3.0tdi Problems with the fuel transfer pump.

[Andjo]

Hi all. I recently ran into some issues regarding my 3.0tdi. Car turned off by it self, and wouldnt turn on again. I managed to get it started and read fault codes, which to my surprise, there was low fuel rail pressure. The car ran fine for about 2 days, and then did the same again, this time i just couldnt get it to start for about 2 days. I checked fuses and relays, ran a scan for fault codes, and none of it came out with any faults. I then managed to get the car started once again, and let it idle for about 4 hours outside my garage. Since i couldnt find any issues, i decided to take the car for a spin, and it died on me on the highway. Issue is, when it dies, it cuts the fuel supply, which i managed to track down to 1 thing. Whenever it fails, the ECU refuses to send a signal to start the in tank transfer pump. I checked all fuses, relays, pressure sensor, HPFP and so on, i even measured the outputs on the wires. If i manually activate the transfer pump with the OBD tester, the pump runs completely fine, no issues at all, pumps out the right amount of fuel, runs till i stop it again. I went as far as checking water temperature sensor, which i read could be the culprit(very unlikely i know), tested the crank postion sensor, cam position sensor, fuel relieve valve, high pressure fuel regulater, and wiring for all the sensors aswell. I checked all ground points, both below the car, in the drivers side near the footwell, in the engine bay, in the trunk. Battery is good, voltage is good, no fuel pipes are leaking or sucking air. WHat do i have left to check? Something tells the ECU not to activate the pump, and the thing that does that is intermittent. HELP

[hahnmgh63]

I'd try the Q7 section as there are more 3.0 TDI owners there than any other model so more of a knowledge base.

[Andjo]

Might be worth a shot, cheers

[papadelogan]

This forum is mostly US based and the only TDI's we got here are\were the Q7 and A7 in recent years. I'd also suggest checking out A5OC.com since that is Europe-based (UK\England I believe) and the TDI is more prevalent there.

[ICU2]

This forum is mostly US based and the only TDI's we got here are\were the Q7 and A7 in recent years. I'd also suggest checking out A5OC.com since that is Europe-based (UK\England I believe) and the TDI is more prevalent there.

Andjo, I Agree w/ the above, & as much as I find AZ useful/helpful, there is precious little info on/about TDI platforms across the Audi lineups stateside. I just recently purchased a 2014 A8L TDI & found most of my info on “AudiWorld”. FAR more info on TDI in general, along w/a more international flavor & input from across the pond.
If you haven’t sent an e-mail to them, you may try sending “DarkSideDevelopments” an e-mail. They are a UK based garage/service center & diesel performance shop. They may be of some help. Good luck from a fellow Audi enthusiast!