1999 GMC Jimmy Repair Question
Topics covered: Fuel pump, Oil pressure, Fuel pump relay.
Mileage: 170,000 miles.
Mileage: 170,000 miles.
Asked on April 24, 2011
99 gmc jimmy 4.3l fuel pump
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??
Asked by darrenbrandtAnswer
Replied on 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
Replied on April 24, 2011
They have a known problem with the contacts in the plug at the tank.
Replied on April 25, 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?
Replied on April 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.