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Ford F150 - not getting fuel

I have a 1991 Ford F150. It stalled while driving, like it ran out of gas. I've since replaced the fuel pump relay, fuel pump, and fuel filter and still can't get it to start.
<br/> Any ideas? I'm at a loss.


  • edited April 2010
    First things first. Are you really sure that this is just a fuel delivery problem? A quick way to tell is to spray starting fluid into the throttle body or air intake while cranking the engine. If it fires up a little bit, then you can assume that fuel is the problem. If it doesn't, then it will be ignition or ignition and fuel.

    Is the PCM getting power?
    Is the fuel pump getting power? Is it running? What is the fuel pressure at the rail?
  • edited April 2010
    Engines need fuel, air and spark. Sounds like you got the fuel covered so let's move on to air and spark. Air is usually a given so have you checked the spark? Some of these engines use a ballast resistor which can be problematic. I bet you have little or no spark.
  • edited April 2010
    Actually, I think that 91 used the TFI module. I don't think those used ballast resistors.
  • edited April 2010
    I was able to get the truck to turn over when I used starting fluid. I also disconnected the fuel filter to see if I could get fuel to pump out. No fuel came out of the line when I turned the key on.

    I also need to mention that this is the front tank on a dual tank system. I also tried switching to my rear tank with no luck.
  • edited April 2010
    Okay, that's good information. Do you hear either of the fuel pumps running? Can you measure 12V power at either of the fuel pumps?
    Basically, if the fuel pumps aren't getting power, then the next checks are:
    Are all related fuses good?
    Is the fuel pump relay or relays getting power?
    Is the inertial fuel pump cut-off switch passing power like it should and not tripped?
    How about the fuel tank selector switch?
  • edited April 2010
    It isn't the fuel tank selector.
    From what I can tell, the fuses are good.
    I didn't hear the fuel pumps running.
    At the moment, I don't have a way to check the voltage on the relays.

    Is the inertial fuel pump cut-off switch passing power like it should and not tripped?

    Not sure how to check this
  • edited April 2010
    I just located and checked the inertia cut-off switch. I disabled it and re-enabled it with no luck.
  • edited April 2010
    Look at the diagnostic connector under the hood where codes are pulled. There should be a tan wire with a green stripe. Run a jumper wire from that terminal to ground.
    You should hear the pump run and the truck should start if this is a lack of fuel problem.

    If the truck does run then disconnect the jumper wire. This means that for some reason the fuel pump relay is not getting a ground through the ECM.
    This could be caused by a faulty TFI ignition module, faulty ECM, etc.
    If it does not run then it's very well could be a faulty pump relay.

    Take a test light and connect it to that tan/green wire in the diag. connector. Turn the key to the RUN position. The light should be on. If not, likely a faulty ECM circuit.
    If the light is on, crank the engine over a bit. After 3 or 4 seconds of cranking the light should still be on. If not, a likely TFI module problem.

    (I should have added that pulling the codes might not be a bad idea just in case there is a loss of PIP code; this being the signal the TFI module sends to the ECM which then triggers the pump relay based on that signal.)
  • edited April 2010
    I think it would be well worth it for you do buy a DMM (a $25 one should be more than good enough) and to get some wiring diagrams for your truck. Also, be sure to try OK's suggestion below.
  • edited April 2010
    All engines in the 1991 model year used a ballast resistor (ballast wire) (resistance wire) for the F-150 2 and 4 wheel drive models. If you are not getting spark then I would check out this wire. This is a pretty common problem when the engine shuts down without warning.
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