fuses and relays for fuel system?

Summajet · Dec 4, 2019

I am preparing to crank motor and build oil pressure after rebuilding it. Besides the F/pmp relay what other fuses or relays would I remove from the fuse boxes?
The F/PMP relay is under the hood in the black box.
I do see a PCM B located beside the fuel pump relay F/PMP.
ARe those the only two I remove to keep fuel from entering the system allowing me to crank motor and build oil pressure??

Fless · Dec 4, 2019

Others will weigh in, but if you pull the fuel pump relay, then release any residual pressure using the schrader valve that is on the passenger side fuel rail under the engine cover (cover with a rag in case...), no fuel is going to be pumped.

Doubeleive · Dec 4, 2019

you can just pull the fuse, release the pressure as noted above on the rail or disconnect the fuel filter depending on the year, you can also pull the coil plugs off if you are worried about it firing up

Summajet · Dec 7, 2019

I have finally got motor rebuilt and installed. Everything is put back as it was before removal. The fuel pump runs even with no key in the ignition. I did replace the old oil pressure sending unit with a oem gm oil pressure sending unit. Had read that an opsu can cause fuel pump relay to keep running as it thinks it has oil pressure. Any ideas why fuel pump would keep running with no key??
If I remove the fuel pump relay, the fuel pump stops running. Also I cannot get the truck to start. It will crank over but not firing up.
Am getting gas on the fuel rails.
Thanks

Doubeleive · Dec 7, 2019

Summajet said:
I have finally got motor rebuilt and installed. Everything is put back as it was before removal. The fuel pump runs even with no key in the ignition. I did replace the old oil pressure sending unit with a oem gm oil pressure sending unit. Had read that an opsu can cause fuel pump relay to keep running as it thinks it has oil pressure. Any ideas why fuel pump would keep running with no key??
If I remove the fuel pump relay, the fuel pump stops running. Also I cannot get the truck to start. It will crank over but not firing up.
Am getting gas on the fuel rails.
Thanks

regardless of the fuel pump running while key off, fuel+spark+air is what it needs to run, you have fuel, do you have spark?

Summajet · Dec 7, 2019

I am going to check spark tomorrow.

Summajet · Dec 14, 2019

It was the crank sensor. I had a ac delco. I used a bwd today and it fired right up. I forgot they mention to replace the sensor connector also.

fuses and relays for fuel system?

Summajet

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Fless

Doubeleive

Wes

Summajet

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Doubeleive

Wes

Summajet

Full Access Member

Summajet

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