job I had backs up the importance of knowing what the information is telling you.
Turbo boost pressure
The vehicle was a 2008 Vauxhall Antara 2.0 Diesel, which belonged to my neighbour Gordon. One evening, having a chat over the fence, he said he had been having running issues. After his local garage plugged into it, they changed some parts based on fault codes they found, but it was no better. The vehicle logged turbo boost pressure fault codes under load, and had slowly got worse and worse to the point it was now as flat as a pancake and had no power at all. I offered to bring some tools home and plug it in and have a quick look one night, and then offer some advice on where to go next as a favour. After all, on several occasions he had helped me out with one thing or another.
Plugging in my Snap-On Zeus, the one that was part of my prize when I won Top Technician 2019, I was presented with the a number of fault codes (see Fig.1). Upon asking some questions, he told me that the vehicle repeatedly logged faults for turbo boost pressure, so the boost pressure sensor (MAP) had been replaced but the vehicle still had the same symptoms. The EGR valve vacuum control solenoid had also been replaced as it had fallen apart, and on removal the old one had signs it had been broken and repaired.
Reviewing the situation, we have six faults stored on initial inspection. What I like to do here is split the faults into groups of what could be related to the customer’s complaint and what can be left for now and diagnosed/repaired further down the line.
Grouping faults
My groups, based on my findings, were that the P0101, P0045, P0069 and P0299 faults were directly related to the lack of power complaint. I also surmised that the fuel level fault and glow plug fault were secondary faults which required attention after the initial four faults had been rectified. After a quick visual inspection under the bonnet, this vehicle was equipped with a DPF so the glow plug fault would require attention sooner rather than later. I decided to leave the fuel fault, as in my experience this wouldn’t cause the customer complaint. However, like everything, there will be cases with certain manufacturers where a similar fault code could cause a running fault. This means it’s always a good idea not to ignore every fault code stored.
With the faults, I wanted to focus so now I broke them down one by one by what they meant and what could cause them to set. This was done with a mix of technical information and my own personal knowledge. My list was as follows;
P0101 – Intake air system leak detected: This fault is logged in relation to the mass air flow sensor and it is because the engine control unit detects that the measured MAF is not within range of the calculated model in the software that is derived from the boost pressure sensor, which remember is new. For this fault I would compare live data from the MAF and MAP to see if either were incorrect.
P0045 – Boost pressure valve low voltage: This fault is logged either by a short to ground in the circuit or an internal fault in the control valve itself. As I wasn’t familiar with the engine, I had a visual inspection to see whether the turbo actuator was electric or was controlled by vacuum, on this engine the control actuator was an electric unit so the fault could indicate an issue with the unit itself internally. I decided again for this fault to use live data as a starting point to see if any data was available for the control unit.
P0069 – Barometric pressure not plausible with boost pressure: This fault is logged when the ECU compares values from both sensors for plausibility and if either are out of spec the code will set. Once again live data to view both sensors reading was to be my first check to see if some direction could be gained.
P0299 – Boost pressure low pressure: This fault is exactly as it states, the ECU isn’t seeing the correct pressure from the MAP sensor it should be. Using multiple inputs from other sensors the ECU knows how much pressure the turbocharger should be creating via the electric actuator and as it is not seeing what it should be the code is set. This code could be caused by the turbocharger itself being faulty, the electric actuator not working correctly or the MAP sensor not reporting the correct pressure back to the ECU. Again, live data would be my first port of call as I could look at possible causes of all four faults codes and there may be a common link causing all four.
Live data
With my list done and my plan ready to execute, I then went into live data to see what the ECU was seeing and gain information to plan my next step. I set up a custom list view and brought up my sensors in question. All MAF, MAP, BARO and Turbo actuator command data PIDs were displayed and reviewed to see if anything stood out. As in my previous articles, knowing what the numbers displayed mean is crucial as if you don’t know, how can you make an accurate diagnosis? So, to keep it very simple for the sake of the length of this article, for MAF I want to see 0 air flow ignition on, engine off which I will refer to as KOEO (key on, engine off) steady flow at idle and increasing flow in relation to engine speed and load. I won’t list numbers as every scan tool lists different air flow measurements but common ones you will see are grams per second (g/s) and kilogram per hour (kg/h).
For BARO I want to see a steady 1 bar under all conditions, KOEO, engine running etc. The main reasons this sensor is fitted is so that the ECU knows the current atmospheric pressure for correct air/fuel mixture for emissions and for plausibility to make sure other sensors are operating correctly. As in the UK we live at near enough to 1 bar atmospheric pressure this sensor should be as close as possible.
For MAP I want to see 1 bar KOEO (plausibility check), then a pressure rise along with engine speed and load. Again, this is where the ECU compares BARO and MAP to each other. If one isn’t correct, it will know and log the P0069 code. This is required as if one drifted out of calibration and read differently but still operated within tolerance, the ECU would determine it to be ok which could cause running issues but no faults to be stored.
For turbo actuator command, I want to see some form of change in command to the turbo again under engine speed and load to make sure something is happening as if there is no movement the turbo will not create any boost pressure.
Observing data, I found the MAF to be reading what I expected under all conditions, and the BARO was correct. However, the turbo actuator control was a fixed value, which is clearly wrong. Was this a turbo issue or something else? The final piece of the puzzle was the MAP reading and KOEO. I had 0 pressure, and knowing we should see 1 bar, I have direction on where to go. Increasing engine speed and load, the pressure did rise slightly but we clearly have an issue. Remember, there is also no turbo control but we have to consider that if the ECU cannot see boost pressure, as a failsafe it won’t actuate the turbo in case it over boosts and causes some form of damage. Again, this reinforces the importance of knowing system operation.
MAP sensor test
With all this data gathered, my next step was to test the MAP sensor. This sensor was new, and through questioning Gordon I learned it was a genuine part, so why didn’t it read correctly? Testing power supply and ground to the sensor, both were ok so onto testing the signal wire. The signal voltage in live data was available and was compared to actual data gently back probing the wire, after checking both they matched exactly. Using my sensor simulator, I applied a varying voltage down the signal wire which matched in live data, so what next? We have a genuine new sensor, good wiring and correct ECU operation it seems? At this point with limited tooling and having had a quick look, bearing in mind it has taken me longer to write the article thus far than actually carry out my testing, I asked permission to arrange to take the vehicle to the workshop to carry out further testing.
With permission from Gordon, a few days later I nursed the poorly vehicle up to the workshop to continue fault finding his vehicle. Out of curiosity I had asked if the old MAP sensor had been kept, which it had, so I brought it with me to test to see if anything could be found. On measuring the new sensor, the signal voltage KOEO was 1.07 volts. As a quick check, I plugged in the old sensor and it read 1.64v so 0.5 volts difference. Bear in mind, for this sensor, this will make a massive difference in pressure conversion by the ECU. Checking live data, I now had my 1 bar pressure I was looking for so the new sensor appeared to be faulty as the voltage for static engine off pressure was too low and the ECU was looking for 1.6v. Starting the engine, the boost pressure barely rose, so I had fixed one fault but we still had another issue and more than likely the initial complaint. Noting faults and clearing them only left p0045 boost pressure valve low voltage. Remember from before when I had no change in position from the control actuator? Well, now I had change, but it was very slight and far less than I expected to see.
Turbo and actuator movement
So where to next? I decided to visually inspect the turbo and its actuator movement with someone increasing engine speed to see what happened. Upon inspection, I found the actuator arm was remaining still but showing signs the actuator was attempting to move, but wasn’t able to. I then decided to check movement of the linkage arm that the actuator moves. On some turbo assemblies, this can be done fully assembled or activated via a scan tool special function, but on this unit the motor was locked and attempting activation didn’t work, possibly due to there being a stored fault code.
This meant the linkage had to be removed from the actuator, Upon removal, the linkage arm and pivot were tight and it took considerable force to move through its full travel so we had found the cause of the fault. The low voltage fault was being logged as the position of the arm wasn’t where the ECU was commanding it to be, and as it stayed where it was (low) a corresponding fault code was set.
After cleaning and lubricating the arm and pivot I managed to get everything free and greased up to prevent a reoccurrence. Once reassembled, I then checked MAP pressure in live data now seen a nice increase in pressure in line with engine speed and could now hear an audible whistle from the turbo indicating it was creating pressure. A long road test monitoring data confirmed correct operation and the vehicle was returned to its owner.
Understanding
This article highlights the importance of understanding what a fault code is telling you, and also why it pays to spend time learning to understand to make an accurate diagnosis. Like everyone, I don’t know the meaning of all fault codes and this is where technical data comes in and plays an important part in diagnosing faults. As for the faulty new map sensor? Well, after some digging it was actually the wrong sensor supplied, even though it fit and plugged in. It was actually for the 2.2 engine which uses a different intake/turbo layout.
As I write this (in April), we had just began our fourth week of lockdown and I am doing just two mornings per week to deal emergency jobs for key workers. Very strange times indeed! However this has given me the opportunity to write up a few more interesting jobs that I’ve done over the past few months. This particular one got me thinking about a few different things and maybe considering tweaking my diagnostic process slightly.
The owner of a garage that we do a bit of diagnostic work for contacted me to ask if I could take a look at a 2015 Ford Fiesta 1.5 TDCi that was causing him grief. The complaint was that shortly after start-up and moving off, the vehicle would drop into limp-home mode with multiple warning lights on the cluster.
As always, I asked some questions to gather as much background information as possible, and so the story began. The vehicle came into their workshop with the above symptoms. The fault codes stored pointed towards a turbo wastegate fault. You’re probably mostly thinking the same as I was at this point; sticking wastegate, wastegate control solenoid malfunctioning, vacuum fault, can’t be that complicated surely?
We discussed all the tests that were carried out and what parts had been replaced. This included a new genuine solenoid valve, an actuator repair kit followed by a reconditioned turbocharger. With the fault still present the turbo supplier then recommended a trip to the nearest franchised dealer for testing and a turbo position sensor relearn. After spending some time on the vehicle, the dealership’s diagnosis was the turbocharger and recommended a genuine replacement unit. Reluctantly the garage fitted a genuine unit but guess what? I don’t need to answer that!
Challenge
The vehicle arrived and I started my plan for diagnosing this fault. I was in challenge mode now and was not prepared to be beaten. I knew my plan had to be thorough so I took some time to confirm the fault and do some research. As tempting as it is, just to clear the fault codes and carry out a fresh test – this isn’t always a good move, particularly when the fault is intermittent and may take some time to replicate. In this instance however, there was little to lose by doing this as apparently the fault was very consistent.
I took a read of the fault codes which were as follows:
For as long as I can remember, the questions arising from presentations to our sector usually involve at least one about hydrogen. This can be seen as an abundant, readily available resource and a solution to long-term electric power generation akin to nuclear fusion, in that in both cases the by-product is harmless.
Pure hydrogen is an important component of many industrial chemical processes, so generation of more hydrogen to feed transportation will add pressure to existing industrial capacity. Hydrogen exists either in association with itself (H3 – which is unstable) or with other atoms (for example water, H2O – which is stable). It also exists inside many, many organic compounds, but effectively is not available in nature as a pure gas.
Pure hydrogen can be manufactured from coal, oxidation of methane or steam reforming of methane. Methane is a principle component of natural gas, so there is a plentiful supply of raw material. Most of the pure hydrogen available for use today is made by one of these industrial processes, which all require energy to effectively extract the hydrogen and then more energy to compress it to the point the gas liquifies.
Hydrogen can also be extracted by passing electricity through water, and there have been many aftermarket kits that do exactly this to generate a form of hydrogen peroxide which is then ducted into an internal combustion engine intake system to offset the hydrocarbon fuel burn rate. However, if we need to generate pure hydrogen on a scale to develop transport, this process needs to be upscaled.
The conclusion: Pure hydrogen prefers to be attached to other atoms to achieve stability, and if we need to extract it requires is an energy investment. Further, the most common source of pure hydrogen is from natural gas, where the by-products are carbon dioxide and carbon monoxide. Hardly right-on.
The application
Let’s skip eco-obstacles. What can we do with it?
There are essentially two routes to use hydrogen. Some manufacturers openly experimented with hydrogen as a fuel for internal combustion engines.
Mazda built several Wankel engines fuelled by hydrogen. In theory, apart from trace hydrocarbon pollution due to lubricants, the tail pipe emissions would be zero in terms of traditionally measured pollutants. The reason for Mazda doing this? The Wankel engine has two major drawbacks – sealing, and a long, thin combustion volume with a vast surface area to volume ratio. Yes, the Wankel engine is ‘emission disabled’.
Meanwhile, BMW built a few factory-owned 7 Series E65 based long wheel base limousines, complete with CFRP body structure inserts around the rear sill/subframe/C pillar area. The V12 engine was fed with hydrogen stored in a large tank located in the boot above the rear subframe (hence the CFRP structural magic parts) and had a small fuel tank located under one rear passenger seat. The vehicle was bristling with contradictions – a huge engine which could run further on the tiny petrol tank that it could from the huge insulated hydrogen fuel tank, which was designed to keep the liquified fuel at -273°C for as long as possible. Oh, and it needed a system to ensure the liquid hydrogen became gas as it entered the pointlessly vast engine.
These experiments confirmed what was already known before any of these prototype vehicles were built. Hydrogen does not have the energy density of petrol or diesel, and there are significant issues in storage of the fuel either at under pressure at normal temperature (i.e. serious pressure vessels) or super cooled at ambient (i.e. seriously bulky insulation).
The second route? Drum roll…the hydrogen fuel cell. This is a form of battery. It has taken many years to develop, and the once sky-high cost of the main component – the ‘stack’ – is gracefully gliding downwards. Essentially pure hydrogen atoms are introduced to oxygen atoms, where a membrane allows the atoms to join and the electricity generated in the process is extracted. This is electric power generation from pure hydrogen and air, using the oxygen in the air. Hydrogen has a greater affinity to oxygen than oxygen has for hydrogen, so only one component needs to be made unstable to create the vital atomic level re-assembly.
Do we need pure hydrogen to do this? Well Chrysler many years ago developed a fuel cell stack that would run on petrol or diesel, but of course the tail pipe emissions, while dramatically reduced, were higher than if we put pure hydrogen into the system. In addition, early membrane technology was highly intolerant of impurities, but much important work has taken place to make the fuel cell stack tougher.
Other considerations
Let’s not forget, if we consider hydrogen fuel cell stack electric power generation to be the future of transport, and bypass the significant issues in creating additional production capacity for pure hydrogen let alone the increase on electricity demand or environmental impact, there is a further important factor to consider. Fuel cell stacks like to generate power under steady state conditions. They do not like Vmax/ standing starts/traffic light GPs.
So, we have electricity generated at a steady rate, but we have demands which are variable and include dumping harvested energy back into the system (regenerative braking). Yes. There’s the clue. In a pure electric system, we have to add a pure electric vehicle in its entirety (low voltage system, high voltage system, power controller, DC-AC converters, on-board recharging, electric traction motor and the energy storage system).
That means we have two powertrains. An on-board electricity generator powered by hydrogen, and a pure electric powertrain. Oh, and while fuel cell stack prices have fallen below €10,000, that’s still way, way more than either plugging a vehicle into a larger, more efficient power generation system (and yes, that’s a story for another time) and even more than an internal combustion engine used as an emergency power generator.
Then there’s business interests. Manufacturers of bottled gas are naturally very supportive of the hydrogen power movement, as are many oil companies. True, initially only Total supported this, but most companies now recognise in the new lobbyist infested world of eco-warriors, selling hydrocarbon fuels needs some ‘eco’ messaging.
The upshot is oil companies (considering profits) and especially government (considering the ludicrous 80%+ tax revenue per litre) do not want to switch off the oil-based economy just yet, and as usual for the public sector, there is no strategy nor plan for any potential transition should the prevailing economic objections to hydrogen (or any other great idea) change. That immediately gets in the way of ‘what comes first’: Fuel supply system or vehicles which can use the ‘new fuel’. The prototype of this situation is rolling out now – electric vehicles have relatively poor access to public charging points, and recharging them in an urban environment can be hazardous for residents. In the UK there are handful of hydrogen refuelling stations, and for the most part the main source of the energy is from bottled gas. Not quite seamless.
While the refuelling station lines and nozzles for hydrogen are bulkier, heavier and bigger than the equivalent petrol, diesel or natural gas LPG systems, there have been zero accidents due to hydrogen leaks during refuelling. Yes, there are tiny numbers of vehicles and some users – such as those operating buses or trucks – could be considered to be even more considerate than the general public could be. There is another major benefit – recharging the energy source takes as long as we are used to, a matter of minutes rather than hours, being kind to the battery, or 30 minutes plus, if we want to sustain long-term damage to the battery.
The future
Is the future hydrogen? Nope. Not for personal transportation, and COVID-19 has just buried the plans for some manufacturers to introduce hydrogen fuel cell powered vehicles.
And yet, there is one need right now. Semi-trailers which are refrigerated are a cornerstone of food transportation as well as medication, and have the ability to be run from the tractor unit, from the national grid or a small, badly made diesel engine. For anyone who can remember being at a Channel Port or EuroStar waiting to board, the sound of these little diesel engines is very clear. It is not always possible to hook up a refrigerated trailer to a fixed electricity source, so a quiet system is required – the fuel cell! This is already underway.
