Our AAN engines have
electronic fuel injection. The pressure for the injectors comes from a totally immersed rotary vane electric fuel pump that lives in the fuel tank.
Here is more information about the
J17 fuel pump relay and its importance.
Fuel pump, PN 8A0906091G, is item 39 in this diagram:
This 091G fuel pump is available as a VDO/Siemens or Bosch as OEM or Pierburg as aftermarket. These pumps are fine for stock, and MTM Stage 1+ levels but above that, e.g. RS2 and beyond, they run out of ability to provide the required fuel flow at 86 psi (4 Bar (58 psi) plus 28 psi boost). At that point a Bosch Motorsport 005 or 044 is likely required to prevent fuel starvation and massive pinging.
The
AAN Engine Manual says this about testing the fuel pump:
Access to the fuel pump is through an access plate on the hump in the trunk (sedan) (or just behind the back seat in an Avant). Pull the carpet up and you will see this round black metal plate:
Once you remove the three Phillips head screws, you will see something like this (minus those two red connectors I was using to test the voltage at the pump during the
fuel pump relay DIY development):
A detailed procedure to test and/or replace the OE fuel pump is found
HERE