Process not problem

Part one

By Frank Massey |

Published:  06 April, 2022

With the first blossoms of the spring almost upon us, Frank thinks a fresh look at the importance of diagnostic approach is in order

First question: Is the journey strictly necessary at this time? Mistakes often start here, driven by pride and a stubborn determination to fix all faults. We are not here to prove our knowledge to all comers; We are here to offer a professional and profitable service. Faults not worth repairing fall into several categories:

A: Cost over residual vehicle value, which strictly speaking, is not our decision. However, I for one have found myself in the position of having successfully completing an agreed repair facing an ungrateful owner with the sobering reality of paying the bill.
B: A realistic success ratio. You are thinking of starting a journey without considering all the possible failure points; Where are you going? What is the time of day? Is there the potential for traffic disruption?  How long will it take? Intermittent faults may be so erratic in nature that there may not be enough opportunity to observe critical data to establish cause. Never forget the first rule of diagnostics; Fix the cause, do not chase the symptoms. Do you have sufficient uninterrupted time to apply? Will a badly scheduled workload disrupt your concentration?

C: Choosing your route. Typing the destination into sat nav is fraught with all the same potential errors of simply following scan tool messages. Firstly, the software assumes many decisions without the benefit of actual knowledge. So, what do we really need before setting off in our leap of faith? Put simply, we must possess more knowledge of our route than the tools on which we rely. My sat nav offers three route options, and I have to choose the one which presents the best chance of success. In order to determine this, I have to have detailed knowledge of the actual geography, road conditions, traffic density, and a plausible escape route should conditions deteriorate mid-route. I use two live traffic update systems to minimise error and often still lose time on my journey. In a similar way, we should, where necessary and possible, rely on multiple diagnostic options. Its imperative we have detailed knowledge of the systems we are interrogating, not limited to the simple physical components, but rather how the strategy ensures correct control and response. If you lack key knowledge, then obtain and study the manufacturer’s TPs. Similarly,  I always carry a detailed full UK map book. That is unlikely to let me down when I least expect it.

D: Hazards on the journey: Impossible to predict but often avoided by caution and observation, speed camera sites and a clean pair of eyes work the same as a responsive change in direction. Keep the customer in the loop with regular updates, photographs, good and bad news. Always remember the customer owns the problem and cost, you own the solution.

Incredible
Rhetoric over, now let us apply it to an actual problem, to see if it works. A Volkswagen Golf R 2.0 TFSI, fitted with the incredible 300 BHP 888 engine. The weather forecast did not bode well for our journey, i.e. serial faults included:

  •  Crankshaft/camshaft position error
  •  Map sensor specified/actual value deviation error
  •  Misfire per 1,000 RPM


Our first consideration before setting off: How? Why? When? Planning the journey, ask these questions. How did the fault occur in the first instance? More importantly, why? Recall my previous comments here, symptoms and cause. Finally, when did it occur, this may have an influence on extended damage. The route, with so many potential options. Where we should begin? The engine ran, so let’s keep it that way as long as possible. Study the map in detail. Fortunately, I know this area, sorry, power plant very well. having worked on several, as well as owning a SEAT Cupra.

Remember diagnostic tools are like route options, you have a choice. This is a sophisticated power train. Let’s conduct a quick recap, before part two exploring the method, and of more, interest my evaluation of our chosen test results.
    
A potential mechanical valve timing error? The engine has variable timing control on both cams, variable lift on the exhaust cam, mapped variable volume oil supply pump, dual fuel injection, direct injection on higher load, with port injection for the remaining speed load range.
    
Our chosen tools include the following: Serial data evaluation; Engine mechanical assessment with in-cylinder pressure differential evaluation; ASNU injector test for fuel delivery assessment. This means there is lots to cover with some interesting test data for me to present.

I am looking to find the shortest distance and fastest journey, with no traffic hold ups, and no speed camera faux pas.

Come back next issue to find out how I do.

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