Hey friends, I really need some help here from you guys. I have a 1988 ford f-150 351w, with an automatic transmission, Two fuel tanks. First off, about 3 weeks ago, my rear fuel tank stopped working, i would switch it over, the gauge would switch properly and show an accurate reading of the gas but the truck would die soon after me switching. Well i could only assume that was the fuel pump, so i put it off. Well today i was driving home on the highway about 70 when all of the sudden, my front driver side tires seperates. The tread came off the tire and beat the crap out of the inner fender. I pulled over asap. Well i switched the tire and then my truck would not start. Whenever i would turn the key to the run position, but not start it, i would be able to here this humm and click everytime (i believe it was the fuel pump). Well now it doesn't do that, The engine turns over fine, but no fire. I'm thinking either the tire tore up wiring, (which i couldn't find any damage) or the pump decided to go at that very minute. What i am needing help with is which one of the pumps is probably bad. I do not hear them kick on anymore. Would they be the ones on the frame Rail? Do you think maybe it beat the relay to death? I'm at a lost for words with this. It is currently 45 miles away at my mothers. I am in stillwater, ok for college (where i live now). I'm hoping to go back in two days and try to get it fixed. Any information from anyone on how to test fuel pumps, what to look for with maybe filters, wiring would be so appreciated. Thank you in advance. I look forward to hearing from all of you!

 

The whacking the fender took from the tire tripped the fuel pump cutoff switch. It's for in an accident the fuel pump shuts off to stop the flow of fuel to prevent a fire. It is inside the passenger compartment on the firewall near the brake pedal. It's a little black box. Just push the button to reset it and you should be on your way. Some are located behind the passenger side kick panel but i believe yours isn't.

 

What he said.

 

Sean is probably right on, if it still won't start though I would check the connectors on that side. On my truck there are 6 or more quick connects that sit on that wheel well on the inside. My EEC relay and fuel pump relay sat there for years too just because they didn't get slid up into their holder. I would check those for dammage, put the key to run and move the wires around, you will know you got it if you hear the fuel pump prime.

 

Great! I will do that when I go home. Now about the rear tank not working. Which of the pumps do you think it might be? The one in the tank, or the one on the frame rail. Hopefully I can get that one fixed asap. Thank you very much guys.

 

I think the rail pump is a booster shaired by both tank pumps, if your is set up that way. My truck is a little newer and only has the 2 pumps in the tanks. Should be a issue with the rear tank pump or you would get no fuel at all.

Sean will explain it better in 30min or less.

 

The in tank pumps are low pressure on trucks with an external pump also. The external pump is a high pressure one. If the external pump was bad, the truck wouldn't run right with either tank. So the bad pump is in the rear tank.