1994 Suburban 1500, 8 volts at fuel pump

[88monteSS]

They tend to dislike being undervolted like that, so that may have contributed to it. Or it might've just been a bad pump, wouldn't be the first time that's happened. Personally I'd play dumb about the wiring & try to get it replaced under warranty.

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[ryanguy426]

RockAuto is replacing it under Delphi's warranty luckily. I appreciated the help figuring this out hopefully I won't have to update this thread about the second pump....

 

[88monteSS]

I ended up upgrading both of my trucks with racetronix hotwire kits when replacing the pumps & tanks to avoid this. They don't make a direct fit, but I got one for another application (I'm thinking it was a gnx, but I'd have to look for the invoice) with the same pinout & same shape plug, I just removed the plastic key so it would plug into my pump & harness.

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[Ehall8702]

I'm back again with my never ending Suburban project

1994 Suburban 1500, 350 TBI. I put in a new Delphi fuel pump, and the truck ran great, started easily and consistently. The truck sat for 2 weeks, it's now a no start, and only 8-8.5 volts at the fuel pump connector. Code 54. Can't hear the pump running whatsoever even with an ear to the tank.

Any diagnostic tips? I already swapped the pump relay with the one on my Sierra, same result. Put 12v to the gray wire out of the relay, nothing. Jumped pin G on the ALDL connector with 12v, nothing. Cranking until the oil pressure hits 40, and nothing.

Runs fine if putting gas or starting fluid down the TBI.
My instinct is telling me to throw another pump at it, but the 8 volts at the connector tells me it's somewhere on the truck and not the pump. Curious if there might be something common I'm overlooking maybe? There's nothing obvious.

Like 88monteSs said...I've seen 12v on a wire till u out load on it, finally found in one spot there was only a few strands connected