No start

2001 GMC JIMMY
279,000 MILES • 4.3L • 6 CYL • 2WD • AUTOMATIC
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TANYA WATSON
  • MEMBER
  • 2 POSTS
Husband recently changed head gaskets. It started and ran before, now when we turn key it will not start. It has power to lights, A/C, radio, etc. Fuel pump does not prime either. Can start it briefly after adding fuel to throttle body and jumping starter. And it will crank with tester touching 10 amp fuse. What could be causing this problem?
Mar 9, 2021 at 8:37 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 110,190 POSTS
Hi,

I'm not sure I understand. What fuse is he touching with the tester? Also, what kind of tester? Is it a test light, voltmeter?

As far as no fuel pump, have fuses and the fuel pump relay been checked? If you look at the pic below (pic 1), it shows the fuel pump relay in the schematic. First, confirm the ECM B fuse is good. Conform power to and from it. If it is good, check the relay.

If the relay and fuse are good, jump pins c2 and c3 (@ relay) to confirm the pump turns on.

Here are a couple of links you may find helpful:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

https://www.2carpros.com/articles/how-to-check-a-car-fuse

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The remaining pics are the entire wiring schematic for engine controls. You can use these as a reference.

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I hope this helps. Let me know what you find or if you have other questions.

Take care and God Bless,

Joe

Mar 9, 2021 at 7:07 PM
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TANYA WATSON
  • MEMBER
  • 2 POSTS
The relays and fuses were all good.
Mar 10, 2021 at 10:17 AM
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 110,190 POSTS
Okay. Did you try jumping the pins I mentioned to see if the pump would run? If there is power at the relay and it is good, power should go to the pump. If that is happening and the pump doesn't turn on, then either there is an open in the wiring (broken wire) or the pump is bad.

Let me know.
Joe
Mar 10, 2021 at 4:42 PM