There’s more though. In the unsolved hard-wired world of pure electric vehicles, the process of energy transfer is firmly in the 1800s. If we casually assume this problem will be solved at the same pace as the energy density improvement of batteries, and we venture away from the leafy suburbs of North London, much drama awaits. Further, if one lives ‘in the provinces’ running a pure electric vehicle is not straightforward due to availability of energy top-up points. Enter the hydrogen fuel cell. Suddenly apart from cost of the base electric vehicle, the cost of the additional fuel cell stack system, the energy/environmental impact of making the pure gas… we have a solution.
Rather than drinking the pure water that comes out of the tail pipe, perhaps we really should just drink the finest socialist Champagne. Still, who knows what the future holds?
By Neil Currie
The last two topics in recent issues focused on combustion issues and the various tools, service and repair process available to us. Two reasons have directed me to develop this debate further, firstly an email from my much-respected friend Phil Ellison at ASNU, and a VW Golf edition 30 presented to our workshop with poor running at low and transient throttle position. I was also involved in a conversation with friends in Perth, Australia over valve timing issues.
I’m going to respond to Phil’s interesting input first and clarify something especially important to all diagnostic techs. All decisions we make must be evidence based and not opinion. This is an extremely broad statement, but simplifies the fact that if you do not have access to the required tools, software, or process skillsets your decisions will be opinion-based!
I can relate this to my time building military aircraft, where nothing ever happens as a result of opinion. You could quite literally switch off and simply follow the build schedule and submit your work to inspection. You were not paid to have an opinion. This is why I left!
I may have previously left an impression that it was not necessary to fully evaluate injectors in a test bench, if this was so, then I apologise as my thoughts are the exact opposite. My intention was to ensure that you fully explored all causes of incomplete combustion while the engine is running, as most engine work now carries a high labour content! Do not, however make the mistake of letting cost dictate your process. Phil did pick up on the common issues of injector removal damage where specialist tools are required. The use of fuel additives, which can be a common cause of internal injector damage especially to plastic filter baskets, where any debris is then deposited in the basket effecting fuel flow. Direct injection technology now demands the absolute best fuel quality, often reinforced by manufacturers placing fuelling advice inside the filler flap.
Phil also picked up on a common issue I did omit; Stop/Start. Hot engines with an increase in stop events, with fuel trapped in the injector often causes lacquering of the pintle. Heat in the combustion chamber dries any combustion residue and oil on the injector tip. I’m coming to the inlet valves very shortly…
Fuel trim or correction does not fix problems, it can exacerbate them, imbalance in injector delivery or as Phil pointed out deterioration of the spray pattern will cause bore wash, premature lubrication failure, and an increase in crankcase emissions, larger fuel droplets do not combust fully.
Interestingly, he pointed out that new injectors are produced with a +/- 5% tolerance.
Potentially misleading evidence
The Golf appeared in our workshop just a few days after I had finished my topic. I was not involved in most of the diagnostic process or repair but was in discussion over potentially misleading evidence.
The vehicle had covered 106,000 miles, and was suffering from poor idle and incomplete combustion, with a mil light indication.
Step 1/ serial interrogation
0568/P0238 boost sensor, signal high, frequency 1
0768/p0300 random/ multiple cyl misfire, frequency2, counter re-set 255
0772/p0304 cyl #4 misfire intermittent frequency2 counter re-set 255
The next step taken was a cranking current differential test, showing no apparent mechanical imbalance? Back to this later.
Coil and plug failure is a common problem and is an obvious job for the Pico scope, no problems with burn times or primary current saturation here.
David Gore, our diagnostic tech, opted for the first look sensor in the exhaust next. I’m not sure if he opted for WPS in cylinder or not. This would have been my preferred choice, but as the saying goes too many chefs…
If you refer to Fig.1, The image is triggered from ignition, sequentially 1342 from left to right. I’m going to let you debate this image, as I intend to cover this in detail next month. I bow to Brendon Stickler’s wisdom on exhaust pressure evaluation. My debate is focused on the properties of pneumatic pulse delay from the cylinder head to tail pipe. I have since proven this and will discuss this in the October issue.
The next and obvious decision was to remove the manifold and check the intake tract and valves for carbon.
So, as you can see in Fig.2, there is excessive intake valve carbon. This is due to several factors, the most common of which is no self-cleaning from the fresh fuel air intake cycle. Other factors include, lengthy oil service intervals, not replacing oil separation filters, poor fuel quality, driving environment, poor or incomplete combustion cycles, incorrect atomisation and air swirl during the intake and combustion preparation cycles. Remember, direct injection can separate the fuelling into several events on both the intake and compression strokes.
Value
Back to a comment I left open earlier, I hope you are still interested? The value of compression is determined by the mechanical engine efficiency and volumetric efficiency, Pumping losses! So why didn’t a problem show up during the cranking balance check? As this test is based on compressional resistance. Accepting that when the engine was at idle it ran badly and would eventually disengage the injector cycle in cly #4? the answer is rotation speed increase reduces the available time to draw in fresh air. If you compare nominal compression values say 10-12bar against the value at idle they will only be around 3.5 bar!
The detrimental effects of intake fouling only tends to occur at closed and partially open throttle, where the pumping losses are the greatest. The dtc relating to boost pressure sensor value high, can be caused by ignition misfire or unstable intake pulses.
Finally, the injectors were subject to the Spanish Inquisition in the ASNU bench. The results (see Fig.3) confirm substantial fuelling imbalance causally relating to my previous comments.
My grateful thanks to Phil, David (and myself), for the technical input in this topic. I’m off to the workshop to check the delay characteristics with WPS in cylinder and FIRST LOOK sensor in the exhaust.
Frank continues his look at combustion complications and throws the net wider to include the impact of peripheral systems
Do you ever get that feeling? You know the one. You turn the key in the ignition, the car cranks, cranks some more, and then some more. You’re willing it to start, but all you're met with is an ever-decreasing RPM as the battery dies along with your hopes for what was going to be a pleasant day.
Groundhog Day
The sense of doom can often be exacerbated by the fact that a bunch of new bits have been bolted on and the car has been with you all week. I think we have all been there at some point. My key message here though is that it need not feel like this, there is a way to avoid Groundhog Day.
My formative years in this trade were spent working in the family business and it’s the banter between my younger self and my father that reminds me of the path away from Groundhog Day. It went a little like this: “You’ve got a lot to learn son, this game is all about experience” was a familiar message. My dad was right, I did indeed have a lot to learn and you really can’t beat experience. But regardless of how true the message, the regularity at which it and the humorous variants we’re delivered began to grate a little. I needed a witty retort, and then I found one: “You don’t have 30 years of experience dad. You have one year of experience that you’ve repeated 30 times.”
It cut like a knife and although it wasn’t true about him, I can’t help but feel that it’s just so easy to get stuck in a rut and not look for alternative ways to expand our knowledge and make diagnosis just that little bit more enjoyable.
Is that a glimmer of hope I see? Of course it is and all it takes is your will to change and break the cycle. How can the feeling of doom be reduced? Quite simply by improving your process, using the right information and carrying out more tests than are needed on your path to diagnostic stardom.
And the good news is that this is the first article in a series of technical hints, tips and tricks all designed to help you break the cycle. So where shall we start.
I’d normally kick off by looking at your diagnostic process. That being said I’ve covered it in detail previously so I’ll skip it for this article and jump straight into something technical. But just before I do here’s something to remember.
It’s very easy to become consumed by shiny diagnostics. I love cool diag as much as the next geek, but I’ve noticed Pareto’s Law (the 80/20 rule) at work all too often to be tricked into going down that road. Which is why this series will focus on the 20% of the diag that fixes 80% of your problems. let’s get started.
There are many routes you could go down and for this vehicle we’ll assume you’ve no fault codes, your serial data looks good and cranking speed for this petrol car at 250 rpm is on the money. Ultimately you don’t have a lot to go on, so what next?
At this point it’s all about finding diagnostic direction as quickly as possible, you need to find a clue, something that’s out of kilter. And that starts with a 3-step routine that should be second nature for non-start diagnosis and all being well will give you direction.
The question is, do you have a mechanical issue, a fueling problem or an ignition fault?
There’s only one way to tell and that’s to start testing. We could discuss the order we attack this in at length but I’ll normally start with mechanical, then ignition and lastly, fueling. My reasoning being that fueling issues can take a few minutes longer than the other two to test. If I find an issue on my first two tests then I have the initial direction I’m looking for and I’ve shaved a few minutes as well. What fundamental tests should you carry out as part of your non-start routine? That’s straightforward, just grab your scope.
My favourite test at this point is a relative compression test. It’s quick to complete and reveals so much information in such a short amount of time. To set the test up, simply attach your high current clamp around your battery negative cable/s, select a suitable current and timescale, crank the vehicle and you’re off to the races.
Fig.1 shows a good example. Point A being the current to commence rotation and the peak on the subsequent humps is the amount of current to drive a cylinder through its compression stroke. You’ll no doubt have concluded that if you have a single low peak then compression is low on a cylinder. Should your scope support the function, it may be possible to display this test as a bar chart. It can be easier to identify an issue here rather than analysing the current waveform itself.
There’s one key point to remember though. This is a relative test and it may be possible to have more than one cylinder that’s defective and pass the test. I’ll cover this in an article of its own in this series though.
If the relative test shows an issue then you’ll need to carry out a physical compression test for conformation, followed by a cylinder leakage test to discover why. Haven’t found an issue? Then it’s on to your ignition system next.
Ignition Testing
The name of the game is a quick test rather than in depth analysis at this point. The question being: Do you have enough energy to produce a spark for good ignition?
In Fig.2 You’ll see a secondary ignition waveform. Looking at the firing KV at Point B, for sufficient energy to initiate a spark, comparing this on all cylinders and looking for anomalies is a great place to start. Should I have one that’s too low or non-existent, then I’ll be checking powers, grounds, and primary switching at the coil, before considering the possibility of a defective coil. All good? If that’s a resounding yes then let’s take a look at fueling.
‘Those in the know measure flow’ are wise words, and I’ve used flow testing to find many fueling faults. In this instance though, we’re looking for a test that gets us in the ballpark to assess if fuel is being injected. You have a few options. You could:
Opt for a visual inspection of the plugs. Are they wet?
Use a gas analyser pre/post cat.
Do you have HC?
Scope injectors and fuel rail pressure – Does the rail pressure drop while injectors actuated?
No HC, dry plugs, lack of injector actuation and questionable fuel pressure, all give you diagnostic direction and highlight additional testing is required on your fuel sub system.
Found your way?
All being well, your diagnosis now has direction and a path to more specific faults in a given sub-system. Assuming reasonable accessibility and a little practice you’ll often be able to complete those tests in around 30 minutes(ish), which will leave you with at least another 30 minutes to further explore any issues before presenting your findings to your workshop manager.
One thing’s for sure; Having a structured approach to your fault finding, looking for diagnostic direction, with a few familiar tests up your sleeve will reduce your diagnostic time and increase your confidence exponentially. Want to know more? If so then take a look at next issue's article where I’ll be taking a look at some actual non-start issues with detailed test results.
If you’d like to learn how to improve your diagnosis skills then call John on 01604 328500. Auto iQ have a complete technician development programme designed to help your technicians be the best they can be. To join AutoiQ’s online forum go to: autoiq.co.uk/garageowners
Combustion problems have been with us since the dawn of the internal combustion engine, and they continue to occur as technology changes
Fig. 2
By Neil Currie
After my recent articles on tyres and TPMS systems, this month’s topic is wheel alignment, and the massive impact excessive toe-in or toe-out could have come MOT time.
A lot of us can spot alignment issues a mile off. I would worry if after 17 years in the trade, that a technician such as myself couldn’t tell the difference between a tyre that had been toeing-in and a tyre that had been toeing-out most of its life. If you look at a front tyre on a car and only the outer edge is bald (and the tyre has plenty of pressure in) then you walk around to the other side and discover the same issue with that tyre, it would be plain enough to see that the wheel geometry isn’t correct.
Compensate
A car with tyres like this and wheel alignment so far out must handle like it has a mind of its own - like Herbie the Beetle. However, people get used to a car in this state and will compensate to a surprising extent. When we take the car for a test drive, we may come back to the customer and say things like; “there maybe an issue with the tracking” or “the car is pulling rather a lot to one side.”
The customer then looks at us in amazement as if we are saying things just get their hard-earned money from them. We then offer a FREE wheel alignment check, and show them the virtual view on the screen. By Jove, the customer can then see with their own eyes exactly why their tyres have worn the way they have.
I first mentioned toe in and toe out. This is the way the wheels ‘point’ in relation to the forward motion of the car. Look down at your feet. Now keep your heels in position, and point your toes inwards so they point towards each other. If you try walking like this you will wear off the outside of your shoes first.
Do the same again with your heels, but point your toes outwards. This is toe-out and walking with excessive toe-out will wear the inner part of your nice new shoes and that’s the last thing you want. I’m sure you’d like it if your shoes wear evenly. The majority of track cars/race cars will be running with toe-out and negative camber. This will be topic of conversation next time as wheel geometry is a large subject.
Minutes and degrees
I also mentioned minutes and degrees earlier too. A while ago I tried explaining this to another tech and he struggled to grasp the concept of the theory behind alignment/ geometry, but he knew how to set the wheel alignment up on 99% of cars.
Getting your head around the actual maths is a different story. Think of it as a clock; there are 60 seconds in one minute; there are 60 minutes in one degree; and there are 360 degrees in a full turn. Our alignment set-up only works in minutes and degrees as it is really sensitive so no need for seconds-it would be worthless. The wind could blow and move the car slightly and that’s enough to make you panic and pick up your spanners again.
Once the alignment is set-up correctly and you’re happy with the end result, your customer will in turn be very happy. Remember, in the end they are the ones paying our wages, not just your boss. It does help if you have a happy boss too of course.
I find it difficult to comprehend the events of the last month since returning from Australia. The temptation to write exclusively about Covid-19 and the effects on our industry was hard to resist. I have therefor directed my focus on positive issues, and continue to tell you what I learned during my trip.
The stopover in Hobart, Tasmania was brief. Before docking in Melbourne, I was able to climb Mount Wellington, which is over 1,000 metres tall. The temperature was near zero and visibility the length of your arm. It reminded me of Snowdon summit. The Captain then announced that the remaining cruise, scheduled to conclude in Singapore would be suspended and would prematurely end at Perth due to the Coronavirus outbreak. Majestic Princess is the sister ship to the one in lockdown at Yokahama, Japan. The third cruise liner was later in quarantined in San Francisco bay.
Two internal flights took me to Dubbo for the next to-day training session, the Australian Aftermarket Service Dealer Network (AASDN) group once again providing delegates from north-east Australia. I have the greatest respect for this network. Its membership includes the very best independent technicians all working together in a mutually respectful environment, something we in the UK need to reflect upon. They travel thousands of miles to attend training seminars, sharing an inter-group communication network to be proud of.
Genuine passion
Remarkably, they do not have access to manufacturer tools and repair data, and are currently fighting the federal government for the Right to Repair Bill. Does any of this sound familiar? Therefore, as it stands collaboration with dealerships for programming and component replacement is absolutely essential.
During my week-long stay, I had the opportunity to spend a day training a young technician at Pat Crowley Automotive. It is refreshing to meet young apprentices with a genuine passion for their career development. The final week of my tour bounced me back all the way to Perth.
I was introduced to entirely new AASDN group members as well as Capricorn. You may recall my comments regarding membership group benefits. Capricorn is the company based in Perth that provides the corporate veneer to group membership; everything from operation financing, legal services, health and welfare and managerial software. They also provide parts finance factoring, as opposed to parts supply. The individual members order parts from a variety of suppliers then settle a single invoice from Capricorn at the month end.
Their services also extend to unique access to corporate insurance, banking, legal services including, employment contract, leasing agreements and property law.
Insights
So, what have I gained from my second visit down under? Number one has to be a renewed friendship, one I value very much, an insight into how individual small businesses can co-exist in harmony within a competitive environment, and one which lacks a great deal of what we take for granted in the UK.
Despite having no emissions regulations whatsoever, the workshops I visited have an advanced understanding not only into the operational functions of Euro 5 and Euro 6 but in my opinion, a more advanced approach to service and repair options. Yes, I do mean that. There is no requirement for any vehicle to be subject to an emissions test. Amazing isn’t it?
Despite this, and the fact that there are almost no Euro 6 vehicles in Australia, the diesel emission course was one of the most popular. Companies like Rincap Automotive not only import specialist ultrasonic baths from Spain but also high-quality OE DPFs from Wales. Not New South Wales, but the one separated by Offa’s Dyke.
Cat and Pipes provide OE replacement DPFs across the globe. Rincap owner Bryce also has fully grasped the initiative of recovering DPFs and EGR coolers in factory-controlled conditions. (See Fig.1 and Fig.2). That statement is intended to focus on current popular on car treatments in the UK which simply contribute pollution into the atmosphere or drainage systems .
Dig down
In Sydney, where land is more expensive than a divorce settlement, they build up or dig down, creating multi-storey workshops. To give an example, the main Audi dealership in Sydney is housed in a high street multi-storey complex.
