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View Full Version : lift pump reads 9volts?



DrumFunKen
11-01-2007, 20:33
Oil pressure sending unit??????

Basically the truck shut off yesterday just after start up. I noticed some fuel leaking out the back so we traced it to the fuel filter. Took filter out and it was trashed(just bought the truck 2 weeks ago). Replaced filter. Learned how to prime buy jumping the wires on the oil pressure sending unit plug to supply 12 volts to the lift pump. Truck started no problem. Did a few more tests to figure out why it shut down in the first place and found that the lift pump is only getting 9volts. Is that correct or should it be seeing a constant 12 volt signal?

will be replacing the sending unit tomorrow to see if that makes a difference.

More Power
11-01-2007, 22:42
Oil pressure sending unit??????

That'd be my guess... unless your batteries are only putting out 9 volts...

Jim

gmctd
11-05-2007, 10:29
Good one, Jim :D

Would really be helpful to know specifics on your truck, Ken - the '94-'95 trucks are OPS driven - the 96-up trucks are PCM driven, with the OPS as redundant augmentation - first case OPS is usual fix - second case, not - either case could also be wiring and connections: dirty, oxidation\corrosion, frayed wiring, etc.

And BTW - welcome to the 'Page....................