The fuel pump does not run. Less than 7 volts to fuel pump?

CUNNINGHAM587

MEMBER
11 POSTS

It is the original pump. The battery voltage was roughly 12.5 v at the time I jumped from #87 to pump. The voltage at the pump end of the wire was 11.65v. Maybe I have tunnel vision at this point, but should it not be the same as battery voltage?

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Wednesday, January 20th, 2021 AT 10:11 AM

KASEKENNY

MECHANIC
18,907 POSTS

Theoretically, yes you should but 11.65 volts is more then enough to run this pump to provide proper pressure. If you are concerned about it, jump to the pump again straight from the battery with a jumper wire that measures a half ohm or less of resistance (to know you are not losing voltage in the wiring) and then check the fuel pressure.

I bet it is low and at this point then pump is probably the issue. Clearly a restriction in the supply line could be there but that is unlikely in this case.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

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Wednesday, January 20th, 2021 AT 10:11 AM

CUNNINGHAM587

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Okay. For what it’s worth I did check the resistance in my jumper from 87 to pump before attempting to start. It was measured at.2 ohms. I can try a 12v source straight to the pump. I didn’t try that since I kept seeing lower voltages. Thanks again. Hope you and your family are doing well.

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Wednesday, January 20th, 2021 AT 10:11 AM

KASEKENNY

MECHANIC
18,907 POSTS

Okay. Clearly that is a good wire. I bet running off the battery will result the same no start which means when we check pressure and it is low then the pump is most likely the issue.

Stay safe. We are hopefully on the back side of this whole thing.

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Wednesday, January 20th, 2021 AT 10:11 AM