I have a 91 f150 4WD 5.0L reg cab long box originally dual tanks. Rear Tank was removed along with fuel pump. Front Fuel pump does not turn on and will not pump fuel. I dropped the tank and hooked the pump to a battery and the pump worked. I replaced the fuel pump relay. When the key is turned the connector to the fuel pump gets no power. Since i removed the rear tank i checked to see if power was going to the old rear pump wires and it was not. The only fuse box the truck has is under the dash. According to the sticker the only fuel related fuse was the fuel tank selector fuse which is good. I thought there must be a fuel pump fuse but i couldnt find one at all. Any ideas? Its got me stumped.

 

Could be the Inertia switch, try resetting it buy pushing down on the button on top.

If not that does the fuel pump relay click when you turn on the key and then click again one second later when it drops back out of the circuit?

Do you have power at the Inertia switch with a test light when you turn on the key for one second?

 

The fuel pump relay does not click at all and its brand new. The EEC relay does click however. I also reset the inertia switch and the fuel pump still does not operate or get power. Any ideas?

 

The interia switch is getting about 1.9V if that helps

 

Do you have power going to anything on the relay?

 

u could run a new wire to it and put it on a toggle switch like on race cars.... u prolly wont want to do this but i think it would be cool like that especially if u put push button start on it

 

Lol. Thats kind of how my F-350 is set up. My ignition is messed up somewhere along the line. You still need the key to be on, but to turn the truck over you press a button. The key won't turn the truck over anymore so I thought it would be easier to just install a push button. Haha.

 

Short pin #2 to pin #6 of the EEC Self-Test Plug (Connector) and turn on the key.
Does the selected fuel pump now run all the time?




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I jumped the two and the pump still does not run at all. Any ideas?

 

pumps burned up?

 

Did the fuel pump relay click when you shorted pin #2 to pin #6 with the key on?

 

Already tested the pump by hooking it up directly to a battery. pump works. Also when i jumped the two the fuel pump relay still did not click.

 

With the key on check one of the red wires at an injector and see if the test light lights.

 

I just had the same problem, i replaced the ignition switch and it worked.