FUEL PUMP NOT WORKING

  • Tiny
  • mhj2756
  • 1994 Ford F-150

Electrical problem

My 1994 f150 will not start I am sure it is fuel delivery prob it has dual tanks 5.0 engine things I have checked so far I don't have any power at the front or rear tank connectors rear tank has never work their is no power at the selector switch or at the inertia switch their are four relays mounted next to the power dist. Box I change them around I checked all fuses I also grounded the lead of DLC connector had the same prob. One other time I keep turning the ignition off an on till I heard the fuel pump come on thanks if you could help me with this prob.

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Wednesday, October 15th, 2008 AT 2:55 AM

6 Replies

  • Tiny
  • James W.
  • Member

Do you have battery voltage at fuel pump relay socket? Can you hear the fuel pump run for just a few seconds when you turn the key to "ON"?

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Wednesday, October 15th, 2008 AT 3:35 AM
  • Tiny
  • mhj2756
  • Member

Their are four relays I think I have 12 volts at all of them I cant any noise from the fuel pump also I have replaced the ignition switch

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Wednesday, October 15th, 2008 AT 6:02 AM
  • Tiny
  • James W.
  • Member

I'm sorry, but "thinking" you have power to the relays doesn't do me much good. Let's do it this way.
One of the relays of the 4 will have the following color wires. My diagram doesn't tell me which one for sure, but look for these colors. These are the wires going to the relay socket.
1- yellow-12volts from the fuse. No power, the fuse is out.
2- dark green /yellow-power to inertia switch. From inertia switch to fuel tank selection switch, then to fuel pumps.
3- red-12volts from computer when key in "start"position. Not "run", start position.
4 blue/orange-ground from computer with key in "start" position.
TEST; jumper wires 1 & 2. You should now have power to the inertia sw, the selctor sw and which ever tank is selected, that pump should be running.
If not, check power at fuel pump connection at tank. If you have power there, the pump is bad.
If you have access to a fax, give me the #, and I'll fax you a copy of the diagram.

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Wednesday, October 15th, 2008 AT 8:58 PM
  • Tiny
  • NATASHA30122
  • Member

We are having the same problem on our 1994 Ford F150 Single tank no firing and no fire to the fuel pump. Please respond where the fuel relay is located. Is it under the hood or in the truck? Which relay is it? Thank you! Robbie C.

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Sunday, October 26th, 2008 AT 2:52 AM
  • Tiny
  • NATASHA30122
  • Member

Additional information:

Fuel pump relay in fuse panel under hood. Which fuse do I need to replace? Also, my fax number is 770-489-0094. Can you please fax me a copy of the diagram as well. Thank you so much for your help.

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Sunday, October 26th, 2008 AT 2:55 AM
  • Tiny
  • 2CarPros Ken
  • Admin
  • 3,109 posts

These trucks had a big problem with the switching valve which is located between the tanks on the frame rail on the drivers side.

Please let me know how it goes, we are here to help.

Best, Ken

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Tuesday, August 16th, 2016 AT 9:35 AM

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