Hi,

To make things easier for my with my project i have brought a Audi V6 coupe from someone on another forum that had running issues.

I have been unable to start the car, it coughs when you first turn it over then nothing.

Have checked the immobiliser is disengaging and that the spark plugs are sparking and the HT leads are in the correct order.

The plugs are soaking wet and smell of petrol so there is fuel getting through and have replaced these plugs.

The car still won't start, I am not sure what it could be, i put fresh fuel in it but there is quite a bit of fuel in it when i got it which could be stale so I am tempted to see if it will start on easy start and then if it does start drain the tank. but if this doesn't work i am not sure what to do.

Anyone got any ideas what could be at fault? It could be the crankshaft sensor but i would expected no sparks if this was the case.

Cheers

if the plugs are that wet i suspect over fueling.
is it possible to disconnect cold start?
try drying everything out and removing fuel pump fuse,fire it up on easystart/brake cleaner etc

If it's the old K(E)-jetronic I would check the warm-up-regulator:

http://www.diagnostic-assistance.co.uk/mech_inj.htm

If it's a younger model. Check the fuel-pressure-regulator which is on the fuel-rail (simply suck on the vacuum-hose; on the righthand rear top of the engine)

[Edited on 23/2/09 by t.j.]

thats a good plan will disable the fuel pump and see if the car will run on easi start,

if it does will drain the fuel tank and try fresh fuel and see if that helps.

Not sure how the cold start mechanism works on this engine, I would thinks is a ecu controlled choke?

what about the engine-code and a nice picture of the engine-bay?

that would be a good idea, will take a pic tomorrow, and will get the engine code.

Is the 2.6 V6 that is in an audi M reg coupe just to let you know

I don't know what the M is....

I think it is the ABC-engine. Looks like a normal Motronic from Bosch. So it's not a mechnical injection.

There can't go to much wrong there.
So check for the ingredients.
- temp-sensor
- fuel-pressure (to high?)
- presure regulator (leaky tru vacuum-hose back of right cylinderbank)
- big vacuum leakage (hose to vacuum brake booster)

google...
electrics

M reg = registration year in the UK, so 1994/95 vintage..

right have tried to make it run using easystart and with the fuel pump relay removed. No joy, just coughed the once then nothing.

I am beginning to think the prob with this car is more serious. The ignition timing must be ok, so I am think that the cam timing is wrong. It can't be out by much as it turns over fine but i would think one notch out would mean it wont start.

Here is a pic of the engine bay, not been able to find an engine number though, its pretty dirty!



so if anyone has anything else i can try i would love to hear it.

Just wish my dads compression tester fitted!

The valves could have hit the pistons and got bent enough to let it turn over but with no compression, maybe the timing belt snapped and has been replaced or has simply jumped a few teeth, one notch out and it would still run.
Paul

quote:

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Originally posted by trogdor
right have tried to make it run using easystart and with the fuel pump relay removed. No joy, just coughed the once then nothing.

I am beginning to think the prob with this car is more serious. The ignition timing must be ok, so I am think that the cam timing is wrong. It can't be out by much as it turns over fine but i would think one notch out would mean it wont start.

Here is a pic of the engine bay, not been able to find an engine number though, its pretty dirty!



so if anyone has anything else i can try i would love to hear it.

Just wish my dads compression tester fitted!

---

Sometimes a compression tester isn't needed, if it has bent the valves then the engine just spins over when cranked. Sounds totally different to a healthy engine.

what kind of noise would it make if the valves were bent when it was turned?

that could be the case, i am gonna check the cam timing tomorrow.

No compression sounds like Whirrrrrr (really quite quick) almost like the starter spinning but not catching the flywheel.

well at least it doesn't sound like that, Presumably it would also turn over quicker too. It should be about 200rpm?

Will have to see if i can find a compression tester that will fit if the cam timing is fine.