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Hi
I am the new owner of an RS6 AVANT MTM conversion, having been a BMW owner for years this is my first Audi.I have owned the car for 3 weeks and it has developed a weird problem which I would appreciate some help with.
Car starts and runs fine from cold but if I stop and engine is at normal running temp, it will not restart.
I checked for voltage at fuel pump at this juncture and found none
Car would then restart at around 65-75oC
I had it tested and a fault was indicated on the fan which I do not believe operated since I bought the car
I changed the coolant Temperature switch at the back of the engine and the fan now works but the temperature problem with the fuel pump still exists annoyingly
does this temperature switch feed into the Fuel pump drive module also......
Is the fuel pump drive module goosed !
Has anybody got any ideas as it is a right royal pain sitting around waiting for the engine to cool before starting
Thank You

Faulty Crankshaft sensor.

+1

Hi
The crankshaft sensor controls the injectors (timing) not the power to the fuel pump surely ?

Which fuel pump did you test? And at what moment did you test it / them?

The ECU controls the fuel pump module which controls the fuel pumps. If the crank position sensor is faulty the ECU won't attempt to start the engine. So it may not power the fuel pumps. If the engine is not cranking or not running then there won't be any power at the fuel pumps anyway.

Could be faulty fuel pump relay, too.

Or X-relief relay.

Given the low (relatively) cost, I'd change both.

Hi
1. Tested the voltage to fuel pump in the tank whilst cranking the engine when hot...no voltage indicated
2. When engine is at 65 oC it powers up and car starts
Where exactly on the car is the fuel pump relay and other part you mentioned....might just change the crankshaft sensor at the same time
Many Thanks

Also if the crank sensor was faulty it would have an adverse effect on the car when it was running, but mine runs fine when running.
This all seems temperature related as mentioned origionally

have you run Vagcom ?

The ECU controls lots of things from information it gets from loads of sensors. If One sensor fails the ECU will cause other things to happen , or not happen as the case may be

Hi
Havent run a Vagcom yet, cant get the car to one ...wont start now even when the fuel pump runs on initial trying to start !!!!
Getting pissed as the machine cost me a fortune and it wont run

Can't get your car to Vagcom? Where are you? Someone might be able to help you out.

Helensburgh scotland

Just been on another site AUDIZINE and I must say the guys on there are really helpful
Think I got the answer to my problem...will post result soon

Well don't leave us in limbo ! what have they suggested to you to fix it ?

Real shame we don't have any helpful people on here
Lets hope you get it sorted and don't have to come back on here.