Mechanics

99 4.3L FUEL PUMP

1999 GMC Jimmy • 6 cylinder 4WD Automatic • 170,000 miles

1999 gmc jimmy 4.3l. Just replaced the fuel pump and two days later the fuel pump stopped working. Pulled out the new fuel pump and replaced with a another new one. My question is what would cause the new fuel pump to go out? I know there is a possibility that it could have been just a bad fuel pump or I was wondering if there could be another kind of electrical problem that would cause the fuel pump to go out? Any suggestions?
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Darrenbrandt
April 24, 2011.




Check and test the fuel pump fuse, fuel pump relay and the fuel pump and oil pressure sending unit-also test for voltage drop problem

Rasmataz
Apr 24, 2011.
They have a known problem with the contacts in the plug at the tank.

Wrenchtech
Apr 24, 2011.
I did just find that the oil sending unit was unplugged. How would the oil pressure sending unit affect the fuel pump? How can I tell if the fuel pump relay is bad?

Tiny
Darrenbrandt
Apr 25, 2011.
The oil pressure sender is a redundant power supply to the fuel pump. The truck can run with either/or working properly but if it loses both, it will not run so there is a good chance you have a problem with the relay. When running on the oil pressure switch only, you will have a long crank before starting because you aren't getting the 2 second prime supplied by the relay.
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Wrenchtech
Apr 25, 2011.

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