The fuel pump on my 89 still runs forever after the car shuts off. I unplugged the F/P relay and it still runs. I unplugged all the underhood relays and nothing. There is a hissing sound coming from around the fuel rails and intake base. It even started to turn on when the car has already been off for awhile. All by it's self. Please tell me what could cause this.

------------------
89 FORMULA WS6 5.7
Aero Package
Dark Purple Hardtop!
Ram Air II Hood
Z28 Hi-Rise Spoiler
Hypertech Thermomaster
10-BOLT POSI, 3.23 GEARS
700-R4 Automatic
Modified Transmissions
K&N Filter Charger
Modified Mass Air Sensor
Ported & Polished Intake
Accel 8.8 wires and coil
Emissions Delete
Dynomax Exhaust w/Tips
McEwen White Faced Guages
Custom Sound System
(====] [====)
Power buldge hood
^^ FOR SALE ^^

 

most likley the fuel pump is grounded out since all the relay does is ground it while priming and while running if the relay was disconnected the ground is in the harness between the tank and the relay

 

Your oil pressure switch could be grounded and causing the fuel pump to run on.. Sounds crazy, but disconnect it and see what happens.

 

I should say on some cars, the oil pressure switch is a backup to run the fuel pump if the relays go bad, it wont keep you stranded. I had this happen to a couple cars i worked on in the past, and the oil pressure switch is to blame.. Pretty wierd actually

 

I replaced the relay yesterday when it started. I had an extra one around. That did not help. I will check out the pressure switch though. Is it the sender or the sensor one?

 

The one down by the oil filter (switch).

------------------
Matt

1987 GTA L98 MD8 GW6

"Stop Lights timed for 35Mph are also timed for 70Mph"