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Explorer EFI swap fuel pump/pcm/wiring problem

toddz69

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I'm showing that as a frame mounted pump. Are you using a frame mount with the explorer efi?
I should've clarified that. The Bosch 044 mentioned earlier is a frame mounted pump too, as is this one.

A good number of folks do use frame-mounted pumps with Explorer EFI but the OP obviously isn't.

Todd Z.
 
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jmart52

jmart52

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Thanks for everyone's help. I figured out and fixed the problem. It was my fault for not being thorough when I changed the pump the last time. Turns out the the tank was rusty and full of gunk. Didn't take long to foul the new pump. I blasted and cleaned the tank perfectly this time. And coated it with KBS tank seal. I went to Quantum fuel systems and got a new pump. It's up and running. Now to work out all the other kinks.
 

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DirtDonk

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You may have said elsewhere on the forum, but what exhaust are you using?
 
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jmart52

jmart52

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Well the fuel pump and tank is fixed. I'm confident about that. I have a slight vibration and stumble everytime i push the gas. I changed the plugs and cleaned the fuel filter. No change. I pulled the codes and the only one was p0340. That has been there from the day I installed everything. The 5 volt reference is only reading 2 volts. It seems to be 5 volts everywhere else. I pulled the the pin from the pcm and checked it there. 2 volts. I jumped a wire from the tps to the cmp and cleared the code. That seemed to clean it up and no stumble. Then the fuel pump started cutting out. I thought it was a loose wire in the fuse/relay block, but everything tested ok. Where i probe the relay and turn the key on there is nothing. Anything else to test or try? Or is the pcm toast?
 
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jmart52

jmart52

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One more thing. I tried swapping in another pcm. Stock, not flashed. Everything was the same. I don't know if it matters that it's not flashed. It's a 96 so I don't think that has pats. Maybe my harness has a problem?
 

904Bronco

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How are your Grounds? Could debris have made its way to the injectors? Did you have the injectors serviced prior to the initial start-up?

Just some random thoughts...
 
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jmart52

jmart52

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How are your Grounds? Could debris have made its way to the injectors? Did you have the injectors serviced prior to the initial start-up?

Just some random thoughts...
I did check the grounds but I'm going to go through them again. The injectors were newly serviced. Once I figure out what the fuel pump isn't firing I'll check the injectors to see if they need to be cleaned.

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jmart52

jmart52

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Fuel pump issue is finally solved! It was a bad crimp on the relay! Now on to getting everything else dialed in on the EFI. Finally. I believe I'm having a tps problem now. I made a mistake way back when I was getting everything from the junkyard. I have a 96 ecm with a 99 harness. That has been the cause of more headaches than ide like to admit. Harness are much harder to find now, or I would just do another harness
20250509_173649.jpg


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