12V Lift Pumps? Please Help
 

Ok, this is not my truck but is a friend / customer of mine that was going to stop by today to have me look at something else.

Anyway, he fired the 1996 up and it ran ok for about 100 feet. Than poof nothing, notta, zilch. He is now in the middle of the exit lane of the complex and he is 70 miles from my place at this time.

I don't have any 12V pumps in stock and I'm not sure if this is the problem but I ran through everthing I could think of over the phone and it doesn't want to start.

FYI:
There was a wire harness disconnected from the underside of what I think is the pump (description over the phone). Customer plugged it back in, there was a small amount of wet fuel around the area - small unidentified leak i guess.
The truck has power, the starter makes lots of noise but no fuel to the P Pump.

Ideas? Thoughts?
I may drive down and help the guy out but I'd like to know what I'm looking for first.

Thanks guys.:sos::argh:

The P-7100 is not the same animal as a VP-44. I believe the IP can draw enough fuel so that the truck will run (same as the VP-44 to an extent). To me it soulds like he has air in the system. But, its hard to tell what it is due to the fuel leak - could be the rubber fuel hoses letting air into the fuel system, could be a leak at the filter housing, could be the prefilter, could be the area around the fuel heater letting air in.

Checking the fuel pressure is pretty easy. You just drill and tap the banjo bolt on the P-7100 inlet and screw a guage on. (get a 1/8" pressure guage)

the wire has nothing to do with the P-7100 on a 96

I think yer got some air in the system too like Doc says

have him crack the injector lines on 1,3,4 then turn it over till he gets fuel weepin then tighten em down and start it up

He's got a pressure gauge - this was one of the reasons he was coming up today - the gauge was on the "fritz".

I've never seen a 12V LP go south but I'm sure they do like anything over time. Doing diagnostics over the phone is difficult.

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I had him crack lines already - no fuel. I'll get him to do it again. Stay tuned.

Thanks

D.

Yes they can die - but if you leave info out - it makes it that much harder. What does the guage say? if the guage is dead...get any cheap guage...home depot may even have them.

FWIW, it sounds airbound.

Devon......the lift pump on this truck is mechanical and drivven off a cam lobe

they very seldome fail but they can

Hence the reason why I'm baffled. Changed enough 24V pumps to know better.
This truck is a 96, full gauges, big sticks, BIG Twins, Big exhaust and so on. The truck is capable of 54+ pounds of boost.

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the truck is on a flatdeck going to the another shop to get fixed.
subject closed.