A6 V6 engine problem

[willholmania]

Sorry about the non S2 post but my mate has a 1995 Audi A6 quatro 2.7 V6 that’s playing up. If you crank it it fires up but the rev counter’s stopped working. The red light with a picture of an oil can on it flashes then the engine dies after about two minutes of running. It will then restart and the process repeats itself. There’s water in the nearside rear footwell and the RAC bloke reckons the problem is related to water getting into the electronics but his diagnostic gear wouldn’t work on a car this old.
Any ideas?

[sheppardnias]

If the 2.8 V6 is anything like the S6 the ECU will be in the front passenger footwell under a plastic shield. Water ingress is always possible but may well not be the problem.

First thing that needs to be done is find out why the oil light is on.. Has the oil pressure sensor gone faulty, is the wiring damaged etc. You did not mention if the car has an oil pressure gauge or not. The S6 doesn't so I'd guess the same is true for a 2.8. If this is the case you need to get your hands on an oil pressure gauge and test the engine out. If the oil pressure is low enough to leave the light on, you could be in for a big bill and it could be the reason the car shuts off. I don't know the Audi ECU well enough to say but I do know of of cars that switch of with low oil pressure.

I haven't had a 2.8 but I can say that my 2.6 coupe ran 5 Bar oil pressure when cold and 2.5 Bar at full oil temp. Both pressures are at tickover.

I saw low oil pressure on the V6's when I was buying the Coupe and every one was on an engine that smelt bad. You could smell the oil with the cap off and not only was it discoloured but had the smell of fumes passing rings etc.

If the engine has low oil pressure be carefull how far you go with checks. Parts are expensive for the V6 engines and you could well end up throwing good money at junk.

[willholmania]

I'm not even sure that the light I refer to is an oil pressure warning light. My mate seems to think it might be a service light.

[sheppardnias]

Sorry but it is not a service indicator. The A6 has OL1 and OL2 that appear in the odometer. No sane manufacturer would use an oil can for service indication, how would you then show problems with oil pressure? Service indicators are words or spanners in my experience.

Check oil level, oil condition and oil pressure. If that's all good then start working into electrical problems.

RAC man should be able to get diagnostics from the car, it will have a black connector and a white connector in the main fusebox that will hook into VagCom. He just needs the right diagnostic equipment which is cheaply and freely available. That said, I wouldn't waste my time on diagnostics until you know that there is oil pressure. Audi engines are tough and last forever BUT only if you keep them serviced and filled with quality fluids..

[willholmania]

Okay - thanks. I'll tell him what you've advised.