So, this brings me to a confidence I have been carrying for some time, the Pico 4425A! This is a development from the current range of scopes but now including active probe inputs (See Fig.3 and Fig.4)
What are the advantages? Simply connect the input device to a channel and it will auto recognise it and select the appropriate scaling. You can conduct a circuit load test with the appropriate resistive lead supplied. The new version offers much better sensitivity at both higher and lower frequency ranges. The probes contain a small active amplifier close to the probe tip, thereby reducing the capacitance of the probe, often less than 2pf. This offers a much higher bandwidth.
We will be introducing a scope update training programme as soon as 4425A and Pico 7 become fully available. Please note the non-standard cases that can be provided for WH kits supplied by ADS.
My personal very best wishes, and best wishes from all at ADS. Keep well and look forward to the UK recovery with confidence.
Fig 2.
If you're a ‘go get ‘em’ garage owner, then you’ll have been keeping a close on the new technology hitting our roads. You would have been forecasting what this means for your business, and starting to build a strategy comprising the changes you’ll need to make in the coming months to ensure your team are prepared and your income guaranteed.
While the number of EVs on our roads is increasing the market has been missing that special something. Well, perhaps not any more. This month, the long anticipated EV Mini has been released. It’s got that certain je ne sais quoi you’d expect from a Mini, and the starting price of £24,400 has ensured buoyant sales. The interesting thing being that this is just the first of A LOT of popular EVs that are being released this year and there’s no doubt that this will raise the awareness of your non EV customers and move the market closer to a tipping point. You just need to make like a boy scout.
Be prepared
Depending on your time in the industry, you’ll no doubt have experienced such technological revelations as the death of points and the introduction of transistorised ignition, computers to control fueling and catalysts to save the planet, not to mention more sensors and actuators than you could shake a stick at, and fault codes to tell us what to change (NOT).
We’ve taken injectors out of the inlet manifold and shoved them directly in the cylinder (GDi,) and then created cars that have both manifold injection and direct injection combined. We’ve downsized engines, added a myriad multi turbo options, and more emission saving devices than you’d have ever imagined conceivable! It’s almost enough to make your head spin! There is good news though.
Every time a new technological change emerges it gives you the opportunity to move with the times and get ahead of your competition. Today, you’ve got that opportunity in spades. It’s just a case of dipping your toe into the world of EV, becoming familiar with the technology and embracing the opportunities.
Same tech different model
As always, a little research often relieves any technical anxiety that may exist around new systems and EVs are no different. You’ll find the same type of components on a Toyota Prius as you will a BMW i3. They all have high voltage; batteries, relays, inverters, DC-DC converters and motors. It’s not quite you’ve seen one and you’ve seen them all, but when you compare one manufacturer with the next it’s plain to see the commonality between the operational characteristics of the systems and components, which is comforting for those delving into this technology.
Back to diagnostics
We took a quick look at HV batteries last month and I figured it’d be a good idea to take a look at how the high voltage made its way from the battery to the Power Electronics unit (inverter and DC-DC converter). Enter the high voltage relay pack.
High voltage relays exist to separate the HV battery from the rest of the HV components. They’ll be open circuit with the ignition key removed, and closed with the vehicle's ready light illuminated.
Fig.1 shows an example of a high voltage relay pack, Fig. 2 a wiring diagram and Fig. 3 the relay control circuits and high voltage current when scoped.
While the relays are spec’d for high voltage and high current they have three independent 12v control circuits. The eagle eyed among you will also have noticed that while we have two HV cables (one +, and one -) that there are three relays utilised within the system. Let’s take a look why.
Three into two goes
If you look carefully at Fig.3, you’ll see that while we have three relays, relays one and two are connected in parallel. Look closer still and you’ll also find a resistor ( r ) in the current path on relay two. So why three relays? It’s all about control.
Take a look at the scope and you’ll see that relay three is engaged followed by relay two. Relay two having a resistor in series with it, ensures that current flow to the power electronics is reduced. Why? Good question.
Were this not the case then it would be possible for a very high current to flow as the contacts closed, and the possibility of an arc forming between the contacts. This is obviously undesirable and could lead to a reduced service life for the relays.
Relay three is closed followed by relay two, current between the HV battery and power electronics raises to just over 10 amps initially, and reduces as the voltage at the power electronics becomes closer to that of the battery. As the PD between the battery and the power electronics is the same-ish. Relay one can be closed without arcing. Relay two is no longer required and can be disengaged. Hey presto your Ready light will now be burning brightly and the vehicle ready to drive.
Just in case some of you are asking “Why does the relay control circuit voltage rise from 12v to 14v at point A?” Well, as the ready light is on the DC - DC converter has come online to charge the 12v battery and power the consumers on the vehicle. It’s all very cool and I’d go into more detail but we’re out of time for this month, so you’ll have to keep your eyes on our future articles for that one.
Where next?
Once you dip your toe in the water you’ll see that the fundamentals of EV technology are straightforward, and where appropriate training, tooling and information are employed can be painlessly integrated into your workshop.
You’ll benefit from an increased confidence throughout your team, and additional revenue from work previously sent elsewhere. What’s not to like about that? Not much!
Need some help with your EV training and qualifications? As always I’m here to answer your questions. If you’d like to find out how Auto iQ can help your garage with our training and consultation programs then feel free to call on 01604 328 500.
If my topics are measured by the readers on variety and technical content, then this month’s offering should not disappoint. As I am writing, I am gazing out from my hotel lobby in central Sydney, yes, the one with the bridge and opera house. This is my second annual tour delivering a series of technical diagnostic subjects to the members of the Australian Aftermarket Service Dealer Network (AASDN). The ASSDN was formed by former members of the Bosch Australian Aftermarket Dealer Network (BASDN), which had dissolved.
ASSDN Membership provides a range of benefits including training, preferential insurance rates, as well as group buying incentives with monthly settlement. This tour, taking place over 32 days started with my arrival in Sydney via Etihad from Manchester. My first adventure consisted of three days VIP entry at the Bathurst 12-hour world series. Bentley came first with McLaren second. The Germans came in later.
I was then in the hands of my friends at Queanbean Diesel Services. Ros and Derek became friends last year as one of my training venues. Not ignoring the fact that the city was surrounded by wildfires, I enjoyed two days with some hands-on workshop time.
Workshop tasks
Task 1: 4 cyl diesel, no combustion no4, presented with, an exchange engine, and new injectors fitted. A quick current ramp check on all the injector circuits confirmed no current on no4 cyl. Continuity from PCM to injector good, no path to ground, and no short across both circuits. Looks like PCM, but there is no time to consolidate the results.
Task 2: VW Passat 2.0 edc17; Lots of money spent elsewhere, flat performance until 2,000 RPMs then off like a wombat going for lunch. A short test drive with VCDs confirmed that request and actual turbo boost are out of sync. No obvious boost leaks, vane actuator motion looks ok. Diaphragm good. Recommended detachment of actuator rod in order to check free movement of the vane control ring. Suspect turbo a problem. This has just been confirmed.
Task 3: Common rail diesel commercial vehicle, intermittent no start. Test conducted at the rail pressure sensor. It showed no voltage increase when cranking, suggested check priming system, however the hand lift pump did suggest fuel was present. Advised check Drv actuation value for 18%-25%, then look for internal leaks and possible debris contamination in rail. This was also confirmed a week later, the vehicle had previously been cleared of debris in the tank, further debris was present in the Drv. Now running ok with new actuator. I very much suspect it’s not all been irradiated.
Events
That was a good warm up for my trip back to Sydney and the first event at BWA. Bob Whyms is Mr Porsche in Australia. He comes from my generation, Bosch D Jetronic, KE, K, and all that early fab stuff. He has a superbly equipped shop, full of all sorts; Dyno services, machine shop, Carbon Zapp, diesel and gasoline test bench facilities and much more. The event hosted over 30 of Australia’s leading diagnostic techs and shop owners. Subjects included ignition systems, as well as commonrail diesel and direct gasoline injection. The guys really responded to the Euro 6 emission presentation, and were fascinated by test opportunities using NVH and WPS, especially when demonstrating combustion imbalance using NVH. Torrential rain over four days complimented the event as it did last year. I am now officially ‘The Rainmaker’, move over Matt Damon!
Visits
Two final days in Sydney were spent with Mike and Bryce, two shop owners with incredibly different approaches I also had the great pleasure of a private luxury cruise around Sydney harbour, beer and canapés courtesy of Mike, owner of a local garage called 313 Automotive. His business sports a fantastic split-level immaculate workshop. There are cars and lifts at ground level with full engineering services below ground. I didn’t think I would ever meet anyone with my level of passion for a clean shop. I was delighted to be proved wrong!
The second visit, at Rincap Automotive, was of very special interest to me as my opinions on DPF service and recovery have become focused around the need for a precise factory-controlled process. Bryce and his namesake father Frank have been DPF recovery pioneers in Australia with the application of ultrasonic recovery for blocked DPF, charge coolers, and intake systems.
They have just moved into a magnificent new-build shop with the upper floor dedicated to various state of the art ultrasonic processes, with a fully equipped training room providing techs with the systems and skills training essential for durable DPF recovery.
With a two-day free period, I just couldn’t miss a walkabout in Sydney. I also needed a few bits and bobs for the next training venue. We were struggling to connect Sydney with Melbourne, so it was agreed that, although not ideal, we would hold the next AASDN event on a cruise liner four days outbound for Melbourne via Hobart Tasmania. I have struggled over a few venues in my career, so the first-class dining room was something different. I didn’t make a meal of the presentation with subjects from NVH to WPS, Euro 6 proving more than a mouthful.
While the lockdown is the reality for now, once restrictions ease, it will be time for mechanics and motorists to accelerate say Kalimex
We have arrived at the fourth final part on the subject of tyres. This month, the focus is on the MOT, regarding tyres and tread depths. I’m hoping the manual hasn’t changed by the time this is published, (the MOT manual is, after all, changing all the time). As I write this, it states that the legal limit for a passenger car with no more than eight seats excluding the drivers seat used on or after 3 January 1933 is 1.6mm around the whole circumference of the tyre across the central three-quarters of the tread area.
Therefore, if a car was to come to me for a MOT with one or more of its tyres measuring 1.6mm, I would be forced to pass the car with just advisories on the tyres in question. This is a shame as you wouldn’t want to send a car out of your depot with a tyre on the legal limit and 100% worn, would you? The owner could quite easily travel 100 miles or so in the next few hours and their tyres may very well be then deemed illegal If stopped by the police.
“But officer! My car passed its MOT earlier today" may well be their perfidious reply. I suppose all that matters is how the car was presented at the time of test. From a tester’s point of view though, you cannot try and pre-empt what may or may not happen after the test. The car maybe stored in a garage for months at a time for all we know. It may only do 200 miles a year. Regardless of what we think may happen, by following the guidelines and rules set out in the manual you can’t go wrong. As long as the customer in question is made fully aware of the situation and you’ve made the best judgement call you can, then you have done your part and can you sleep at night.
Measurements
Here are some measurements to get your head around regarding tread wear: 8mm-0% worn; 7mm-16% worn; 6mm-31% worn; 5mm-47% worn; 4mm-63% worn; 3mm- 78% worn; 2mm-94% worn. Obviously 1.6mm would be 100% worn. However, as I mentioned, it still passes an MOT as an advisory. A tyre on 2mm also passes but certainly with advisory notice. Me, I give an advisory notice for a 3mm tyre. To me when something is 78% worn, it’s almost had it. If you were to wear a pair of shoes that were 78% worn, I would think that somewhere along the line someone may advise you to replace them too, as they’d look pretty shabby.
The garage I work in receives tyre bookings all the time from cars that have been for an MOT elsewhere, a lot of the time, at a main dealer. For some reason they have advised tyres on 4-5mm tread readings. I’m not sure why, as a 4mm tyre still has some life left in it, and a 5mm tyre certainly shouldn’t be classed as worn. Maybe the testers are overzealous. They should take their tread depth gauge and make sure its calibrated. There was me thinking I was being cautious advising on 3mm! I like to think I’m firm but fair when it comes to testing. I’d like to think others are too. Lastly, don’t forget, the next time you’re out walking in bad conditions and keep falling over, check the tread depth on your shoes, it maybe time to replace them.
Issues with tyre pressure monitoring systems will become much more prominent and regular in the majority of workshops all over the UK. Since 2014, every car sold new in the European Union was required has to have a form of TPMS. There is no way of escaping it. As a technician you can try and hide from it if you like, but it will find you and it will make your brain engage when that little warning light ‘pings' on the dashboard.
The thing that a lot of techs don't know is that the first form of TPMS was first put into practice in the late 1980s, so it is not as if it’s a new idea. Back then, it was mainly for high-end luxury cars. Now a very high percentage of low-priced to mid-range priced vehicles are fitted with a TPMS system. You can even buy a retro-fit system and put it onto your motorcycle if you wanted to!
Types
There are two different types of monitoring systems. The first is a direct system in which the sensors are held within the wheels. These send a radio signal to the car and this is converted into a real-time display on the dashboard for the driver to keep a close eye on all of the pressures individually. The second is the indirect system. This one cannot show you a real-time value as there aren’t any TPMS sensors to send a radio signal back to the car. Instead this works via the cars wheel speed sensors/ABS sensors, to put it simply- it counts the rotations of each wheel and recognizes a fault if one wheel turns quicker than the other three. Clever or what? Well, not really, if all four tyres lose pressure.
Prod and cons
When it comes to TPMS pros and cons, my personal thoughts are that these systems, particularly the direct system will make for safer roads and therefore save lives. Not only that, the fact is that it is going to save your tyres, and by keeping the optimum pressure in them, saving your tyres will save you money, and if you save your money you will then be able to afford to buy new sensors if (when) they break... and they do break, whether it’s the core (due to bad practice when fitting tyres and not replacing something as simple as the core and the valve cap) ,a leak from the base of the stem or simply the battery going flat inside a sensor... (majority not interchangeable).
The simple fact is they do go wrong sometimes. Besides the main disadvantage of the indirect system that I mentioned earlier, if they do go wrong and it is obvious that the TPMS system isn’t working correctly, come MOT time the car will get a major fail. However, if the car is registered before January 2012, this doesn’t matter, which probably wasn’t the best decision ever made. I think any car equipped with a TPMS system from the factory should have it working. Simple as that, but that’s just my opinion.
Optimum
If one or more pressures are low and the tyres look ‘obviously Under Inflated’ then that induces a pass with a minor defect. The facts is that thousands of accidents and hundreds of deaths occur every year due to under inflated tyres resulting in tread separation and ultimately failure of the tyre.
In short, tell your customers if they want better fuel efficiency, better handling and optimum braking, they might want to check their pressures, even when the MOT is not looming.
VARTA provides advice to workshops for the business re-start, and how batteries are a good starting point
I’m mindful of several recent diagnostic topics that focused on cutting edge opportunities such as noise and vibration analysis. It also reminded me of the most important aspects of fault finding; to focus on the symptoms, ask relevant questions and conduct a methodical approach based on systems knowledge, accurate data and a proven process.
All of this really boils down to training, experience, and confidence. There are no short cuts, cheap fixes or internet gurus. There are however basic steps that are easily introduced into your workshop procedures.
This brings me to the topic in hand. Can we conduct relativity simple tests on common rail diesel systems? Not only can we, but we must! Remember, the foundation rule of fault finding is a simple methodical approach. Don’t expect a magical fix-all in less than 1,000 words. However, I can provide a pathway that will illustrate the area of responsibility and potential investment in time and money.
Vital information
The first vital step is to listen and ask questions. Owners often have vital information. Remember this is not a recipe for short cuts or silver bullets for your machine gun. Your approach will always depend on the extent of problems. Will it run? are there any mechanical noises? Is there a loss of power? if so when? Is the fault intermittent and how did it start? There is an endless list of questions that will help establish a hidden history.
I often find that a physical examination or health check helps understand the way the vehicle has been driven and serviced. This will often expose basic problems especially with charge pressure circuits.
Try to explore all non-intrusive tests first. They may not be entirely logical in order of priority, but do provide results in the minimum time period. With experience, you will hone these steps into a razor-sharp intuitive process.
Serial investigation
Serial investigation is without doubt the correct first step. Do not jump to premature conclusions as serial data often shows symptoms, not cause. For example, a faulty air mass meter will cause EGR calculation error values, incorrect load and boost calculation. This is a common problem with many causes.
The volumetric efficiency relies on the intake system, swirl flap control, turbo spooling, and a free-flowing exhaust system. Please note that I keep my thoughts non-specific yet focused on all possible causes. This is a very important reaction in any diagnostic process.
Assuming a non-run condition, excluding any serial clues as often there are none, I would always check for the correct rail pressure. This can be done with a DMM. Expect around 1-1.5v with a quick rise time of 0.5-1sec. If it is slow to rise or low, check the priming system including the filter. This should be done with a gauge. Remember pressure, flow and pump current. This will depend on system type so check the schematics carefully. Most systems now prime at 5-6bar.
Isolate components
A slow rise time may be due to an internal leak or worn components within the high-pressure system. This includes the HP pump, rail limit valves, and injectors, as well as volume and pressure regulation devices. Always isolate various components and conduct a blind or proof test before suspecting the pump. They rarely fail, unless run dry or have contaminated fuel.
