Please help
1997 Pontiac Grand Prix GTP 3.8L supercharged
New fuel pump; changed computer, changed fuel filter, changed fuel pump relay
Symptoms:
Scenario 1:
Key on – fuel pump starts for 2 sec. –pressures rack to 52 lbs-then shuts off (normal)
Car starts – computer says “fuel pump on” (normal)
Fuel pump has no power going to it- fuel pressure falls off-car dies
As soon as car dies the fuel pump pressures up and shuts off.
This cycle repeats.
At first after the car would cool down- it would run for a while before stalling
Scenario 2:
Car starts – accelerator is held to the floor
Rev limiter stalls engine at 4000 rpm
Engine slows to about 3000 rpm
Then speeds up to 4000 and stalls
This cycle takes less that 1 sec.- repeats until-
Gas pedal is released, then engine slows down and dies
Fuel pump starts pumps for 2 sec and shuts off
Manual says after the initial 2 sec pump to charge system – the computer waits (while cranking) to receive a “signal” (from where it doesn’t say) to send the “on voltage” to the pump relay. In another place says comp. sends a signal to another before the actual pump relay.
