Fuel pump

JOEKIDD1

MEMBER
1990 PONTIAC FIREBIRD
3.1L
6 CYL
2WD
AUTOMATIC
230,000 MILES

A year or so ago, I had some work done on the ignition. The mechanic totally messed up the job. So the ignition never got fixed and the fuel pump wont shut off. Since then, the car is not starting due to the anti theft device. I have a professional working on it right now. But he has no idea how to fix the pump, which by the way is still good. I just need to tell him what to do and where to go with this thing.

Tuesday, February 21st, 2017 AT 1:34 PM

3 Replies

JDL

MECHANIC
16,098 POSTS

You maybe way ahead of me, but, other than the initial prime without rpm signal during cranking, the fuel pump relay will not energize. Now, there is an oil pressure switch in parallel with fuel pump relay, just a redundant power supply to the pump. If that switch is stuck in the closed position, the pump will run until it runs down the battery or burns up the pump.
Your mechanic does not have access to wiring diagrams for your vehicle?
Is this an after market security system? I do not appear to have anything on it?

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Tuesday, February 21st, 2017 AT 2:55 PM

JDL

MECHANIC
16,098 POSTS

Just to add, in the diagram, that fuse is hot all the time.

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Tuesday, February 21st, 2017 AT 2:57 PM

STEVE W.

MECHANIC
14,024 POSTS

1990 Firebird would have an early chip based VATS system. The most common issue with that is that the wires break at the ignition switch and it can't read the key.

For the pump, check that the fuel pump bypass wire (red wire, usually taped in the harness near the fuel pump relay) wasn't jumped to power to get it to stay on during the other shops attempts at repair.

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Friday, February 24th, 2017 AT 7:19 AM