Need a little advice 87 b ll with 93 exp 4.0 swap

[moosemeadows]

Ok here we go. Got a 87 Bronco ll with a transplant 93 Explorer 4.0 manual. Was completed 6-7 years ago after alot of hair pulling ,calling wife to come rescue me, and a few calls to AAA. All together have a little over 100k on the setup. It's ran reliably for all these years until last Thursday when it died along the road. Acted like no fuel so called the wife to come gather me up, again, so I could grab the Chevy and tow bar to get her home. Got home hooked up fuel tester 0 PSI. Does the crank no start thing. The rear tank pump runs but the frame rail one doesn't. Did some tests that came to conclusion the frame pump was no good. Went to get a new pump and was going to install it today but thought another test was needed making sure there's power at pump connection. Low and behold no 12v power but got 6.8 volts on the ground side. I'm no way any good at electrical diag so I come here looking for some suggestions and maybe a process to check things to help get my Bronco ll back up and running. Here's what I can remember doing so far. Pulled the fuel pump relay checked for power have it at relay, went to inertia switch no 12v with key on. I watched a video with a guy working on a 87 Ranger with a similar issue going thru step by step and I got to the inertia switch part that failed so going further didn't make sense. Thanks in advance for your thoughts, suggestions, and encouragement.

 

[alwaysFlOoReD]

I'm terrible at testing and diagnose electrical. But, I've had many of those years dual pump systems and almost every one would eventually have a problem with the in frame pump. I figured out that the spade connectors would come loose over time and give the same problems you're experiencing. My solution was to cut the old spade terminals off and install new ones. You will have to take the in frame pump out, remove the rubber covers to expose the spade terminals.

 

[broncc]

Any voltage on the ground side is bad. Clean your grounding connection and replace the wire if its in poor condition.

Doesn't hurt to undo and redo every plug between the pump and the battery as well. Sometimes the connections get funky.

 

[moosemeadows]

I'm terrible at testing and diagnose electrical. But, I've had many of those years dual pump systems and almost every one would eventually have a problem with the in frame pump. I figured out that the spade connectors would come loose over time and give the same problems you're experiencing. My solution was to cut the old spade terminals off and install new ones. You will have to take the in frame pump out, remove the rubber covers to expose the spade terminals.

Thank you Sir for the advice and I'll do that today. A great place to start.

 

[moosemeadows]

Any voltage on the ground side is bad. Clean your grounding connection and replace the wire if its in poor condition.

Doesn't hurt to undo and redo every plug between the pump and the battery as well. Sometimes the connections get funky.

Thank you Sir for the reply and advice. I remember when this project started all the issues with grounds and the steps necessary to fix them. Thank you again.