Mechanics

BOTH FUEL PUMPS WOULD NOT COME ON

1994 Ford F-150 • 126,211 miles

Hello I have a 1994 f-150 with a 4.9L and dual tanks. I shut off the truck and it would not start. Both fuel pumps would not come on. The fuel pumps will sometimes both work then when I shut off the truck and then they both wont hum when theyre priming. Ive changed the maxifuse the relay and the inertia switch. I can hear the relay clicking on when I first turn the key on. The only thing I havent changed is the tank selector switch but I took it out and made sure it had a secure fit. And when its working I can switch to either tank with no problem, then both will die. Any help you can offer would be greatly appreciated. Thanks again. Joe
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The switching valve at the bottom is the only thing you have not changed. Check it and see if it is working

Roy
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Thank you for taking the time to help me out. Im not familiar with the switching valve. How would I check it and where is it located? Thanks again

Under the truck. Find the fuel lines and they all come together at one point and the switch will allow one tank at a time to supply fuel.

You need a voltmeter to verify voltage and switching

Roy

Thanks Roy, this is my first time to a mechanic forum and you where very helpful. This valve would have to be the problem I will test it in the morning. Thanks Joe

Good luck

Roy


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