1992 Audi 100 Fuel Pump

Hi guys �here�s the problem with my son�s 1992 Audi 100 CS 2.8L Front-wheel-drive, 5 speed: It won�t start and run.

I replaced the fuel pump because no fuel was getting to the filter or fuel rails. (The spark was OK and the engine would fire if fuel was introduced directly into cylinders.)

But the new fuel pump wouldn�t charge the filter or rails either. So I tried the following diagnosticsâ� ¦

Fuse is OK. The fuel pump relay clicks when key is turned on. Relay should be OK too, then?

When ignition switch is turned on, without starting engine, test light will light (brightly!) For a second and go out when I hooked up leads to pump. This is correct, I think.

Another on-line mechanic told me it was OK to hook up pump directly to power to check if pump is running. (The pump is protected by 20 amp fuse so direct hook-up should be OK?) I did this and I can hear the pump humming and it did charge the filter once and the car ran a second after I started it.

However, now the pump just hums when connected directly to power and nothing comes out, even at the tank.

Any suggestions for how I can get the fuel system working again?

Thanks a bunch!

Steve