Fuel pump help

[Tom Leppke-Hennig]

Michael said:

Hi everyone. Recently my girlfriend's 1995 90 Quattro died on the
highway and today I did some troubleshooting. There's spark, so I moved
to the fuel system. I jumped the fuel pump relay and it didn't make any
difference, so I then moved to the fuel pump. It wasn't making any
noise so I took off the cover in the trunk and got to work with the
multimeter; it's getting power but the pump isn't doing anything. This
leads me to believe the pump is dead.

One funny thing happened, though. When testing things today twice the
car started, ran for about 10 seconds and then died again. Both times
it sounded like there was activity at the pump but then it quit. Does
this change anything?

Anyway, assuming my diagnosis is correct, is replacing the pump
something I should tackle myself? Any advice/help/write-ups/etc. people
have to share would be much appreciated.

Thanks,
Mike

Mike, this is very consistant with the way fuel pumps fail. Your stages of diagnostics are
sound. I (and many others I am sure) have dissected fuel injection fuel pumps after they
fail like this, and it becomes clear why they act like they do once you have all the parts
in your hand. These are positive displacement roller pumps, and once the fine bearing like
finish has been compromised or worn through on these rollers and their mating surfaces, the
rollers are prone to jamming in place. The next time it is powered, it might rotate... and
it might not. Replacey the pump, drivey the car.

Tom LH
1995 90q