Year of Manufacture *: 2000->
I produce many instructions of my own for items outside the trade from producing a Power point presentation to working my Roxio digital picture – video procedures. Again in these complex days how easily we forget how to do all the bells & whistles especially with software and either a flow chart or a picture can tell a thousand words.
If we do put something like this together it needs to be standardized in a flow chart form or an A – B procedure to stop us from side tracking and confusing how to get to the basics as fast as possible, maybe someone could produce a flow chart that allows people to fill out their procedures?
I have produced many procedures from Diagnostics procedures to diagnosing a catalytic convertor to basic electrical checks to parasitic battery drains etc. etc. Some of my earlier attempts are rather wordy and try to cover too much detail, I’m sure some of you guys out there could pick holes in my procedures and my data, but wouldn’t it be good if we produced a best practise library which we could refine and refer some of these queries we get on UKAT before we start to attempt to diagnose other people’s problems, maybe we would all get there more quickly less frustrated, or we could repair cars more proficiently by sharing more helpful information. I’ve just contributed a Petrol misfire chart below which I expect my guys to follow. See what you think.
John Kennard.
Best Practice Procedures, Diagnosing Petrol.
Misfire Procedure: Ignition – Fuel – Compression – Vacuum - ECU
1. Check Ignition leads & determine cylinder misfire, COP Coil on Plug (Read fault codes), Check electrical connections, rotor, cap, king lead, ignition lead, COP rubber shaft & electrical connections, Check dampness or water in plug holes, spark plug note: colour of plug & ceramic for cracks or discolouration. Lastly Check COP output with tester & compare, then scope primary & secondary wave forms & check Kv’s
2. Check fuel injector electrical connections, noid light for injector signal if good, injector connected feel for pulse or stethoscope for ticking injector & compare a good cylinder injector, check feed voltages to injector. Check fuel rail pressure. Lastly scope injector pattern & voltages.
3. Check compressions & compare cylinders, Tight tappets? Hydraulic tappets over pumping? Cylinder leakage test & compare cylinders. Oil down bores & re-check compressions.
4. Check for vacuum leaks near cylinder in question, carry out smoke test, check vacuum pipes to MAP sensor and check PCV Valve. Has variable flaps broken in manifold & blocking intake?
5. Is ECU driving coils or injectors? Check data output feeds & earths & connections to ECU,
Lastly carry out battery reset.
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