p-pump no start-electrical

N

Nich00

New member
2000 p-pump..truck has only 120k on it and i did this swap back in 2015. truck has always been reliable and no issues. in early 2018, i parked the truck. i got the tuck out this past may, the plunger was not pullling up when I hit the key so I bought a new plunger and it ran fine.In August I moved the tuck into the shop to do a little work on it and went to restart truck, would not start. The plunger would stick up by hand, so i replaced fuses and that did not help. I checked the wires to the fuse panel, all looked good and frankly gave up...came back out about two weeks later and it fired right up...no more issues...this past monday night, i used the truck for about an hour and parked it. Now, no start again. I checked the fuses, good, but when the key is off, i have power to the plunger, when the key is on or cranking, no power to the plunger according to the test light.....im at a loss here....any ideas?
 
the way this was wired is coming off the plunger, ground, battery, and a wire to the key on the fuse panel.....what solenoid should i look for....
 
just checked the new plunger and its not sticking in the up position even by hand now...so i need a new one for sure there...
 
The 2nd Gen 12-valve wiring runs 12V to a relay on the firewall to pull the lever up. The relay is triggered off the brown wire that runs to the starter that triggers the starter solenoid. I don’t know about your conversion, but there should be a relay powering the solenoid.
 
so its a larry b harness and im going ahead and getting a new solenoid..yesterday it would pull up and stay by hand, tonight it will not..im thinking i have a bad wire somewhere..I heard a pop when i turned the key on ...after the pop, solenoid no work..
 
There’s your relay. You can get one at O’Reilly’s. Part #25-0102.

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odieub said:
The hold function does not run through the relay. Just the pull.
Click to expand...

Correct. He said he’d been having to pull it up by hand. There’s also a relay in the PDC for the hold up on the 12-valves. Don’t know what he’s got on his conversion. Just throwing out ideas for him. From his first post it sounds to me he has something wired wrong.

when the key is off, i have power to the plunger, when the key is on or cranking, no power to the plunger according to the test light.
Click to expand...
 
update...so im clear..i drove this truck daily for a year with no issues before i put it up. this has just started after i pulled it out to clean it up. the 12v power is running to the radio fuse which is where i found a lose wire. I got a new solenoid and out of the box, it will not stick in place by hand. when the key is off there is power to the solenoid but none once the key is on but the radio is on...i have no idea at this point..
 
coming out of my solenoid is three wires, one to the radio fuse for the power, one ground and one that is spliced into the what im assuming is the starter relay that is bolted right off the fuse box on the driver side fender...ill try to get pics so i can show you all..
 
When I did a P pumper into a 1st gen, I grounded the solenoid, ran the start side of the solenoid to the starter solenoid wire and the hold side to the VE pump's switched power.
Never had a single problem with it.

Mark.
 
Bottom line, none of your wires should be hot with the key off. Something is wired wrong. Which wire is hot key off?

Did you find the relay?

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i decided to rewire it all...also had a dead cell in a battery. im not finished but i will check back in this week..thanks for the help
 
Mark Nixon said:
When I did a P pumper into a 1st gen, I grounded the solenoid, ran the start side of the solenoid to the starter solenoid wire and the hold side to the VE pump's switched power.
Never had a single problem with it.

Mark.
Click to expand...

I believe I did it this way too with a p pump into a first gen, and it's been like that for 18 years if the new owner hasn't changed it.
 
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