Mike_k

Hey guys. I've got a 2007 A8 FSI that was throwing low fuel pressure codes for the low pressure side of the system and if you really pushed it it would sometimes throw low pressure codes for the high pressure side of the system as well. A buddy of mine that happens to be an Audi tech told me to swap the low pressure fuel pressure sensor as they often fail. Did that and no change. The code came back right away.

Perhaps by coincidence the car started stuttering really bad at anything over 50% throttle today so now I know I'm not dealing with a false signal. I'm dealing with legitimate low fuel pressure.

The problem I'm having is determining which low pressure pump is failing. On my old 2004 it was easy to determine which pump was failing as the driver's side pump only ran when needed and for 30 seconds at startup. It's not so easy on the FSI cars and I suspect both pumps are running at some degree all the time.

I'm wondering if someone here has a copy of the diagram for the fuel system on a 2007 - 2010 4.2 A8. I'm just trying to understand for my own purposes how the system works.

mishar

Are you sure that it is different than non FSI?

Mike_k

Nearly certain, yes. Nonetheless, it was one of the low pressure pumps failing… and the serpentine belt… and the oil separator… and my American Express card… :-)