#desperatehelpneeded

[Damo66]

Hello guys 

I'm hoping there's a Joda on here that can help. Ive had my a4 avant 5 yrs now and it's never nmissed a beat until 6 months ago. It is a 3ltr Tdi v6 automatic. I was driving along then stopped in stationary traffic and at tickover just cut out dead, turned her over and it eventually started with a couple of pumps of pedal but I had never had to do that previously on start up. The second time this occurred  I was parked facing down a hill and it would not start. So left the car and sent a recovery friend to get it  at which point it started straight away. In to the garage it went and they could not find anything wrong with it and the historic codes they said were relating to injectors  so I'm thinking injector replacement or   Fuel backfeed somehow. They said run it till problem is constantly there. So 5 days of running it no problems it cuts out instantly whilst crawling in slow traffic again and again it will not startso we recovered it to my garage who said it's electrical it must be a relay so my electrician checked it all and said it was not electrical and it was fuel related and proved it by starting the car with easy start at which point it fired up virtually straight away. So the garage did injector leak off tests and all injectors were delivering equal amounts of fuel so the injectors have been ruled out as ok ? So then they found a fuel pressure sensor on the end of the common rail was not holding pressure so they changed it ( £300 ouch) I took it away drove it for 1/2 day and boom it cuts out again with exactly Same problem but on a busy roundabout causing mayhem luckily there was a garage very close by so I borrowed some brake cleaner and used it as easy start and she fired up straight away at which point I drove it back to the garage where it still is after a month!! And no further forward ! Any help would be greatly appreciated 

[Dan3222]

Not sure if this will help or not as I am relaying info from a completely different engine here. 

It sounds pretty much like fueling issues obviously. Symptoms sound very similar to T5 engines which have tandem fuel pumps. However, after a bit of reading and part sourcing it's clear that you engine does not have one. It has a belt driven high pressure fuel pump on the engine. I can't help but think this is failing somehow. The primary pump located in the fuel tank is obviously working because if it wasn't you would have cold start problems and hot start too. But the high pressure pump failing could well lead to cutting out. There is one second hand pump on eBay right now. From your car year too. Item number 352068683829, though it does say it's from an Allroad but I do think it's the same engine? Worth a phone call.

However. You could do with having some live data readings to see if it throws up a new code when it happens again. Crank sensor intermittent faults lead to cutting out too!?! But then your car does seem to start easily with a spray of juice like brake cleaner. Modern engines can sometimes be very confusing!! I miss the good old days of a bit of hose here and gaffer tape there to patch you up to get home!!

[PaulFurlong]

I am not joking, but i had the exact, i mean exact same symptoms on my S6. took it to my local garage they said it was a fuel problem but recommended that i take it to a VAG specialist.

i took it to my local VAG specialist and it had them completely stumped as they couldn't replicate the fault in the garage. after about a week of them having it and as a part was en route from Germany, mainly the fuel pump control module, they changed the low pressure fuel sensor at the rail as it was intermittent and i have not had an issue with it since.

i got the car back after a week, £120 cost inc labour, that was 3 weeks ago and not an issue since.

i know that they are two completely different engines, i have the V10 not the V8, but the symptoms are identical.

hope that sort of helps somewhat.

regards

Paul 

[Steve Q]

Welcome to the forum Damian :) 

sorry to hear your having issues. As you've seen the members on here are a friendly and helpful bunch :) 

cheers

steve

[Damo66]

Just an update guys, well i changed the fuel regulator on the end of the common rail and had no joy so I changed the fuel pressure sensor in the rail and still no joy then finally I have changed the fuel pressure regulator on the side of the high pressure fuel pump and bingo  we are back in business although interestingly having called Audi dealers and Tps they both said there is no regulator on the side of the pump so I have ended getting it from Bosch direct. I have a small problem now in that the regulator weeps so I'm hoping new orings will solve that, fingers crossed I'm back in the game again .

[Steve Q]

Glad you got to the bottom of it Damian! Isn't it funny how Audi have said the part doesn't exist there! I wonder if that part is designed to be changed at the same time as the pump if that makes sense? 

Cheers

steve