Starting a fresh thread on this specific issue, here it goes.

Truck specs:
1995 F250 2WD
Rear tank only
4.9 / automatic

Symptoms:
Truck came to me with power loss/missing under medium-hard throttle.

Fuel pump was putting out 35 PSI at the shrader on the rail, book calls for 55-60.
Installed a new pump, the new pump primes and stops like it should, but shows 0 psi at the shrader. I removed the fuel line at the filter and verified that the pump is moving fuel when priming and moving fuel when cranking BUT it's just pissing out of the line, good volume but not really spraying out, I would expect it to be rocketing out since it's supposed to be able to achieve 60 psi. I reinstalled the fuel line and tried over and over to get fuel to reach the shrader and only was able to get a little dribble one time.
I sprayed some maf cleaner in the intake to get the truck started to see if I could get the voltage/run cycle to excite the pump but it just runs on the cleaner and dies once it's gone.

I didn't re-wire anything and only had to wire the black and red wires in the tank (which are very well connected)

Another noteworthy mention is the gauge now reads 1/2 tank with the key OFF and empty with key on... Why?
The gauge worked before and should be showing 1/4 tank.

I did NOT modify the sending unit wire, just unscrewed the sender and screwed it back to the new pump.

Any help is appreciated, I'm stumped.

Also, if I wanted to run a 12V jumper wire to the pump directly, what pin should I use on the plug? It's a round/square 4-pin plug.

For the life of me I can't figure how the heck it went from a weak pump to zero psi with the new one... Maybe it's a bad pump? It does pump, just very weak.

 

I grounded the #6 pin on the EEC and the pump runs, sounds strong but zero PSI at the rail, fuel still comes out of the filter... Mother of god, what's the deal? I'm starting to thing this pump is trash. I don't know what else it could be. I'm gonna reinstall the old pump and test it since it worked, if it runs 35 psi again then I have my answer.

 

I would bet you got a bad pump. Just think of it this way If someone came to you and Described the same issue you would tell them the same after a few other tests to reaffirm the problem.

 

I thought that exact thing, but I feel like I jumped the gun.

Here's what I THINK I've discovered, The factory pump had a 30° angle cut where the sock goes and it allowed it to sit in the sump now the new pump is square cut on the bottom and does not have the 30° angle therefore it puts the sock at more of a straight angle up out of the sump and I got under the truck I was listening to it and I could hear it gargling a little bit while the pump was grounded and running continuously so for the heck of it I disconnected the plug and let the fuel run back into the tank plugged it back in while I was still grounded and I could hear it pick up Fuel for a second and then start gargling again. After that little experiment suddenly I had fuel pressure and not only that I had 60 PSI. So I've added some fuel disconnected the ground from Pin 6 and then started the truck and ever since I seem to have good fuel pressure and it most definitely improved from the original pump I just think this truck may have a new empty level now that the sock is in a different position.

And now I have added five more gallons and my gauge is still showing empty so there is a new issue I have to address honestly kind of at a loss for that since I did not modify the pick up unit wiring at all.

 

Does the truck have the single or dual tanks? Please don't take this the wrong way but are you sure you got the right pump for the TANK? Cause these trucks had I think 3 different tank sizes.

 

Supposedly this is the pump for this tank (19 gal rear only) according to the carquest book. And I started thinking about my 97 with a 7.3 that uses the same rear tank and I remembered that when I reinstalled the sender it had about 6 gallons in it but registered empty until I filled it, almost like the sender was stuck/traumatized. So on a hunch I took this truck to the gas station and put 5 gallons in it and drove over some bumpy roads and she seemed to snap back to life and reads correctly once again. Whew! Hopefully this is behind me now lol

 

Glad you got it sorted out

 

Me too, this truck had so much rigged up stuff when it got to me and it was one thing after another. Runs like a new truck now.

 

Isn't that the way it goes you fix one problem only to uncover another.