The PCM requires camshaft position data to sync the injectors and crank position once running. If recent belt replacement or engine repairs have been carried out, add this to your list. To check the injector sync against cam and crank position is a bit technical. To perform you will require a scope and current clamp.
Quite often the serial data identifies the incorrect timing sensor for position error. This is due to the PCM looking at the camshaft first. Slow rotation speed may be due to a faulty or incorrect battery, so check charge and health status with a suitable conductance tester. Yuasa have a fantastic free online training academy.
Next check relative compression. This is a simple cylinder balance check but when compared with current and rotation calculation will accurately predict correct compression.
Identify
A blocked exhaust or failed open EGR will prevent the correct combustion properties. Exhaust back pressure can easily be proven from the map and DPF pressure sensors. Plotting them with a scope will quickly identify intake or exhaust restrictions. The maximum DPF sensor value cranking or at idle should be 0.5-1.25 volts, 100mbar-1.5psi.
Injector type, solenoid or piezo faults will normally be identified within serial data. A single faulty injector circuit will normally shut down all fuel delivery. It is also worth noting that if a minimum rail pressure is not reached, the injectors will not be activated.
So back to priming. Leaks, faulty rail sensors will all contribute to a non-start.
If you are looking for more information, visit www.ads-global.co.uk for courses and dates, and Autoinform events.
The Parts Alliance is encouraging garages to proactively offer a battery testing service to their customers and have produced a range of marketing materials to help.
JLM Lubricants has developed a GDI Injector Cleaner that’s been tested by Millbrook Proving Ground in Bedfordshire
Snap-on has added a tool matcher feature on its website. Technicians just have to complete a short survey about the jobs they perform every day and the features that they use or believe would come in handy.
With vehicles subjected to prolonged periods of inactivity, the message from ECOBAT during the lockdown, is to indulge in a bit of charge mania.
Laura Jones, Marketing Manager for ECOBAT Battery Technologies (ECOBAT), observed: “The unusual conditions in which the country currently finds itself are not just a challenge to individuals, but also to the vehicles that, under normal circumstances, motorists would be using daily.
“Perversely, because they incorporate systems and components, such as air conditioning/climate control for example, that can be negatively affected if the vehicle isn’t driven regularly, being left undriven is a far bigger problem for cars than if they are being used constantly.
“At the top of the list though, is the battery, which left completely untouched, will naturally discharge and eventually have insufficient power reserves to start the engine. The problems do not end here however, as the battery is responsible for maintaining a host of electrical components and systems, so being unable to start the engine is just one of the potential issues of an unused vehicle.
So what’s the best approach? “An intelligent or smart charger, such as one from the Numax ‘connect + forget’ range,” explained Laura.
“Despite being thought of as a relatively simple product, there is a lot more to a battery than many people appreciate, not least its voltage and what defines ‘flat’. It might well surprise many that registering less than 12.35-volts means it is seriously discharged and should be charged immediately.
“These facts don’t just have implications for motorists however, they also need to be taken onboard by the trade, because as well as the opportunity for factors, retailers and even workshops to provide motorists with useful battery care advice, they can also offer the Numax ‘connect + forget’ chargers drivers need to maintain the health of their car battery during any period of inactivity.
“The charger does this by automatically checking the battery’s state of charge and adjusting its charging pattern accordingly, so that once it is charged, it will monitor its condition and if necessary, exercise the battery and regulate the power input, to maintain the ongoing performance of the battery.
“However, those supplying batteries also have a responsibility for their existing stock because although the batteries ECOBAT delivers to its customers will be sufficiently charged, if they are left on the shelves or on the shop floor for a prolonged period due to the current reduced demand, for example, they could drop below the 12.35-volt level and will therefore be unfit to be supplied to workshop or retail customers without being appropriately charged.
“Moreover, a battery discharged in this way will not be accepted as a warranty claim as there is no underlying fault with its quality or manufacture, rather the problem is with its upkeep, which is the responsibility of the outlet supplying it to the end user, whether professional installer or the general public.
“Therefore, in order to correctly charge a discharged battery, or to manage a battery that is connected continuously, to ensure it remains in its optimum condition, a Numax ‘connect + forget’ charger is also a great option for those in the trade, as it allows them to supply customers with confidence, which is particularly important in these current challenging times.”
www.ecobat.tech
Picture this… It’s 2011, and I’m a much younger (and slimmer) version of myself. I’m delivering a training event in Chester so that the eager and excited delegates can learn about hybrid electric vehicles, pass their IMI HV qualifications and put their new-found skills into practice.
We were doing the usual rounds of quick introductions enquiring as to why each delegate had attended, and their desired outcomes from the training sessions. Many of the delegates, being technicians, had been sent by the business owner to ensure their team were safe when working around this technology, but one garage owner was there with a sole purpose. He wanted to get the jump on his competition and own the market for HV servicing and repairs in his area.
As you can imagine there were more than a few raised eyebrows in the room, mostly due to the fact that in 2011 only Toyota and Honda were producing these vehicles in any number, and the overall car parc was low. Nonetheless, one delegate had a vision. Everyone else thought we had some way to travel, and do you know what? As much as I loved the technology I could see their point of view. But, if the same statement were to be made today. Well, what do you think
So... are we there yet?!
Quite simply…Yes, and we’ve been there for some time. There’s a significant increase in awareness among the population, electric vehicle sales have seen a sharp increase, and this is only due to gain momentum with so many new vehicles this year being released by major manufacturers. Add to this the reduction of BIK tax to 0% and the positive effect this will have on electric company car sales means it doesn’t take a genius to work out that you’ll be seeing more of these in your workshops.
“I know it’s coming but…” Is not an uncommon retort to my enthusiastic musings on all things HV. I get it, but consider this. I’ve seen enough new technology introduced to our industry over the last thirty years to know the garages that grasp the nettle, understand the new elements of diagnosis and repair, and market their new-found skills, often have a healthy income stream for around a decade prior to their competition catching up. The BIG question is... Will you be going for first-to market-advantage, or playing catch up?
The good news is that while the technology may be a little different, the same rules of engagement apply. If you’ve been using our 15-step diagnostic process, and have proficient electrical knowledge then you’ll be well set to do battle with EVs and come out the other side triumphant. It is with this in mind that I thought you might like to take a look at some fundamental technology and HV diagnosis over my next couple of articles.
Let's get started – High voltage batteries
We’ll be taking a look at a Prius. The source of power is a NiMH battery that resides beneath the luggage compartment in the boot of the vehicle. The battery consists of 28 7.2 volt packs, each comprising 6 1.2v cells. The 28 packs are connected in series to give a total of 201.6v for the entire battery (fig.1).
The battery is air cooled by a multi-speed pulse width modulated fan drawing air from the cabin across the battery. The batteries temperature is subject to monitoring by three temperature sensors set equidistant (ish) across the batteries length. All pretty straightforward stuff, but do they go wrong? Well, from time to time – yes.
Where does diagnosis start
Like I said, “usual rules apply” and diagnosis starts with fault codes. A common battery code is P0A80-123. It is often accompanied by the HV fault light and the internal combustion engine running more than normal. As always, with fault codes in hand it’s off to take a look at serial data. Techstream – Toyota’s Tool – is readily available and not expensive, although you’ll also find many aftermarket tools offer the data required. But without knowing what good looks like, how can you tell what’s hot and what’s not?
Desk Diagnostics
At this juncture you grab a cuppa and hit the internet. Toyota’s online technical information is a breeze to use, and there’s really no excuse not to at only €3 an hour. A quick search for the fault code and you’ll be knee deep in information and know where to start with serial diagnosis.
Fig. 2 displays the serial data for the complete battery pack from our Prius. The eagle eyed among you will have spotted that while the battery is comprised of 28 7.2v packs. The battery management ECU is inspecting these in pairs hence the voltages around 16.X volts. So, is this one good or bad?
We’ve got some unfortunate news sir.
Toyota states that no more than 300mv difference is allowed between blocks (two packs) and as you can clearly see, the data shows an issue on block seven. But what could be causing this? Ultimately this could be down to a defective battery pack/s, alternatively it could be corroded BUS connections, as it’s not uncommon to see the BUS contacts a little green around the gills as shown in fig.3 adding an unwanted resistance between modules.
And the fault is…
In this instance, the fault is defective cells. It’s not uncommon for manufacturers to provide long warranties on their HV batteries. I’ve seen them as long as 15 years. In this instance though the battery is outside of the eight-year Toyota warranty with a new complete exchange pack available at around £1,000 + VAT from Toyota.
Until next time
There you go. A quick look at HV battery diagnosis. In our next instalment we’ll take guide you through some common HV components, their operation and key points for diagnosis. Just one thing to remember: While you’re no doubt eager to jump right in and get up to your elbows in HV diagnosis it’s worth remembering that these vehicles do offer up additional risks. They will kill you if you get it wrong, and work should only be attempted with the correct training and qualifications in place.
Need some help with your EV training and qualifications? As always, I’m here to answer your questions. If you’d like to find out how Auto iQ can help your garage with our training and consultation programs then feel free to call on 01604 328 500.
This low mileage (38,000 miles) Mercedes A200CDI was presented to us recently with suspected DPF problems. The car had been well maintained with a full service history but was lacking in power. We were asked to assess the vehicle. So, what was going on?
We started with a global scan of the car to see what fault codes were present. This would give us some direction. As always it is important we do not simply read a fault code and rely on the diagnostic tool to do the job. We were presented with three fault codes: P0299- Boost pressure of turbocharger is too low; P2263 – The boost pressure deviates from specified value; P2002 – DPF efficiency below threshold.
Direction
We now had a clear direction. The next step was to carry out some tests to determine what was causing the problem. In so many cases we see parts that are changed on the basis of fault codes. What this means is that a new turbo or DPF is fitted when in reality they are not the solution. The problem remains, at great cost to the customer.
With any low boost condition fault, we always start with a smoke test to rule out any leaks. Tests on this vehicle showed we did have a boost leak. We then looked at the DPF pressure so see if it was too high or too low. This gave us some direction. On live serial data the DPF pressure was reading zero so we could be dealing with a dead sensor or a wiring issue, or perhaps neither. We then moved on to measuring the actual DPF pressure and testing the plausibility of the pressure sensor. This was where, pardon the pun, we were really motoring. The backpressure from pre-DPF was measured at 68mb at idle. Was this the cause of the low boost problem? Was the DPF actually blocked? So why did the pressure read 0 on live data? Was the sensor dead?
We continued with our assessment to determine the answers to these questions. We then tested the backpressure post DPF. This also measured 68mb at idle so our pressure was actually coming from downstream of the DPF and not the DPF itself. This also explained why we had 0mb on live data as the DPF pressure sensor is a differential pressure sensor, not a back pressure sensor. The difference in pressure pre and post DPF was actually 0.
This model of vehicle uses an exhaust flap at the rear of the exhaust to divert exhaust gases via the low pressure EGR valve so this was the next place for us to take a look. Sure enough, the exhaust flap was seized in a closed position causing an exhaust restriction that in turn caused a low boost condition. The flap/motor was replaced and we now had a differential pressure reading of 4mb at idle with boost pressure now meeting the desired levels. No unnecessary parts were fitted. Job done!
While preparing this month’s topic, it occurred to me that a short explanation of the process behind the scenes would be helpful. All the topics I have presented here over the years have been prepared from real issues we have been presented with in our workshop. This guarantees authenticity and technical credibility.
The topic for this month is focused on a VW T5 van suffering severe vibration. I will begin by explaining that no repair authority was given at the conclusion of the diagnosis. The decision was based on a value versus repair cost and not through any disagreement. All cost was paid without objection.
The owner is a customer known to us. He often uses the vehicle for long journeys over extended distances between Lancashire and Cornwall. It was while down in Cornwall that the problem of vibration that brought the vehicle back to us began. The vibration was present with the engine running. In addition, it displayed a change in tone and reduction of intensity when full steering lock was applied.
While in Cornwall, we understand that a new alternator and power steering pump was fitted with no effect or reduction of vibration. Following this work taking place, with no change to the problem being seen, the decision was made to drive the vehicle to his regular trusted repairers. I.e, us! This was brave to say the least, and potentially teeth-rattling for the duration of the drive back up to Preston.
In an odd sort of way, the diagnostic process had already begun as the van did in fact reach us, and did not display any additional problems. Power delivery was reported as normal, suggesting that the primary rotation engine components were working normally. Our initial checks were visual with a full serial evaluation showing no reported errors. The problem appears to be mechanical in nature with no collateral influence.
Before discussing the laws of physics when applied to a motor vehicle, why don’t we explain exactly what vibration is, and how it can escalate end cost if not accurately diagnosed.
Vibration is mass energy from a source, taken through the transfer path to a respondent. Not only is this wasted energy that could be converted into traction, it will also lead to premature component failure if left to continue.
Vibration is experienced in three ways; feel, sound and sight. How we experience it depends on the amplitude and frequency. High mass energy occurs at lower frequencies and is more likely felt and heard. Low mass energy occurs at higher frequency ranges often felt and seen.
Traditionally vibration has been diagnosed based on opinion rather than evidence. So, what’s the problem? Finish reading this article then you will understand the problem and risks. Vibration can also be affected by the transfer path and respondent. For example, a high mass vibration may be amplified by a light body panel or vehicle trim.
NVH
To succeed with NVH you must first forget you are working on a specific system and focus on frequency and amplitude. The motor vehicle is a series of mechanical systems in permanent conflict, a little like a modern marriage!
There are multiple components with mass differential (weight), vector conflict (direction), frequency (speed), and amplitude (volume). The Pico NVH kit uses a three-dimensional accelerometer and microphone, or multiples of each. They convert mass into a pictorial graph, bar chart or three-dimensional topography.
The primary requirements are engine speed via the serial port or optical input, transmission ratio data, and tyre size. With this information, the software will distinguish the area of responsibility along with any collateral transfer path and respondent frequencies. Further discovery is possible by entering individual component rotation ratio, for example power steering pump.
Physics lecture over. On to the T5. We did not need to enter tyre size as the vibration was present simply with the engine running. Crankshaft data came via a Mongoose serial interface with the accelerometer mounted directly on the engine.
Referring to fig.1, the left scaling is mass in milli gravity, the base scaling is frequency response.
E1 represents the crankshaft, E2 represents combustion mass. The cursors represent the number and ratio of events corresponding to E1.You can easily see that the vibration in the centre of the graph has no relationship with the crankshaft frequency or combustion events. That the frequency is higher (lighter mass) than E1/E2. Now we need to evaluate the engine mechanical ancillaries. These are driven by a complex gear train at the rear of the engine.
Looking at fig.2, note that the tension sprocket housing a counter rotation spring arrangement. Now for the maths based on the gear train ratios; The alternator ratio 2.62:1, power steering/air conditioning 1.59:1.
Now examine fig.3 to see the revised image. E1 frequency 13hz x 2.62= 34 hz, so vibration is caused by the alternator mechanical drive system. There is a drive shaft and cush drive coupling which transfers drive to the alternator. The secondary event at 66.6hz is a respondent event, probably body vibration.
Conclusion
Now for the knockout punch! The tension gear sprocket is not available separately; in fact, you must buy the complete short engine. I seem to recall David saying it is £5,500, notwithstanding the labour cost to build and fit into the chassis. Hence uneconomic repair diagnosed without any intrusion whatsoever. Diagnostic time 0.5 hours plus the ubiquitous coffee break.
Convinced? Join our NVH training programme. Or pay me and I will come and listen to your noises.
Have you ever had a car in with a running fault or an issue, and you plugged the diagnostic tool into the OBD socket then read for trouble codes, only to be met with the message ‘no faults stored’?
For many reasons, this confuses technicians and stops them being able to progress with the job. They have no clues or starting point to work from. However, many other tests can be done to find the root cause of the issue. I have worked with many a technician who has been lost after finding a ‘no fault found’ message. I recently had a job where I was able to demonstrate to my colleague how knowing some numbers and how systems work and interlink can help identify what is wrong.
Call-out
The vehicle in question was a 2012 Land Rover Discovery 4. As we specialise in LR we have built up a good reputation in the area for being able to fix them, having also invested in dealer tooling and information. The customer’s first contact with us was via telephone and he explained he had parked the vehicle up outside his house and then having come to it the next day it would not start. The engine would turn over but it would not fire into life. He informed us his local garage had come out for a look and had been unsuccessful in finding the cause and recommended getting the vehicle recovered to us. He asked our call-out charge and asked for us to come and take a look before he organised recovery. This is not my favourite type of job as with limited tooling there is only so much you can do but we agreed to go and take and look and see what we could find.
No fault codes stored
Along with my colleague Jamie we went to the customer’s house that afternoon, taking a scan tool and the tool kit in our work van. Once we arrived we spoke to the customer to gather some information about the problem. He told us no recent work had been carried out on the vehicle and the other garage had done some basic tests on the battery and fuel system where it sat but could not find an issue. I sat in the vehicle and cranked the vehicle to verify the complaint, doing this also allowed a few checks to be done by listening to the sound of the engine cranking. A trained ear can pick up a compression issue, whether it is spinning fast enough or anything mechanical which doesn’t sound correct.
