Audi A4 V6 2.5 tdi starting prob's

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Wed 14 Jun 2006 07:13
Audi A4 V6 2.5 tdi starting prob's - mark25
All,

A colleage is having a problem with his Audi TDi, it won't start the day after a hot day. If the temp's above 30 deg the car won't start the next day, it turns over at the normal speed, but just doesn't fire. This symptom started last summer when it happened a couple of times. On each occasion the car is towed the the Audi dealer where it starts and runs perfectly, with no fault codes logged. It's just done the whole winter without missing a beat, but just started playing up again with the recent hot weather.

Any ideas?
TIA Mark

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Wed 14 Jun 2006 10:16
Audi A4 V6 2.5 tdi starting prob's - Hamsafar
I have read that there is a fuel cut off valve in the fuel pump on the engine and it has an o ring on it which can come adrift or cause it to stick. I think it's on the pump and looks like the type of temp sensor you get in a radiator (big hex bolt with electrical connector) It's a common problem.

The other may be the anti-shudder valve which is an intake shutoff valve which stops run-on shudder when you switch the engine off. This could be sticking.
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Sat 17 Jun 2006 07:17
Audi A4 V6 2.5 tdi starting prob's - mark25
Thanks for the info.

It was still not running at the garage this time, so Audi have just replaced the pump because they couldn't hear it running. The car then ran but there was 2v across the fuel pump relay contact with the new pump running, so that's been changed too. It sounds like it was a combination of factors, and a shame they didn't try the relay first. If it happens again i will check the above and the fuel lines at the fuel filter for leaks, which seems to be a re-occouring theme.

Mark
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