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I have changed the rear tank fuel pump twice now. Feel pump runs fine for a few minutes and then will pump weak and not accelerate and I have to switch to the front tank for acceleration. At idle it will run longer but eventually will stumble and die on rear tank. I am at a loss on what to look at. I’ll change the fuel filter tomorrow but not sure how that would affect the rear tank only. Any and ask help would be appreciated.
Low voltage at the rear pump will do this. If you put a jumper to ground on the Fuel Pump pin in the EEC TEST connector under the hood and turn the key to run(engine off) the selected pump is continuously powered which should make troubleshooting easier. All wiring in this circuit is suspect because you don't know what may have been done by a previous owner, the wiring at the switch could be a modified or poorly repaired
Thanks for the info. I’ll run it tomorrow and check voltage at pump. I bought the truck in 2012 with 65k miles from the original owner. Pump in rear was the ford original. I don’t think there has been any hack repairs yet on fuel system. Are there any known problem areas to check first?
So older trucks like this suffer from corrosion at connectors and even possible something is rubbing a wire causing a short. so you can use a test light high amp, on the fuel pump connector at the rear pump to see if the wiring supports the load.
Don't know if '96 is similar to 90/91, but check the dash switch. I had one go out (slightly melted plastic causing bad connection.
Drove 50 miles, parked in grocery store parking lot, wouldn't start 20 minutes later. Fuel at rail, but no way to check pressure.
Towed home, and before crawling under, thought I might check the switch. Comes out real easy on mine.Contacts were obviously bad, but allowed enough current through to pump fuel, but not enough pressure to start.
Replacement (Dorman, I believe) was about $50, probably Chinese, so I bought one from an electronics outfit for $10. Fine for over a year now.
Don't know if '96 is similar to 90/91, but check the dash switch. I had one go out (slightly melted plastic causing bad connection.
Drove 50 miles, parked in grocery store parking lot, wouldn't start 20 minutes later. Fuel at rail, but no way to check pressure.
Towed home, and before crawling under, thought I might check the switch. Comes out real easy on mine.Contacts were obviously bad, but allowed enough current through to pump fuel, but not enough pressure to start.
Replacement (Dorman, I believe) was about $50, probably Chinese, so I bought one from an electronics outfit for $10. Fine for over a year now.
tthis vehicle uses a fuel pump relay to handle the power load, but the switch would of course dictate which tank its chosen
