I would be searching for signs of a break in the power wire for the fuel pump. Assuming power is making it through the relay it shouldn't stop unless there's a break in its path. Could be a corroded connection at the PDC or a break somewhere in the harness but no easy way to find it without tearing about the harness the wire is in. Electrical problems are never easy to hunt down.

 

Or just stretch a new wire. If nothing else to test if it works.

 

Unfortunately, no power is getting to the wiring harness that runs from connector C207 on the driver's side front wheel well to the fuel pump. I need to find out where the 12 volt power is dropping in order to run a new wire. Checking at the bulkhead connector (C116) is my next task as time permits.

 

Well, with the help of a friend that knows more about electrical troubleshooting than myself, we were able to get the fuel pump running and the engine started & running well. Seems that there wasn't good contact with the relay and its connectors in the PDC. Also, ran into a intermittent ground issue for the fuel pump under the PDC. To address it for the short term, my friend grounded the leads coming from the PCM and going to the fuel pump onto the truck's fender, however, I believe this has fried the computer's grounding capability for the fuel pump. It has also caused to fuel pump to stay running whenever the key is turned to the on position (this doesn't seem to good to me, as it could potentially fry a fuel pump if someone leaves the key on for an extended period of time). I plan to pickup a good used PCM and re-join the ground wires for the fuel pump and hopefully put this issue to bed permanently.

If anyone has a spare working PCM (part #56040803), please PM me with pricing and availability.

 

Tons of 56040803s on E-Bay.

 

Thanks. I'm aware of them. Checking everywhere for the best pricing...

 

I’d place reliability above price to tell you the truth. A 27 year old PCM is hit or miss. Find a reputable seller who has some provenance on the unit you’re buying and a return policy. I’m not trying to poo poo price because that’s important too but something as important as a PCM requires a higher level of confidence.

 

I'm quite familiar with the repair game. I'm also selling this truck... Price and basic functionality is what I'm after...

In addition, I may or may not really need another PCM. I have a few more checks to do to fully rule out the PCM as an issue.. I really need to locate the ground source that the PCM uses. Supposedly, it's near the bulkhead connector, but could be under the hood or inside the cab... Anyone have a photo as to where it's really located on a 2WD truck without a towing package?

 

I checked further for the ground wire that controls the ground for the fuel pump and it appeared to be screwed into the firewall area just above and to the right of the bulkhead connector. There was a bit of rust on the terminal connection and the screw that holds the terminal to the firewall, so I cleaned those up really nice and still no fuel pump working. I went ahead and ordered another PCM which should be here sometime next week. We'll see if that takes care of my fuel pump ground issue.

 

On my 95, I had trouble with the 60 pin connector to the PCM. Using the end of a multimeter to do some electrical troubleshooting stretched out the female pins on the connector, to the point that the male PCM pin wasn’t making contact. If the diameter of connector pins for the fuel pump and anti shut down circuits look to be bigger than the others in the connector, you can take the connector apart and gently squeeze the pins back to size.