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Both fuel pumps will not turn on

Tiny
DAEDRIC
  • MEMBER
  • 1988 FORD F-250
  • 5.8L
  • V8
  • 4WD
  • AUTOMATIC
  • 190,000 MILES
Few weeks ago my truck set for two days then I go to start it it cranks but no start. I listened for the fuel pumps to kick on and neither one of then kick on at all. They both stopped working. Any ideas would be appreciated. Thank you
Thursday, December 6th, 2018 AT 8:17 PM

9 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

Do you have a test light or voltmeter to do some checks?

We need to verify power to the inertia switch to be sure there is power coming from the relay.

I attached a wire diagram for the system, but we have to be sure there is power to the switch. When you turn on the ignition, it will only be there for two seconds. If you crank it, it should have constant voltage.

Roy
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Friday, December 7th, 2018 AT 8:17 AM
Tiny
DAEDRIC
  • MEMBER
  • 5 POSTS
I have checked the relay. I checked the switch everything is getting power but not the pumps, both of them do not kick on. Thank you for the reply.
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Friday, December 7th, 2018 AT 11:08 AM
Tiny
ASEMASTER6371
  • MECHANIC
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Okay, back to my question, do you have power to the inertia switch?

We need to do this in stages to find where the power is lost.

Roy
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Friday, December 7th, 2018 AT 11:10 AM
Tiny
DAEDRIC
  • MEMBER
  • 5 POSTS
Yes it does have power even my father tested it.
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Friday, December 7th, 2018 AT 11:31 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, then the next stop is the tank switch. The red/white wire should have power when the inertia switch is closed. Can you verify that?

Roy
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Friday, December 7th, 2018 AT 11:34 AM
Tiny
DAEDRIC
  • MEMBER
  • 5 POSTS
That was the second thing I checked. Could it be the wires running to the pump themselves? So far everything I checked has been working fine.
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Friday, December 7th, 2018 AT 11:49 AM
Tiny
ASEMASTER6371
  • MECHANIC
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Again, will you answer my question on power to the switch?

If you want me to help, I need information in order to get you to a resolution.

Roy
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Friday, December 7th, 2018 AT 11:56 AM
Tiny
DAEDRIC
  • MEMBER
  • 5 POSTS
I just figured out the problem a wire was pulled loose and now their turning on. I am very sorry if this was a waste of time. I do appreciate the help.
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Friday, December 7th, 2018 AT 1:35 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
No worries, we are here to help.

Roy
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Friday, December 7th, 2018 AT 2:01 PM

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