On this vehicle though all sounded ok. I then let Jamie do some checks to see what he could find. As a younger technician he mainly does MOT and general service work, so it was a good opportunity to possible teach him something along the way without the distraction of a busy workshop. After some basic checks he decided to plug in the scan took and see if any fault codes were stored. Upon carrying out a fault code report he was met with the message ‘no fault codes stored’. I then asked him what his thoughts were and where we go next. His reply was “I don’t know?” I am sure this has happened to some of you reading this article, we have all been there.
Live data
I explained to him that live data was a key element here and we should use it to our advantage. We need to look for data relevant to the complaint to rule out what it can’t be, and knowing what the numbers mean will do this quickly. Unfortunately, this takes years of looking at good data, taking notes and memorising it. Luckily for him, I was able to assist. My first checks were to be engine RPM, fuel pressure, immobiliser status, cam/crank synchronisation and a plausibility check of all temperature and pressure sensors to make sure they were in spec. Working through them all with ignition on, then cranking everything looked good so the engine should start but why wouldn’t it? This is where it pays to step back for a moment and evaluate what you know already and what you should do next.
Smoke/air pressure
An engine in its simplest form is an air pump. We know it needs compression, fuel and air to run. With what seemed to be good compression, and from what I had heard, also good data from the scan tool, with limited resources, I decided the next test would be to see if any smoke was being emitted from the tail pipes. This would show if there was any sign of fuel delivery to the engine. With good RPM and fuel pressure, if the ECU is happy, it should be firing the injectors. There was no smoke, however when I felt the tail pipes there was no air pressure whatsoever from either tail pipe. Was this a clue to where the issue may lie?
My first thought was we have a restriction and the engine cannot breathe, so we are missing the air section of the triangle for the engine to run. I then had a good visual inspection of the engine. Knowing the design well, I decided to open the inlet up to atmosphere by removing the map sensor to see if there was any change. If there was a blockage, this test would prove it and allow the engine to run. In this vehicle, the engine is a V6, so it uses a conventional V configuration. To allow air to flow into both intakes of each bank there is what Land Rover call an intake throttle manifold which also houses the MAP sensor, the EGR inlet pipework and a throttle butterfly flap with a rubber hose to direct air from the intercooler into the manifold (fig1). Removing the MAP sensor would allow air to be released if there was an issue from either EGR valve or upstream from the intake i.e. throttle butterfly, failed turbo just to name a few. On removing the sensor and cranking the engine it now fired into life and idled fairly well, this confirmed we had a blockage somewhere manifold side starving the engine of air.
Throttle butterfly flap
Checking the clock, we still had some time left allotted for the call out. I decided as it was easy to remove the intake hose to the intake throttle manifold just to see as a quick test if the issue was before or after. Upon removing the pipework and refitting the map, the engine no would not start, again proving the issue was on the engine side of the pipework. Removing the air intake plenum to the throttle manifold then revealed the issue. The throttle butterfly flap used to strangle the engine of air on shutdown had jammed shut and never reopened as the housing was heavily covered in carbon. This butterfly, when working correctly, should spring back open ready for the next engine start. Questioning the customer and his driving style revealed he mostly done slow speed and town driving and used supermarket fuel, all of which were a contributing factor to the issue as the valve sits closely to the flow of EGR gas from both valves. Forcing the valve open and refitting the components allowed the vehicle to be driven back to the workshop for a repair to be carried out.
Upon the removal of the entire assembly (fig2), it was found the unit would be better to be replaced as cleaning would not remove all of the carbon deposits and could cause the issue to re-occur. The EGR pipework was also removed and cleaned as a preventive measure along with an oil and filter change and the vehicle was returned to the customer.
Further learning
Why were there no fault codes stored you ask? Well on this engine the position off the butterfly flap is monitored and it should have stored a stuck closed fault but this may not be part of the software’s strategy so I am unable to answer why. However, this article shows that if you have an issue and no faults are stored, there are tests you can do to find the issue. So next time you have a scan tool connected, grab for example 10 good live data PIDs and store them then learn them off by heart. Once you have mastered that section move onto some more and soon you will build up a good mental library of what good data should be, which helps massively to fix cars!
By Gareth Banks
Running a garage can be difficult. There you go I said it. ‘Difficult’. No spin; no, let’s put some fluff around it and call it a ‘challenge’. It can sometimes be a down right pain in the backside.
Like you, I’ve experienced these problems firsthand, and also have the fortunate position of discussing these issues every week with those on our garage development programs. Initially a garage owner may feel like the problems they face are isolated to their business, but I’m sure you won’t be surprised to know that there is a great deal of commonality - many garages are faced with exactly the same issues.
So you get it. It’s difficult. But is there a solution? Of course there is.
Life just is
No, I’m not sitting here cross-legged practicing my Mantra, but I like that theory and it has often helped me to make sound decisions when running a garage. But what does it really mean?
For me it’s about constantly reminding myself that I’m not in control of what happens around me (i.e. what employees and customers do), all I can control is how I react. Let’s take a look at how this works in practice.
Imagine you’re a workshop manager. A technician, approaches you with a forlorn look on his face and the head of a bolt in his hand. “It just snapped” he proclaims, or “I’ve fitted that ECU and it still won’t start”, or “I’ve test driven that car for 50 miles and I still can’t make the fault happen.” Sound familiar?
It’s not just related to technical issues either. I’ll often hear a garage owner say, “I’ve lost a customer, but I’m not competing on price”. And indeed, why should you! BUT!…It’s certainly an issue that’ll need to be addressed.
As you know these daily occurrences are just the tip of the iceberg when it comes to the problems a garage has to deal with, and often seen as ‘bad’ by a garage owner. Remember however, that there is no good or bad, it’s just how it is. It’s how it is for many garages, the key is accepting this and then taking action. After all, there may be much you can’t control, but you are in complete control of the action you take.
It’s not about being good at Plan A
OK, that’s not quite right. I love a great Plan A, but I’ve gotten used to quickly implementing Plan B or C when required. In fact, being great at B and C is often the difference between stress and success. But what does all this have to do with Mastertech accreditation?
Quite simply, many of the problems a garage experiences can be largely rectified by planning to develop a technician (or technicians) to Mastertech level. Not convinced? Let’s take a look at how it’ll help.
You’d be forgiven for thinking the IMI Master Technician Accreditation was just about technical capability. It’s not. It’s about ensuring a technician is well rounded, has a wide vision of the business, and can display both technical and non-technical skills to assist with the smooth operation of your garage. Let’s take a look at the different tasks required to pass the Master Technician assessment.
Instructional support: A lot of headaches can be avoided in your garage if your technicians can teach others in the workshop as well as front of house team members. It’s this ‘on the job’ training that makes such a difference to the business in the medium and long term.
This module ensures that a technician has sufficient technical knowledge to explain fundamental vehicle systems, component operation and test procedures, then impart that knowledge as required throughout the business.
Customer liaison: Not all front of house team members has the technical ability to tease the right information out of a client, or help a client to understand why a particular technical procedure is necessary. It’s these skills in your garage that often shortens time to diagnose or placates a grumpy customer.
The module is designed to ensure that the technician has great communication skills, can assess the customers needs and deliver the information in a way the customer understands, making them feel valued no matter how challenging the client!
Technical assessment: It wouldn’t be Mastertech without the three technical tasks. It goes without saying that your garage will benefit where your technicians use a logical process; the right tools; relevant information to carry out the right tests when required; as well as know what the answer should be prior to the testing.
This module ensures a technician can display these skills, while completing the tasks in a timely manner, across different vehicle systems and subsequently document their findings. Knowledge is then confirmed in an online test prior to concluding the day.
All in all, it’s a great experience for a technician to have their skills recognised and be added to the IMI professional register, but equally as great for the garage owner to have this necessary skill set under their roof. There are also some benefits that may not be immediately apparent.
Upon closer inspection...
While there are a number of obvious benefits such as reducing misdiagnosis; vehicle comebacks; reducing workshop stress; support for workshop and front of house team and increasing efficiency, there are others that might not be so obvious.
How about staff retention? We all know how challenging, not to mention time consuming and expensive it can be to find great team members for your garage, but once you’ve found them what steps can you take to ensure they stay?
Well, from the right technicians’ point of view being allowed to take part in a training program that helps them to develop and become a Mastertech will ensure they feel invested in and therefore easier to retain. Not only that but the whole team will appreciate the reduction in stress as they now have support in the workshop, as well as with those awkward technical points at reception. It really is one of those rare situations where everyone wins. And then there’s the marketing opportunities.
Do you recall the earlier problem? The “I’ve lost a customer, but I’m not competing on price”. Having a Mastertech (or a whole bunch of them) in your garage can help here too. It’s often challenging for a garage owner to separate their business from others like it, but having a Mastetech on your team can often fix that.
If you search the IMI Professional Register for a Master Technician in your town then you’ll usually find that the register displays a number of franchised dealers and only one or two (if any at all) independent Master Technicians. This is an outstanding opportunity when communicated correctly for you to separate your garage from those in your locale, and one that the ‘right customer’ will value over your cut price competition. Now that really is a BIG win for your garage.
Decisions decisions
Ultimately, developing a Master Technician in your business is an investment, and like all good investments pays dividends for many years to come. The interesting part with this investment though is that the cost is roughly the same as visiting your local coffee shop daily. What would you rather have, a Mocha Chocha Bokka Latte or a Master Tech? The choice is yours.
As always, I’m here to answer your questions. If you’d like to find out how Auto iQ can help your team to become a Master Technicians at our IMI Approved Centre, then feel free to call on 01604 328 500.
Fig. 1
With the challenges of current vehicle engine technology, lack of access, and potential cost over value, the need for an accurate and reassuring diagnosis is vital. The technician should not allow cost or client pressure to influence the diagnosis or repair process. The ownership of the vehicle, fault, condition and repair cost is entirely the owner’s responsibility. Prior to any work, it essential that a legally enforceable agreed contract be in place.
This introduction may seem a little heavy, however it’s very likely that without a contract you may accumulate large labour cost in stripping engines to establish internal faults, then are refused agreement to complete repairs.
The answer, as is often the case, is new test techniques, training and continuing investment in technology. I recommend two options. First, a quality endoscope. Second, the Pico NVH kit.
Endoscope quality is governed by the number of optical fibres, a bright light at the boom tip the ability to articulate the mirror in multiple directions.
NVH monitoring
The next option and the focus of my topic is noise and vibration monitoring. So, let’s begin with the basics. Noise measured in decibels can be detected by changes in air pressure by three tiny bones in our ear, hammer, anvil, and stirrup. The frequency range is limited to around 20-22khz.
Vibration is the transmission of mass energy, measured with the unit gravity. It can be detected by sight, touch, or sound. There are three essential elements to vibration; 1) the source 2) the transfer path 3) the respondent.
A simple example may help; A tyre has an out of balance mass. The source, the energy, is transmitted through the road spring, shock absorber and the vehicle body. The transfer path, the dash panel, is vibrating, making it the respondent.
It is quite common to focus on the respondent instead of fixing the cause. You will have all seen mysterious weights attached to drive shafts and gear boxes. This simply transfers the frequency to a less intrusive value.
The motor vehicle is a series of mechanical systems in constant conflict. If we can identify the various frequencies across the entire operating range, we can identify the actual causes and predict potential critical failure non intrusively. Put simply we can see through metal, perhaps I should say the scope can.
Rules
Now for some simple rules. A heavy mass will always have a lower frequency than a light mass. For example, road wheel vibration, and exhaust resonance. The amplitude of vibration is affected by the transfer path, for example a light body panel, and engine block.
The distance from the source will affect frequency. Damping systems will reduce or arrest and cancel mass vibration, for example road wheel balance, dual mass flywheels, sound deadening body panels.
The next task is to separate the major vehicle components, engine rotation frequency, transmission frequency, and road wheel frequency. To achieve this, we enter specific vehicle data into the set-up wizard. Engine frequency is collected via a serial link. rotation speed divided by 60 = frequency in hz.
We can separate any frequency between 20-22khz and with a little maths relate the vibration to ancillaries, bearings, or normal generic background vibration signatures. For example, my Seat Cupra has adjustable suspension damping which totally transforms the ambient driver experience.
Environmental influences
This brings me to the next important consideration; environmental influences, the road surface, and driving style. To detect mass vibration, one or more three-dimensional accelerometers are attached to the vehicle, the location and attitude is crucial. A microphone may be added for ambient sound analysis, from this data the software will provide a choice of display options.
Now let’s look at that highly modified VW Golf R track car. The car is well known by us as we prepared and maintain it for a very proactive track day enthusiast. You know it too, as it was the subject of my article in the November issue of Aftermarket.
Producing well over 500bhp, the car boasts fully adjustable race suspension, a roll cage and Kevlar seats with trim removed. The Golf developed a severe vibration following a recent track event. The engine idles normally with no obvious problems, no noises and good oil pressure. Depressing the clutch and selecting gears has no effect.
Testing
Let’s review the images:
Many cars will be entering the Winter having been simultaneously neglected and under-driven since March, which isn’t a good combination. Now is the time to offer winter checks for your customers to see if anything is amiss.
Batteries
On the battery front, VARTA recommends garages check all car batteries before the cold weather sets in as part of their ongoing Back To Better campaign. “2020 has no doubt affected vehicle usage,” said VARTA Technical Sales Manager Andy Cook. “Many cars will not have been doing their regular journeys. Where more than one car is owned, that second or third car may not be getting used at all.
Andy continued: “Many drivers think that cold weather does damage to the battery, but it is actually heat that dramatically shortens the life-span of a battery, so by the time winter comes, older batteries are close to their limit. This coupled with many cars being parked up and not having the alternator re-charge the battery will result in higher than usual battery failures.
Andy added: “While the battery test is not part of an MOT, VARTA are recommending as part of their ongoing Back To Better campaign, garages offer a pre-Winter battery test-check to all vehicle owners whilst the vehicle is in the workshop.”
He concluded: “By offering a battery check to all customers, and replacing or giving advice on those batteries close to failure, workshops will have provided peace of mind and a reliable service to their customer base.”
Rotating electrics
Looking at the rotating electrics side, HELLA’s Senior Head of Marketing and Communications Helen Goldingay said that these parts need to be in good working order too, as they help the battery: “The starter motor is put under enormous strain, particularly when the engine is first started and in sub-zero conditions. It is, therefore, important to ensure it is correctly positioned and securely mounted in its housing. The terminal connections also need to be securely fastened and show no signs of wear or heat damage.”
She added: “The alternator is vital to ensure the battery remains well charged and able to provide the power for the engine’s electrical system. To make sure it is functioning efficiently, check it is firmly secured and that the auxiliary belt that drives it is in good condition and at the correct tension.”
Wipers
Then there’s wipers. According to TRICO, garages should definitely include a free wiper blade check as part of their winter checks offering. TRICO’s Senior Marketing Manager Sam Robinson said: “During the long, bright Summer, UV rays from the sun could have damaged the rubber of the blade, so these will need checking to ensure they’re in optimum condition.
“To assist, TRICO has compiled a checklist that they can use to assess the blade’s condition and identify if it needs replacing.”
Clean screen: Clean the windscreen using warm water or specialist glass cleaning fluid, paying attention to the areas at the top and bottom of the wipe area. Also check the glass for cracks or chips.
Safe and secure fitment: Check the blade is securely fixed to the arm. The blade should rotate freely, but there should be no wobbling or movement perpendicular to the arm.
Blade edge check: Gently clean the rubber blade edge with a damp cloth or sponge. Check for imperfections in the rubber or splits, particularly at either end. Ensure that the rubber element returns to a central position and is not flipped over and set in one direction. If the blade fails any of these checks, it should be replaced.
Wipe check: Spray the glass, operate the wipers and check that there are no missed areas, water smears or multiple streaks that impair vision. Blades that leave streaks or smears should be replaced immediately.
Sam added: “As blades are not only affected by rain and snow, but also the UV rays from the sun, TRICO recommends that wiper blades are replaced every twelve months to ensure maximum effectiveness and visibility.”
Brakes
Moving onto brakes, Scott Irwin, Head of Technical Training at Textar, said: “A vehicle’s braking system can be put under heavy strain over the winter period, with ice, snow and sleet often covering the roads. While grit can help grip, the salt can have an adverse effect on the brakes, slowly corroding them over time. Nonetheless, grit will work more efficiently should the tyre’s tread level be at an optimum level.
“However, one of the most important checks a motorist can get done over the winter is to have the brake fluid checked in their vehicle. As the fluid is hygroscopic, it absorbs moisture during its life in the car through the cap, hoses and joints that it passes. In colder months brake fluid will absorb more moisture. If the fluid is in a deteriorated state, it can cause further damage to the vehicle, such as damaging the hoses.
“The recommended dry boiling point for Dot 4 LV fluid and DOT 5.1 is 260ºC , whereas the wet boiling point for DOT 4 LV is 160ºC and DOT 5.1 is 180ºC, and this can be reduced by 30% as a result of just 5% of water contamination.”
Scott continued: “While regular servicing will check the boiling point of the brake fluid, vehicle manufacturers recommend the brake fluid be changed a maximum of every two years if not advised to before. Changing brake fluid when recommended prevents brake failure and maintains the boiling point at a safe level.”
