Both fuel pumps would not come on

Tiny
PASEFLOORS@GMAIL.COM
  • MEMBER
  • 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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Monday, June 4th, 2012 AT 1:26 AM

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Tiny
ASEMASTER6371
  • EXPERT
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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Monday, June 4th, 2012 AT 1:28 AM
Tiny
PASEFLOORS@GMAIL.COM
  • MEMBER
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
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Monday, June 4th, 2012 AT 1:33 AM
Tiny
ASEMASTER6371
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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
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Monday, June 4th, 2012 AT 1:40 AM
Tiny
PASEFLOORS@GMAIL.COM
  • MEMBER
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
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Monday, June 4th, 2012 AT 1:48 AM
Tiny
ASEMASTER6371
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Good luck

Roy
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Monday, June 4th, 2012 AT 1:50 AM

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