95ZRagtop6M

When I turn the key on, the pump primes to about 48 psi and I get about 10-11v at the pump while the pump is on. When the car starts, the pressure drops from 42 to 0 because there is no voltage at the pump. If I use the jumper under the hood to power the pump, the car runs fine with normal fuel pressure.

Any ideas??? What controls power to the pump when the engine is running?

BTW: It's a 95 LT1 383 A4. LE3 heads and cam.

sleeperMULLET

iTrader: (4)

did you try switching relays? the pcm controls the coil side of the relay to send power to the pump. The internal contacts could be corroaded or worn. If you switch it and it still doesn't work, then check to see if the PCM is working the relay correctly. I don't have a wiring schematic so I couldn't tell you what wires to check.

95ZRagtop6M

Yes, the relay was the first thing I replaced. I'll do some more testing to make sure the relay is getting the signal. Thanks!

95ZRagtop6M

After doing some research on the forum, it sounds like the behavior is consistent with VATS problems. I'll check the program this morning to make sure its disabled.

95ZRagtop6M

Found the problem. The ECM wasn't responding to CATS, so I figured I would swap the ECM with another one I have. When the pulled the ECM, two connectors were off!!! I connected them and it fired right up. Minor details!!

I just bought the car and it was running on Sat, so I was stumped. All good now.