He added: “Educating customers on the importance of checking and changing brake fluid is not only safety critical for drivers, but it also provides an opportunity for garages to upsell and create an additional revenue stream.”
Video
Once you gave performed a Winter check, you need to present the results. According to Gordon Grant, Global Sales Director at CitNOW, personalised video can help, while also give the opportunity for maintenance upselling.
“As we approach Winter, it’s vital for motorists to start thinking about vehicle health checks and general maintenance, especially if their car has been sat stationary on a driveway for long periods during lockdown.
“It’s easy to incorporate video into workshop and maintenance processes, with personalised and insightful videos created by technicians proving to be an effective method for upselling extra work, gaining quicker approval on additional recommended maintenance and delivering trusted advice to customers.”
“Firstly, the use of video can be crucial for giving customers the confidence to come back. Secondly, video is now perhaps the most important tool for managing vehicle health checks (VHCs) and presenting issues to customers. Often, this leads to increased approval rates for new amber work, or picking up pre-existing amber work that has perhaps been overlooked during the pandemic.”
Gordon added: “CitNOW is not only helping workshops book more work as a result of successful VHC videos, but is also helping to encourage customers back to the workshop and feel confident in completing work with our trusted partners.”
By Darren Darling
The challenge: A 2009 VW Golf 2.0 TDI with recurring DPF problems and no fault codes stored.
This low mileage Golf was presented to us after an unsuccessful trip to the main dealer where the customer was told there was nothing wrong with the car. The customer’s complaint was that the DPF warning light would illuminate every 100 miles; MPG was poor and the car was smoking excessively during regeneration (white smoke). As always, we carried out a thorough assessment of the vehicle to find out why the car was having these issues.
I suspected that the lack of any fault codes was the reason the owner was told that the car was fault-free but clearly we had an issue as the car should not be in regeneration so frequently. We quickly determined this was not caused by a blocked DPF as the DPF was very clean and there were no mechanical issues with the car.
Extended road test
Our next step was to carry out an extended road test while recording live serial data. If the customer had predicted correctly then we would see the DPF symbol illuminate in the next 20 miles or so. Sure enough, the light came on during the road test and the vehicle initiated DPF regeneration. This now gave us an opportunity to monitor the car during regeneration to see what was going on. We noticed that our temperatures during regeneration were too low and that the car did indeed smoke very badly.
Because of the low temperature, the duration of the regeneration was also excessive, taking over 40 minutes to complete. This is not uncommon and we have seen this caused by a software issue on many occasions. We then consulted our database and could see this exact problem with the software version so our next step was to carry out a software update and repeat the extended road test.
The car was noticeably smoother and quieter following the update but it did not initiate regeneration. Although a good sign, we had not seen any evidence yet that it had improved. So, we headed back to the workshop to carry out a forced regeneration so that we could monitor temperature, smoke and regen duration.
We were now happy with the temperatures; the excessive smoke had gone and the regen duration was back to normal. We were confident that the software update had fixed the car.
This job highlights the need for the independent workshop to invest in the correct tooling to carry out software updates because they are becoming more common. No unnecessary DPF cleaning was required to sort this DPF problem out and no parts were fitted to the car.
Another job done and another happy customer.
Would you like to get rid of that sinking feeling? The one where you fit a part and the problem still exists? If so then just keep reading
Did you manage to fit that Hayabusa motorbike engine in your smart car then? What speed did you manage to get to on your nan’s private airfield? If you haven’t got a clue what I’m dribbling on about then you obviously didn’t get your last copy of Aftermarket. Darn shame as you missed a corker.
Last time, I touched on tyres, tyre sizes, load index and speed ratings. In this issue I thought it would be only right to include tread patterns and correct fitment of said tyres. After reading this you should be able to make an educated guess about what tyre is best suited to you or indeed what is necessary for your customer’s needs and what tyres are needed in certain situations and – no, I don’t just mean if it snows then go and buy a set of winter tyres. However, I will keep it plain and simple with a hint of humour, just like myself.
Patterns
There are four main tread patterns that I’d like to explain to you. The first is the symmetrical kind. These have no sidewall markings regarding fitment and this, as you may have guessed is the same pattern all over, nothing fancy here! This one is a plain and simple get you to work and back type of tyre. It will hold the road, just as you’d expect, it will dissipate water as expected too, an all-rounder for the better months shall we say. These can be fitted on the wheel anyway you please. The second is an asymmetric pattern. Half the tread blocks for road holding and the rest are for getting rid of all that unwanted water, so this is a remarkable tread pattern engineered for the wet weather but still has very good grip for those hot summers driving through the twisties. The sidewall markings on these tyres are ‘inner’ and ‘outer' or ‘inside’ and ‘outside’. They are designed to be fitted only one way.
The third in the list is a rotational tyre. This is clearly visible by the sidewall markings that have an arrow stating a certain way the tyre must be fitted. Please be careful and remember it is a MOT failure if a tyre Is not fitted in accordance with the sidewall instructions. This type of tyre will also have a tread pattern that looks almost like a continuous arrow pointing in one direction. This tyre is exceptionally good at dissipating water, as you drive through the wet roads water is drained away from the centre of the tread and ejected outwards to prevent aquaplaning.
Winter
“But what about the fourth one?“ I hear you cry. Well, this one is a winter tread pattern, recognisable by the unique three peaks’ symbol. These tyres will more than likely always be rotational with sidewall markings displayed with an arrow. They are characterised by the little wiggly lines in the tread. The real name for these is sipes, and these are designed in such a way that they increase the tyres surface area on the road and this in turn creates more traction.
Winter tyres are engineered with more natural rubber within their compound. They actually stay more supple for longer in lower temperatures. This helps with traction in ice or snowy conditions. However, a winter tyre will only outperform a summer tyre in temperatures of 7°C or lower. Now, there are no laws in our country to say we need to fit winter tyres in the colder months, yet. That said, I can see it on the cards in the future to prevent more accidents. Also, a few customers have seemed to feel a little uneasy when it comes to their insurance and winter tyres. If you’re unsure, just check with your insurance company, you will find that more and more insurance companies find them to be a valuable asset to your car in the colder months and will probably welcome such a safety conscious driver into their realm.
It’s not often you get two bites of the same cherry, but in my case, it happened just one week apart. The story begins many months ago with one of our regular customers. The customer in question is a real enthusiast and a keen track day driver. His car of choice is a Volkswagen Golf R.
Having modified the car over several months, we now have a 500 BHP-plus Golf. It has KW variant 3 suspension with Eibach roll bars, a floating brake disc upgrade, and lightened shell, roll cage etc. It also employs a MBQ electronics platform. I could continue but I think you get the idea.
It’s fully fettled, but even with the best kit and care, you are bound to have something go wrong eventually. Can you guess what happened? That’s right, a problem occurred!
Lack of power delivery
During a track session the car suffered a lack of power delivery, with no abnormal symptoms, misfire, oil consumption noise or vibration.
The Initial investigation began with a serial scan with no DTS present. It is at this point a diagnostic strategy should be put in place. The phrase ‘first look’ involves the principle of gathering as much information without intrusion as possible.
Where to start and which option to take depends very much on the symptoms. In my case the initial tests were conducted in my absence.
A full load data log indicated a specified and request turbo boost pressure of 2.8 bar absolute, with an actual value of 2.3 bar indicated. These values will no doubt illustrate the level of modifications to the power train. The car still delivered a powerful drive experience although the actual power experienced was less than expected.
Well-established test process
This is a common problem and with a well-established test process. The charge pressure circuit was pressure tested without any external leaks. Because the en888 engine does not employ an EGR valve, we did not believe that the cause could be the result of internal leaks. Our first idea actually pointed towards the hybrid turbo, which we initially suspected as the prime cause of the ailment.
I was asked to call into the workshop to review the results so far. I suggested a NVH in cylinder profile be conducted. This engine employs variable camshaft timing on both cams with lift extension on the exhaust cam. With this in mind, I was especially interested to examine the valve piston relationship and the valve pocket profiles.
The results immediately confirmed significant errors to the intake and exhaust valve pockets with excessive exhaust pressure. This engine variant should have little or no pressure above 1 atmosphere, or 1,000mb. during the exhaust stroke, my test results confirmed over 1,700mb absolute. Valve pockets represent the pressure differential across the four-stroke cycle and accurately represent the mechanical efficiency of the Otto Cycle. This is often referred to as pumping losses. So, we have a restriction in the exhaust stream, turbo, catalyst or exhaust system? Removing the flange pre-catalyst enabled examination of the turbo hot side and catalyst intake.
Reduction of boost pressure
The catalyst substrate was detached and turned through 90 degrees. In this way, we discovered the symptoms. A restricted exhaust was reducing both air intake volume, therefore load calculation, and turbine volume. The result was a reduction of boost pressure.
Next, we needed to discover the cause. Excessive heat and expansion, followed by the catalyst detachment. This was interesting, not least because a recent upgrade to the fuel priming system resulted in the fitting of an upgrade in tank pump. The result of which only became known after a track session where a drop-in top-end power resulted in a DTC rail pressure negative deviation.
The pump module, a specific upgrade from a respected independent VAG tuning specialist, had been supplied with the incorrect o ring. This resulted in a slight drop in both flow and pressure together with cavitation causing a lean mixture ratio at extreme load.
So now we have the complete trio, fault, symptoms, and cause.
Happily ever after?
That is not the end of the story however, as this particular VW Golf R returned just a week later. The good news was the owner’s report of exceptional performance. However, the bad news was that with the returned power came horrific vibration.
That’s a story for another day though.
Tyres; the little black miracles that keep us and our precious cargo glued to the road. There is an awful lot to write about within the subject of tyres: sidewall markings, pressures, TPMS, tread patterns, puncture repairs, the rules on mismatched tyres on a four-wheel drive vehicle.
This is why my article on tyres will be split into two parts. However, something told me that for this issue we should go back to basics and by back to basics I don’t mean as basic as the minimum tread depth for a car tyre. 75-year-old Ethel who doesn’t drive now can tell you that. No, I mean the bits you think you know and the bits you need to know as a technician, as a MOT tester or as a centre manager selling your “diamonds” as I’ve heard them referred to in the past.
A jeweller knows all about the product he/she works with and sells. They know that the most precious and expensive diamonds on their shelf were probably mined in India, Brazil or South Africa and made from pure carbon. If it’s a synthetic diamond, it was probably made in a factory in Birmingham. In that respect would it hurt to learn a little more on the subject of tyres.
Let’s begin with the three sets of numbers on the sidewalls of your tyres. The first three-digit number is the width of the tyre in millimetres, the second two-digit number is the height of the sidewall and this is expressed as a percentage of the width of the tyre. Next, we have the size of the wheel that the tyre in question should be fitted to. Then we have the load index of a tyre, this will be located after the rim size, this is the maximum weight that the tyre can carry and this is expressed in kilograms. For example, if the load index number is 84, it means the tyre in question can carry a maximum load of 500kg, whereas a load index of 108 could carry a metric ton all by itself. There are obviously many more load numbers to comprehend, these were a few examples.
Beside the load there will be a speed rating, now. I have no idea why most little cars have a ‘T' rated tyre fitted to them (safe up-to 118mph) or even a ‘H' rated tyre (tested up-to 130mph) fitted to them but it seems the norm. However, considering that a lot of these cars cannot even get to 100mph it seems like a waste, especially when it is illegal to drive your car over 70mph on our roads, even in other countries where the majority of tyres are made, most speed limits don’t exceed 80mph.
There are exceptions to this of course. Maybe one of those nutters who puts a motorcycle engine in a Smart car and make it go 160mph for example. That’s all well and good, but you’ll never find a tyre for a Smart car that will handle that kind of speed, plus if you like driving at more than 160mph then you have no regard for rules anyway. Please do not put your ‘T’ rated tyres on your homemade Smart-bus and take it to the Isle of Man or indeed your gran's private airfield for a play. If you do please send me the video though. I do love things like that, but I also like safety too.
People ask me what made the difference this year when I went from being a Top Technician finalist to a Top Technician winner, and my answer is my process. I have worked hard since last year’s final, refining my process, and learning from my mistakes and it thankfully paid off this year. This article highlights the importance of a great process not only in Top Technician, but also in everyday working life, and how a fault, which at first may seem overwhelming, can be simplified and confidently fixed.
The week after winning Top Technician, a 2016 Ford Ranger was booked in for me to have a look at from another garage. The garage’s complaint was that multiple warning lights were present on the dashboard along with multiple warning messages, the power steering was heavy and the indicators and windscreen washers didn’t work from their respective stalks.
As with every job, the first step of my process is to interview the customer and gather as much information as possible. When I questioned the garage owner, he said they had just completed fitting a galvanised chassis. He explained that the vehicle had been fully stripped and rebuilt in the process, and since the rebuild, warning lights, messages and other complaints were now present. The next step was to confirm the fault. Upon starting the vehicle to bring it into my bay, the complaint was verified. The engine management, traction control, anti-lock brake and airbag warning lights were illuminated along with multiple different messages, one of which was a steering assist malfunction warning (see fig. 1).
Complete picture
I then carried out a global scan of the vehicle to get a complete picture of what faults were present and also to see what modules were or were not talking to the scan tool (see fig. 2).
Straight away we could see that multiple modules could not communicate with the power steering control module (PSCM) and restraints control module (RCM). It was also noted that there was a communication issue between the body control module (BCM) and the steering column control module (SCCM).
As the instrument panel cluster (IPC) communicated and reported stored fault codes, I knew it was more than likely a historic fault code which wasn’t related to the issues present. Attempting to communicate directly to the PSCM, SCCM and RCM with the scan tool all returned a ‘no communication’ message, so we knew we were dealing with hard faults that were currently present. Following my process, I decided the next step was to do some research on this particular vehicle using Ford ETIS which is Fords online information portal. This allows me to access wiring diagrams, connector locations and anything and everything related to the vehicle in question. As many a clever man has said, “if you don’t know how it works how can you fix it?”
Thinking of possible causes, I decided to study the wiring for the PSCM and RCM, how the indicators and windscreen washers work and a network topology to allow me to see how all the modules communicate to each other and the diagnostic scan tool.
It was found that the steering column module controlled the indicators and washers and sent the message to the BCM to activate them. As the SCCM wasn’t communicating it now made perfect sense why those functions were not operating. Next, I found that all three modules worked on the high speed can data bus and all were powered by fuses. All the related information and diagrams were printed out and taken to the vehicle so that a test plan could be drawn up and executed.
Plans within plans
Before writing up my plan, I made a visual inspection of wiring under the bonnet and underneath the vehicle. Having had a major overhaul, something as simple as there being a connector left unplugged could cause some of if not all the faults present with this vehicle. Everything looked ok, so I laid out my wiring diagrams and proceeded to write a plan. My plan was to test the fuse for each of the modules to see if it gave me direction, then if all was ok I would look at the communication wiring and how the modules at fault linked into each other and the rest of the vehicle.
All three fuses tested fine so it was onto seeing if there was a common link. Looking through the topology, I found a page which had the PSCM and RCM joined by two connectors. This is where technical information is a must, as dealing with a fault like this it can be very easy to dive in full speed. I don’t want to go straight to a module, for example the RCM, and remove half the interior of the vehicle to find all is ok there and have to spend time reassembling everything! I speak from experience here, and I am sure some of you reading can relate to this.
Diagnostic direction
ETIS showed one connector inside the nearside front wheel arch and the other in the location of the bulkhead of the vehicle. This meant I could test the network without removing anything, saving time and gaining diagnostic direction. I inspected visually to see which of the two connectors was the easiest to access and it was the connector in the nearside wheel arch. Visually the connector looked correct and looked to be correctly latched. However, I decided to double check and upon squeezing the two sides together and audible click was heard meaning the connector was open (see fig. 3).
I then decided to scan the vehicle again to see if this had made any change and every module now communicated and it was also noted the dashboard warning lights had disappeared. I cleared all the faults codes in the vehicle. None returned, and the dashboard now had no messages or warning lights illuminated. The final checks proved the steering assistance now worked correctly and the indicators and washers operated completing the fix.
In the end then a fairly simple fix once it was established how the system worked and where everything was located but without the correct information and a well polished process this job could have taken a very different, and perhaps longer, turn.
By Darren Darling
The JLM Diesel Intake Extreme Clean Toolkit Pro is always to hand in my workshop. The first vehicle we tested it on at the pre-launch stage was a Seat Leon with severely sticking turbo vanes that were causing instant limp mode due to turbo over boost.
The owner had tried a leading brand of turbo cleaner via the intake but the problem was still there. After data logging we could see there was a major issue. Two hours later and using the Diesel Intake Extreme Clean Toolkit Pro there was no limp mode and normal boost logs. We also tested four vehicles with sticky turbo vanes that were data logged before and after the treatment. On three of them the boost levels came back into spec and out of limp mode.
The other vehicle required a new turbo as it was past the point of no return. Sticking turbo vanes are a common problem on modern vehicles due to a build-up of carbon. Since then we have saved dozens of cars from the scrapyard including a taxi that had failed the new smoke test with the same results despite being fully serviced with a new DPF filter. After treating it with the kit it passed the retest.
