help!! audi a6 allroad wouldn't start yesterday, recovery came out, bled air out of the injectors and it started and ran fine.

However today it's doing the same thing. How can I go about diagnosing where the air leak is coming from??

the diesel pump system is under a high amount of pressure. You would certainly be spraying fuel everywhere if you had a leak- perhaps your fuel pump itself is going out?

Vag Com is your friend..the 2.5TDI is not in the US so I do not have any experience with it. But with the 1.9 TDI, there is a procedure to check fuel pump timing. If the 2.5l is similar, check this using Vag Com.

Another component to check is the MAF. IF your TDI drives like you are towing a 5000 kilo trailer, then you are most likely looking at a MAF.

my guess lift (or priming) pump.

i have a same problem with my car. don't know for sure what causes this, but when i leave my car with nose up some hill over night,all the fuel goes back in the tank and i have to bleed the whole system to be able to start it. but when i leave it with nose down the hill, it starts normal. so i am starting to think that the fuel filter is bad.
did you solved your problem??? and if yes please tell me how? cause i am runing out of hills to park :D :D :D

oh and mine is not a quattro so it doesn't have a fuel pump in the tank...