With regards to DPFs, the most common misconception is that a DPF showing as faulty is faulty when more often than not it isn’t. It doesn’t require a clean or worst still a replacement which can cost a lot of money. For example, I was asked to clean the DPF on a Ford Transit and replace a faulty temperature sensor. Upon inspection the DPF was clean and the faulty sensor was actually a broken wire so no parts were needed. It can be tempting to blame the DPF when in fact it is a symptom of another problem.
We use the full range of JLM DPF products and one in particular; the Professional Cleaning Toolkit is a real hero product. You can clean a DPF in two hours without removing it. A mechanic who has been turning DPF business away or outsourcing it can keep the DPF business in house thanks to this world class kit.
Many of the DPF doctors in our network choose JLM’s DPF cleaning products because they are effective and because the low temperatures during cleaning make them much safer than cleaning at high temperatures.
The JLM Diesel Extreme Clean is a product that’s used daily in our workshop and we’re seeing the same great results with the petrol product, JLM Petrol Extreme Clean. It’s the answer to late model cars and engines with severe build up and blocking problems in different parts of the fuel system. These contaminants are tough and not easily dissolved with regular fuel additives. The JLM blend comprises multiple super power additives packaged into a highly concentrated 500ml shot for one tank treatment.
Delivering fantastic customer service is an obsession of mine. This means there’s no wriggle room when it comes to the products I use in my workshop. I can only use world class products that have been designed, developed and manufactured for the professional motor mechanic; products that work on the most challenging vehicles – vehicles that have often been misdiagnosed elsewhere so it entails starting from scratch. With JLM Lubricants I have a powerful ally.
By Gareth Banks CAE AMIMI
I like to think I have some good experience under my belt in various aspects of the industry, from working as an apprentice in 2002 in a little backstreet garage to working in a bodyshop to being a breakdown mechanic to where I am now.
I have probably learned more in my last three or four years than at any point in my career, especially when I get to work with (i.e. pester) Martyn, our mobile master technician. One of the things I’ve learned from Martyn is the importance of doing things correctly and also the importance of servicing correctly. I’ve found to be a good mechanic you almost certainly need to be a perfectionist, or at least vaguely resemble one. This doesn’t mean working superficially for hours on one small job though, checking the tightness of one nut constantly. No, it simply means doing things the right way, putting a smear of grease on a fuel filter seal. It means not just replacing a clutch when there is also a DMF hiding in there too.
I still service cars even though my main job title is MOT Tester. I did like my previous job as service technician, but that being said it is one if the dirtiest jobs in a garage. You can be as careful as can be, yet still go home stinking of Shell’s finest.
Anyway, coming back to the point – servicing. We are back with our friends at Bob’s Autos to look at the importance of servicing and the implications of not doing a job right.
One lady owner
One day at that garage, in a place you’ve never heard of, a car comes in for a full service. There is also a warning lamp on the dash. The customer (a lovely old lady) explains that it’s only been 3,000 miles since last service. Before he starts, Fred – Bob’s main man, plugs his scanner into the car in the hope that the car will magically tell him what’s wrong. Sure enough a p0522 fault code is present; ‘low oil pressure’. Both Fred and Bob are scratching their heads.
“Delete the fault code and carry on with the service” says Bob. Reluctantly, Fred continues after hearing his boss’ forceful advice. With the lights check complete, a battery check, coolant check and his brake fluid check done, he raises the car up, drops the engine oil and moves to the oil filter itself (paper element type). The cap is a little tight coming off (one of those you think may have broken when it cracks loose), half the filter comes out, with the other half still stuck at the bottom of the housing, all sodden and saturated, broken into pieces in its own dirty oil. With a few swear words uttered under his breath Fred turns to his boss and simply says “well this hasn’t been changed in a month of Sundays has it?”
But like the customer said when she brought the car in, it was only done a few thousand miles ago, supposedly. Fred doesn’t actually remember the car. He was away with the family when it was done. This only leaves one man – the culprit. Bob knows he didn’t replace one of the most vital parts during the service, but he won’t ever say anything. He knows he caused all this trouble, starving that poor little engine of its oil. You wouldn’t starve a human of water would you? Well, Bob might, if the water cost a few quid.
It’s a real shame that people like Bob exist. I’ve seen many cars in my 17 years of working in this industry come to me with similar issues, and you can just tell that some talentless, cheap cretin like Bob had their hands on the car you’re working on. All we can do is rectify their cock-ups and hope that the customer has more trust and faith in you than the last place they went, thus keeping your client base up, keeping people talking about how much they trust you as people. As a garage, do not be a Bob. Bob sucks!
When this 2010 Vauxhall Insignia arrived at our workshop recently, we were asked the common question: “How much to clean my DPF?” As always, we informed the customer the first thing we needed to do was to undertake an assessment, so we could determine why the car was having DPF problems and what was required to fix it. This assessment is much more than a fault code read, often perceived as a ‘diagnostic check’ and this highlights the difference. The fault codes present on the car were ‘P2453 DPF Pressure Sensor A Circuit Range Performance’ and ‘P2458 Mass Air Flow Sensor Performance’.
Opening the bonnet, we were not surprised to see a new MAF sensor and a new DPF pressure sensor. This is frustrating as the owner has paid for these unnecessary parts to be fitted on the basis that ‘the computer said they were faulty’.
Looking at the DPF pressure sensor fault first, the ECU was reporting a circuit range fault. This may look like a faulty sensor but is in fact caused by excessive DPF pressure. The pressure is measured by the sensor. The signal is sent back to the ECU as a voltage so the excess pressure causes an excess voltage signal and in turn the ECU reports what it can see. The DPF back pressure was in excess of 150MB at idle indicating we must clean the DPF after addressing the cause of the problem.
Moving on to the MAF performance fault. Again, the ECU only reports what it sees as incorrect; in this case incorrect air flow. This is obvious when analysing live serial data so our next step was testing the intake system for leaks to confirm our suspicions. As you can see there was a significant leak from an intercooler pipe. We found a cause for both issues. The split pipe would have initially caused the MAF fault but in turn would lead to the DPF pressure sensor fault due to the excessive soot being produced with the major boost leak.
After consulting the customer, we repaired the car, replacing the intercooler pipe. Root cause now taken care of we had the easy part – cleaning the DPF. Our weapon of choice for DPF cleaning is always the JLM Lubricants’ Clean & Flush. With the step one chemical we left it to soak for a few minutes. After running the engine for a few minutes, we flushed the DPF out with the step two JLM DPF flush.
After the clean we had a healthy 6MB of back pressure in the DPF and the pressure sensor fault was cleared. An extended road test confirmed the fix.
Let’s face it, it’s a problem. It’s a problem that has existed for too many years. In fact, the solution to this day eludes so many intelligent garage owners. It’s the perennial problem. What is this enigma? What’s one of the most common questions I hear on our front-of-house training courses? Quite simply the question I’ve been hearing for decades is this: “How do we charge for diagnostics?”
To add insult to injury the cause of this problem is another question. It’s a question your front of house team will hear every single day from your prospective clients. It goes a little like this: “How much does it cost to…” turn a MIL light out, diagnose my DPF fault, solve a lack of power, diagnose a non-start, etc. It’s endless, the question keeps on coming and you definitely need to answer it. Why is answering this so important to your business? Let’s take a look.
While we’re talking about questions I’ve got one for you. Do you charge for all of your diagnostic time? If not, How much income do you lose to time not charged? If the answer immediately sprang to your lips then well done for having a monitoring system in place. If not then you might be surprised by the size of the problem.
I’ll err on the side of caution with my estimate but, if you have a workshop with four technicians and two of them lost half an hour a day to non-charged ‘diagnosis time’ (assuming your labour rate was £65 per hour) then that would be costing you £14,950 a year.
As a side note, it blows my mind to think how much revenue has been lost to this problem over the years across our industry.
Now, I’m sure if we’re honest with each other and we documented all the ways that this time disappears from your bottom line then you’d agree the problem is probably larger.
The BIG question is would you like to fix it? Of course you would, and here’s how.
Before we get to the answer let’s consider what our endgame is. From my point of view it’s simply this; The solution needs to be fair. Fair to the garage owner, fair to the customer and fair to the technician. What does ‘fair’ look like? I’d consider fair to be:
The vehicle battery has for many years ceased to simply be a chemical storage device. Instead, it has turned into a critical integrated component within the electronics network. It is also increasingly responsible for the total electromotive force in electric vehicles. I will comment on this development later. Despite this, it remains little understood or respected by many techs. I will begin with some interesting technical facts, provided by Yuasa, our battery partners here in the UK.
Many independent battery manufacturers limit the critical internal components to reduce cost, as well as to maximise profit and range application. Typical configurations include smaller cell capacity and increasing the electrolyte strength to artificially meet CCA ratings.
Reducing lead content reduces reliability, specification, and lifecycle. The electrolyte has a direct effect on performance and lifespan. Increasing electrolyte strength to artificially meet capacity specifications will increase internal corrosion.
The end of life is directly affected by the number of start cycles over time, this is the defining feature of 2/3/4/5-year battery construction. The battery begins its decline immediately following manufacture. The initial formatting drives impurities off the plates, as a result the peak CCA performance should be achieved. The peak performance period (lifespan) depends on its warranty specification. The final phase is a rapid decline in output and eventual failure. The correct action is to replace the battery before the final decay period, it often appears to perform normally during this period.
Hands up, who checks batteries at the point of delivery? If they are below 12.4v send them back. Six cells at 2.12v produce a voltage differential of 12.72 fully charged. At 0°C a battery has 66% available capacity. Excessive heat can also have a negative effect on battery performance and accelerate failure and end of life due to plate corrosion, an increased in self discharge, and increased electrolyte loading. A 10°C rise in temperature will increase the self-discharge rate from 0.1v to 0.2v per month.10°C equals a 60-month battery life. 25°C equals a 36-month battery life.
Plate sulphation is normal during battery discharge. When both plates are coated with lead sulphate, or when the plate voltage falls below 12.4v, prompt recharge will displace the lead sulphate. The battery will normally recover and perform normally. However, if allowed to stand it will crystalize and harden.
The death zone of a battery rendering it unrecoverable is SG at 1.04, cell voltage at 1.9v, total battery voltage at 11.3v.
Recovery is marginal from a SG at 1.02, and a battery voltage at 12.3v. Acid stratification accelerates failure and can occur due to cold weather and short drive cycles. The separation of acid has the effect of increasing the open circuit voltage while reducing the CCA performance. Superficial testing may show a healthy fully charged battery.
Conventional flooded batteries should be maintained within 5% of its fully charged state if premature cell failure is to be avoided. Meanwhile, AGM batteries can operate normally with a 50% cycle rate.
24v systems and vehicles using two batteries require that both the CCA and OCV be in balance. This is also a critical factor with electric vehicles using lithium batteries, as cell differential will lead to differential cell charge and overheating.
Stop/Start vehicles will be fitted with either an enhanced flooded (EFB) or absorbent glass matt (AGM) batteries. Key differences with EFB & AGM are:
The vehicle repair world can be hugely satisfying one day and an absolute pain in the backside the next. The challenges we now face as techs are getting harder and more detailed thanks to the electronic minefield of modern cars.
There have been a few instances in the workshop where we have had to admit to the customer that we just aren’t sure yet what is wrong with their car. It is mostly met with understanding as we explain the complexities, but on the odd occasion it can cause the customer to become annoyed.
Last week we had a BMW 1 Series come in. The customer had been elsewhere to get the fault codes read as the car kept going into limp mode. It had shown a fault linked to the crankshaft sensor. They requested that we changed the sensor and check the wiring.
The crankshaft sensor is under all the air intake manifold and isn’t the easiest of jobs. Wiring was all deemed to be ok and a new crankshaft sensor fitted. The car drove great, then a week later same problem reoccurred.
So, it came back, again, and the car was hooked up to a diagnostic computer and faults relating to a pressure sensor and the catalytic convertor came up. As we deal with a lot of older and classic cars we aren’t trained in electronic fault diagnosis. It is not only frustrating for us to not be able to help the customer but also for the customer who keeps having to bring the car to a garage and not be able to get the fault rectified.
That is the way car repair is now heading. It is a lot more computer-based with a lot less instinct and hands-on work. Hours can be lost testing all the wiring and sensors on a car. It is hard sometimes to justify a bill when you have been unable to locate the problem. As car problem fixers, mechanics pride themselves on being able to hand a vehicle that came in broken and goes away running perfectly. That is why we do this job - to become heroes in the eyes of the customers. The BMW owner is now fed up with the car. It has been to different garages and specialists who have been unable to completely fix the problem and they have fallen out of love with the car.
In my experience if an issue isn’t easy to fix we have to be completely honest with the customer, I often explain that we don’t have the up-to-date software that would give us the definitive answer. We then recommend a reputable specialist that would be better suited. As a business owner I am here to fix cars but I am not about to pretend we are something we are not. I know how capable the staff are and what our limitations are. Yes, it is frustrating turning work away but it is also important to be completely upfront with the customer.
There are already over 620,000 battery electric, plug-in hybrid or conventional hybrid vehicles on UK roads. This will only rise, with manufacturers set to dramatically increase production of these vehicles over the coming decade.
Therefore, it’s surprising many garages still don’t have the skills or tools to safely service them. However, Adam White, Director of Workshop Solutions at Euro Car Parts, says there is plenty of help available that can enable technicians and workshop managers can catch up: “Volvo Cars has just signed a multi-billion-dollar battery deal through to 2025, signalling a strong commitment to electric and hybrid vehicle production. In fact, its battery order is so large, it’s more or less equivalent to the entire global production in 2018. This means by 2025 half of Volvo’s global sales, some 500,000 vehicles, will be fully electric. At the start of this year, Ford announced a $15 billion investment and 40 electrified vehicle models by 2022. BMW Group plans to offer 12 full-electric models by 2025. The list goes on and the point is clear, vehicle manufacturers are investing heavily in hybrid and battery electric vehicle technology and it is time to follow suit.”
Adam continues: “The biggest threat to the independent aftermarket is also its greatest opportunity. The greatest risk during this period of transition is that independent workshops slip behind, and customers have no option but to service their vehicles at main dealers. While we see some switched-on garages and younger technicians getting involved with hybrid and EV training, we have a significant amount of data showing a serious industry-wide deficiency in hybrid and EV knowledge and skills.
“Many garages do not see the required investment in training or equipment as worthwhile, believing there to be very few of these vehicles on the road. White suggests the numbers tell a different story. Industry predictions suggest a short-sighted approach to the hybrid and EV market may be damaging to workshops in the long term.”
While optimistic about the aftermarket’s ability to adapt, Adam cautions workshops to approach the opportunity with the right frame of mind and an awareness of the dangers involved with high-voltage systems: “While the risks of working with hybrid and EV vehicles can be safely mitigated, much like conventional vehicles, safety training is critical. For those wishing to test the waters, technicians can be taught how to make the vehicle safe, without the more intensive training on servicing the actual high voltage system. This means if a workshop has one or two technicians who can isolate the vehicle, the rest of the team can safely work on other systems like steering and suspension or air conditioning.
“Many workshops are turning away hybrid vehicles, even when the problem is unrelated to the high-voltage system. While this approach may be sustainable now, we’re at the turning point. Even if workshops aren’t willing to completely commit, having a few staff qualified to make the vehicle safe opens other servicing opportunities. Those who start working on hybrid and electric vehicles now will be ahead of the curve, gaining customers, experience and a reputation for the work. It could be a make or break difference in the coming decade.”
Training
Commenting on training available, Adam says: “Auto Education Academy, Euro Car Parts’ dedicated training platform, offers several appropriate courses, including GED 13 – an IMI Level 2 Award in Hybrid Electric Vehicle Operation and Maintenance. The course teaches technicians how to maintain and repair hybrid vehicles but not the hybrid or electric powertrain itself. Technicians learn about the dangers of high-voltage systems and the differences between HEV, PHEV, EREV and EV. It also covers the various approaches used by manufactures to power down the high-voltage system and the safety equipment required.
“For those looking to repair and replace hybrid vehicle parts, a more detailed and comprehensive course is required. GED 14 is an IMI Level 3 Award in Hybrid Vehicle System Repair and Replacement, giving technicians the skills and knowledge to effectively service and repair EV and hybrid systems. This course lays the foundation for further advanced training. Both courses can be booked through Auto Education Academy.
“It’s free to join, and repairers can login to their own skills portal to view the content of more than 75 different courses. Users can also assess their strengths and identify weaknesses in nine key areas; petrol engines, diesel engines, engine management and emissions, vehicle electronics, air-conditioning, brakes, powertrain, tyres, steering and suspension, as well as hybrid and electrical cars. Results are automatically added to an interactive skills diagram; which technicians can compare with the national average to gauge where they stand.
“Users can see for themselves the serious hybrid and EV knowledge deficiency that exists within the UK. Anyone can go online and complete the skills overview; it’s a great way to understand your personal strengths and weaknesses. It can be a useful tool for managers looking to assess the core competencies of their staff or potential new hires. The data we have suggests knowledge about hybrid and electric vehicles lags far behind other core areas, a growing concern we hope to change.”
Accessible online or over the phone, it provides fast responses to troubleshooting, repair, diagnostics and technical information queries on any vehicle, from any manufacturer.
Workshop Solutions offers four safety equipment packages for workshops working with electrified vehicles. Workshop Pack, Vehicle Safety Pack, Personnel Safety Pack, Safety Tools Pack. There is also a Hybrid Master Safety Pack (£1,099), which includes all four of the above.
“I can understand the trepidation and hesitation we are seeing across the aftermarket,” concludes Adam. “Repairers are focused on looking after their current clients and building a business around what they know. However, things are changing, and we have a widening gap between vehicle technology and skills within the aftermarket. We need to address this shortfall and capitalise on the opportunity hybrid and electric vehicles present to the independent aftermarket.”
The growth in electric and hybrid vehicles is having an impact on many systems that mechanics are, or at least think they are, familiar with. As the segment grows, techs may find they need to re-learn even more than ever before.
Dr Liz Dixon, Global Technology Director of the Shrieve Group, a supplier of synthetic speciality refrigeration lubricants, comments: “Polyalkylene glycols (PAGs) are the lubricant of choice for hybrid and electric vehicle air con. The hybrid/electric vehicle market is growing rapidly and driving up use of electric air-conditioning compressors, and environmental legislation is leading equipment manufacturers to use more environmentally friendly refrigerants.”
European directive 2006/40/EC fully came into effect in 2017. It stipulates that air conditioning systems in motor vehicles type-approved after 1 January 2011 may not be filled with fluorinated greenhouse gases with a global warming potential (GWP) higher than 150. Compliance with this directive led to the development and adoption of R1234yf, which has a GWP of 1.0. In addition to this, R1234yf has a low ozone depletion potential (ODP). Developed to be a drop-in replacement for R134a refrigerants, R1234yf is now the industry standard for new vehicles and r134a is being phased out.”
It’s not all good news though. “Unfortunately,” says Dr Dixon, “the R1234yf chemical structure that ensures a low GWP can also cause issues with refrigerant stability. To counter this, the right lubricant is vital for long-term operation. So, how do you select this lubricant? Fundamentally it boils down to chemistry.
“R1234yf’s molecular structure causes a high level of chemical reactivity. The lubricant must have the correct stability properties to counteract the refrigerant’s inherent reactivity, in addition to appropriate miscibility properties with this new refrigerant type. In this regard, PAG lubricants have the most preferential properties. Electrical systems require further considerations of the lubricant’s conductive tendencies:
“The reason many PAG-based solutions have exhibited such electrical properties is because of how they are formulated and processed. If these PAGs are processed under more stringent conditions to achieve higher levels of purity, you get less contaminants, and a resultant lubricant that is perfectly safe for use in hybrid and electric compressor systems.”
Two in one
On the engine side, for the increasing number of hybrid vehicles, LIQUI MOLY has produced a new additive. David Kaiser, who heads the R&D department at LIQUI MOLY comments: “Strictly speaking, the Hybrid Additive is itself a hybrid, because it combines two properties. It stabilizes the fuel quality and it cleans the injection system. In hybrid vehicles, the electric motor is the main drive. Meanwhile, the combustion motor works only as an assistant. This engine is mostly only used for short periods. This results in two problems.
"First, the fuel remains in the tank for longer and ages more, compared to vehicles powered exclusively by a diesel or petrol engine. The second problem is deposits in the injection tract because of the irregular short-term use. The Hybrid Additive keeps the petrol quality stable, protects against deposits in the injection system and removes existing deposits. It therefore solves both problems. The LIQUI MOLY Hybrid Additive is only for hybrid vehicles with a petrol engine.”
Picture this: You’ve a mildly grumpy client stood at your front desk. We’ll call him Mr Brown. He has been a happy customer for many years, you’ve serviced his vehicles regularly and all has been good in the world.
Unfortunately, today is Mr Brown’s third visit to your counter for the same problem. He’s understandably becoming irritated by the fact that your technicians aren’t able to identify the reason behind the intermittent loss of power with his VW Golf, and he’s starting to doubt the competency of your business.
It’s a common problem, so your garage should have a robust solution. If not, then you could lose Mr Brown's custom. See this happen too often and it will put a major dent in your bottom line. Nobody wants that.
Is there a solution to the intermittent fault dilemma? In many instances yes. You just need to apply the right routine. With the right routine, tools and information you’ll dramatically increase your chances of finding the fault in the first go. Apart from keeping Mr Brown happy, your techs will enjoy the buzz of early diagnostic success. The big question is what needs to change in your garage to improve your chances of nailing these elusive faults? A look at Mr Brown’s vehicle will show a pattern that you can use in your garage.
Mr Brown’s Golf has been experiencing a sudden loss of power. It makes him pull over to the kerb. Stopping and starting can make the problem disappear and not occur again the same day.
The vehicle has been scanned and road-tested on both visits. A fault code relating to rail pressure deviation has been recovered in both instances, but no fault was found on the multiple road tests completed. What can you do to get to the root cause of this problematic situation? Just use this routine:
1: Thorough grilling at front desk
We find the following statement usually has a client bending over backwards to help: “Sir – It would be great to speak, if you have a few minutes, so that I can find out some specific details of the fault on your vehicle. We often find that a few minutes of your time now will often help us find the issue and could save you money on the cost of your diagnostic evaluation.”
All you have to do now is ask the right questions to ascertain a point at which something changes on the vehicle and the details around that, as well as some specifics as to when the fault occurs.
In this instance further questioning revealed that the problem normally occurs around a mile or so from Mr Brown’s home, after he’s started his journey in the morning and occasionally on his way home.
Armed with this information, you give Mr Brown a courtesy vehicle so that you can carry out the tests the next day.
2: Where did I put that silver bullet?
We’re already one step closer compared with previous visits, and have a constantly recurring fault code for high-pressure control deviation. Initially, it’s worth making this the focus of our diagnosis. For starters you could take a look in ELSA (where the VAG group keep their silver bullets) for any known issues in their service bulletin archives.
You find one relating to a known mechanical fault for the high-pressure pump wear resulting in constantly low pressure, but nothing for an intermittent fault such as yours. To be on the safe side you inspect the known issues and find the connection between the camshaft and the high-pressure pump to be in good order.
3: Desk diagnostics -Where the magic happens
It’s in stage 3 where the magic begins. You need to make an exhaustive list of the reasons that could raise this fault code:
A Restricted supply to in-tank pump
B Faulty in-tank pump
C Power/ground supply fault to pump
D Faulty low-pressure fuel pump control module
E Restriction between the low-pressure and high-pressure pump
F Faulty high-pressure pump
G Faulty high-pressure control valve
H Power/ground supply fault to high-pressure control valve
I Faulty high-pressure sensor
J Faulty wiring to the high-pressure sensor
K Faulty injector/s
L ECU power or grounds
M ECU software
N ECU hardware
One fault with 14 possible causes? There’s only one thing for it:
4: Testing, testing, testing - It’s all about priorities
There’s a straightforward reason why this vehicle hasn’t been diagnosed on the earlier visits. Quite simply, the right tests have not been completed at the right time. That’s all about to change.
You need to decide how best to test the possibilities. This is how I would prioritise:
A Fit fuel flow tester in low-pressure supply
B Scope CH1 WPS 500x pressure transducer pre-fuel filter
D Scope CH2 WPS 500x pressure transducer post-fuel filter
C Scope CH3 in tank pump 20Khz PWM positive supply from low pressure pump control module
D Scope CH4 ground in tank pump ground
E Scope CH5 in tank pump current
F Scope CH6 high-pressure rail sensor signal
G Scope CH7 high-pressure control valve +
H Scope CH8 high-pressure control valve –
The objective is to carry out as many tests as possible in unison. I’ll also be able to road test the vehicle and stand a VERY good chance of diagnosing this problem the first time the fault rears its head.
5: Diagnostic sniper
Diagnosis is all about ruling out what’s good. Do that methodically and the problem will reveal itself like an enormous arrow descending from the sky: “THE FAULT IS HERE.” This is exactly what will happen when you road test this Golf.
You’ve set up your tests and set off on your test drive, complete with assistant. You’ve been driving for around 10 minutes and just as Mr Brown predicted the vehicle loses power and you’re forced to pull over. This is great news. Let’s take a look at the clues:
With a focus on technical challenges and potential cost with diagnostic equipment and servicing, I think we should explore the technology that drives the need for specialist tools in both service and repair. I’m going to look at Euro 6 generation 2 diesel emission systems.
I’m convinced that the more technology manufacturers throw at improving diesel combustion, the more problems they introduce. As usual, my knowledge is based on Volkswagen-Audi Group design. Engine design innovation is now closely following that of gasoline direct injection, alike to that of the EN888.
MDB concept
The VAG MDB concept engine design is a world based modular system. This allows for a more flexible production with regional variation based on local emission standards. The three basic modules are the intake systems, a central engine core based on the EN288, and the exhaust or emission module.
The EN288 engine has 3-cylinder and 4-cylinder options with EU4/EU5/EU6 compliance. It is a cast iron block, alloy with the 3-cylinder variant, with and without balance shafts, crossflow alloy cylinder head with variable valve timing. A fully mapped and integrated coolant pump ensures maximum thermal efficiency.
It important to understand that there are significant differences between the 2.0/1.6/1.4 3-cylinder and 4-cylinder design concepts, so various comments across the range of options will not reflect every variant.
The 4-cylinder head has an offset valve layout. This introduces turbulence within the combustion chamber. The 3-cylinder valve layout is a conventional layout with swirl flaps in the intake module. Intake valve variation allows for a delay of intake valve closure (IVC) with a reduction of cylinder pressure during compression, reducing temperature and NOx. The control variator utilises oil pressure, with a backup accumulator to adjust IVO/IVC.
Emission control module
The emission control module is without doubt the most radical evolution. High pressure EGR is introduced via a valve directly from the exhaust manifold to the inlet, with the single aim of heating the 3way Euro 5 catalyst, or 4way Euro 6 catalyst when the engine is cold (see fig 1.)
Low pressure exhaust gas passes via the EGR cooler, catalyst and particulate filter into the exhaust system. During NOx reduction strategies, exhaust gas is re-circulated aided by the EGR control valve and exhaust venturi or brake as it is referred to. This device partially closes the downstream exhaust circuit increasing upstream exhaust gas pressure by 30-40mb. This helps self-cleaning of the cooler and allows for AdBlue to be injected post cat pre DPF. Mixing is aided by the turbo. This also provides for the wideband NOx sensor to monitor NOx content before it enters the catalyst and particulate filter.
The exhaust brake also increases the upstream exhaust gas volume through the cooler, aiding self-cleaning. In addition, the emission control module has the task of reducing ammonia NH3.
Fuel delivery pressures have increased to 2000bar with delivery phases from 3/5/6 events depending on the operating profile. Additional combustion monitoring is achieved via a pressure sensor built in a heater plug. The sensor data helps the PCM calculate fuel quantity, timing and EGR values.
There is also a feature I have supported for some time, relating to how the DPF is subject to regeneration or replacement based on saturation levels.
Catalytic reduction
4-way catalytic reduction, co, hc, NOx, nh3. is based on principles of absorption followed by reduction (see fig 2). This is assisted with noble metals; platinum, palladium, and rhodium. An additional ingredient, namely barium, is used to assist in NOx reduction. Barium also helps absorb sulphur requiring periodic de-sulphation. The PCM performs this process every 600mls by ensuring exhaust gas temperature around 600-650°C. This should take 15-20 minutes.
The location of the cat and SCR has required copper zeolite to assist with higher operating temperatures. The additive injector is water-cooled to help protest both the nozzle and electrical circuit. The exact control of injector timing and additive quantity is a precise value based on the specific vehicle ID. To test the 5bar delivery pressure and two-way control valve in the additive tank module requires OEM software. Additive delivered into a calibration flask must meet exacting min-max values.
We have also conducted tests on the variation in quality of adblue. I recommend either a SG test or refractometer ensuring 32.5% ratio of active agent and de-ionised water. We have seen large variations in agent quality. It should have little or no odour. Please note; a strong smell of ammonia should not be present.
Performance
I’m not insensitive to the improvements that diesel vehicles have attained. It’s just that they don’t perform as intended under actual road conditions. We find SCR additive consumption is often excessive requiring premature refill. Additive injector crystallisation and EGR cooler blockages are commonplace as well.
Be careful when interpreting DTCs suggesting a blocked DPF. It can often be the cooler that is blocked, restricting gas flow and affecting the algorithms for AMM, gas temperature, and DPF pressure. This will of course directly affect regeneration strategies.
Returning to my initial opening thoughts, is it clear that the fiscal life of a vehicle, especially diesels, could be ended by the cost of a single repair. The future will I believe move very quickly within certain demographics to PCPs and rental rather than ownership. This is just what the manufacturers want.
This means that in a shrinking market is even more vital to understand and invest in the latest evolutions.
I am a bit of an ‘old-skool’ mechanic, I enjoy working on vehicles that are mechanical and do not depend on computer wizardry to move. I regularly work on 1960s Porsches in all their air-cooled simplicity.
Just last week though, a friend asked if I could service their 2017 Audi Q5. We arranged a date and off I went to pick this car up. This is a hugely impressive vehicle with every piece of technology you could ever want. Confidently, I got it up on the lift and started checking it; brakes, suspension, exhaust. I also let the oil out. Everything was going accordingly to plan at this point.
I always make sure that when a car is still within its manufacturer warranty that I use genuine parts and oils, for me it protects the customer on any issues.
For a car that was only two years old everything was as it should be. Unfortunately, this is when the headache started. I screwed in the new sump plug and lowered the car ready to put the oil in, but wait, no dipstick! Manufacturers now don’t include a dipstick. Is it weight-saving gone mad or a great idea from someone who doesn’t work on cars? Following this unhappy discovery, I researched and found out the quantity it should have, put that in and then checked the on-board computer. What a palaver.
Next came the replacement fuel filter. The price of the thing was enough to put me off but I found the location, now at this point I had spoken to a friend who is more in tune with modern cars and stated that to replace the fuel filter you the needed to plug it in to a computer and prime it! The fuel filter replacement was then put on hold for another day when I could have the car back.
Next on my list was to reset the service light, this too needed specialist diagnostic equipment for Audi vehicles. It wasn’t going well, I could sense it was going to be one of those days.
Defeated by the technology of today, I decided to contact the owner and get the car back until I could call in a favour from a friend who had spent tens of thousands on diagnostic equipment.
The icing on the cake to my disastrous and unproductive day was the service record. I normally relish the challenge of getting my service stamp within the lines and making sure that it is readable. It is a skill that takes much practice to master. Imagine my horror while sifting through the car’s endless manuals only to discover that there is no service book. It turns out that it’s all online now. I’m not sure I’m ready to put my service stamp into retirement just yet.
Alas, the Audi will be returning to the workshop in the next couple of days. Sadly, I won’t need any tools to finish its service – just a computer.
As we move towards through summer, motorists are dropping the dial across the spectrum on their climate control systems.
According to Adam White, Workshop Solutions Director at Euro Car Parts, repairers can make the most of the opportunity if they are properly equipped: “The key to profitability is offering the right services and performing them efficiently, in terms of both time and cost. By those measures, air conditioning is one of the most profitable service areas a workshop can be involved in – given the right expertise and equipment. Unfortunately, air con work is sometimes overlooked by garages who fail to see the potential profits it could bring to their business. With summer here, there are lucrative opportunities for those who are prepared.
“Air con is a key growth area for UK garages. A lot of customers that visit a workshop have some form of issue with their air con system and the average job takes just five minutes. It’s easy to see why air conditioning remains one of the most profitable services that workshops can offer. If you want to make the most of the summer rush, now is the perfect time of year to invest in quality equipment.”
As many workshops will know, automotive air conditioning systems use one of two specific gas types; either R134A or 1234YF. Adam observed: “Perhaps the most important decision for a workshop is whether to use a dual gas or double single gas setup. This will likely be dictated by the size of the business or the amount of air con servicing undertaken. The primary advantage of a dual gas machine is that you only require one unit to cater for both R134A and 1234YF, meaning less occupied space and reduce costs. The alternative is two separate machines, one for each gas. Having two machines is more expensive but it allows you to service two vehicles at once and offers greater opportunity for revenue-generation.
“Workshops should ideally have the capability to cover both 1234yf and R134a systems. We aim to support the independent aftermarket in any way we can. Our latest Workshop Solutions brochure outlines the profitability of air con servicing and is well worth a read. New machines only require a hands-on time of around five minutes, with the total air-con service time taking between 45 minutes to an hour. This effectively gives you an additional pair of hands in the workshop – an hour of labour that can be used and charged elsewhere.”
Adam continued: “Autoclimate’s products cover most of the UK market and it offers a support service that can fix 72% of the issues workshops encounter over the phone, minimising downtime. For the remaining problems, the company has 18 dedicated air con repair specialists committed to performing on-site repairs within three working days. For peace-of-mind, all its air con machines are eligible for a five-year warranty package with included annual servicing.”
Adam concluded: “Whether you are considering investing in your workshop’s first air con machine or a seasoned veteran looking to upgrade, make sure that you evaluate the market to find one that best suits your requirements. The Workshop Solutions brochure is a great source of information and advice on how to maximise workshop profitability. The latest issue provides interesting insights into air-conditioning, including comparisons of popular models and useful finance examples.”
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