HELLPPP!! FUEL PUMP WILL NOT WORK

Discussion in 'The Garage' started by Will Rey, Sep 14, 2020.

  1. Will Rey

    Will Rey New Member

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    Hey guys I’ve literally tried everything to get my mustang to run. So I’ll fill you guys in to see if I missed anything. I bought a 1996 Mustang 3.8 with a 4.6L swap. The day I went to buy the car the guy dropped it on his jack trying to put the tires back on and dented the oil pan. But I still insisted to ask to run the car even tho it prob was hitting the crank. The car ran for about 3 seconds and then I turned it off. Then I let the car sit for about 2 weeks until I had money. I got the parts to replace the pan and did it and when I went to crank the car, the car wouldn’t turn over. So I took off the fuel line and started the car and little to no fuel came out. So I suspected the pump was bad so I replaced the pump and still the same issue. I attached the negative lead to the negative side of the battery that was connected to jumper cables and checked the fuse box and I’m getting 12v and I checked the plug to the fuel pump and I’m getting the proper readings. I checked the side of the passenger door for the fuel pump relay and I saw it was missing it so I bought a relay and plugged it in thinking that was the issue but it didn’t solve it. Then I read somewhere that I should check the FPDM but I looked where it is suppose to be and it’s not there so I think my car doesn’t have one. My last bet is to replace the CCRM but I thought I would hop onto the threads to see if I missed anything. Also I took it to a shop and they also told me the fuel pump was bad and that’s why I replaced it but I’m guessing that wasn’t the issue so if anyone has any input that can give me that would help :))) I’ll also upload videos and pics tm for references
     
  2. 96blak54

    96blak54 Legend

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    That inertia switch is somewhere! Go fish!

    My 96 is located trunk tail light wall to the left. Youll need to remove some wall interior, possible trunk latch beauty panel. Dig in and find it!

    Be sure to report back if it was the inertia switch
     
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  3. Will Rey

    Will Rey New Member

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    Sorry I forgot to mention that yeah I checked the inertia switch it’s pressed down.
     
  4. RAU03MACH

    RAU03MACH Well-Known Member

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    First you should not disconnect the fuel Line to check for fuel
    Thats what a fuel psi gage is for testing
    Like @96blak54 said check the trunk for your inertia switch
    Pink with blue stripe positive wire
     
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  5. 96blak54

    96blak54 Legend

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    Might want to double check power flowing thru the switch. Then maybe apply power straight to the pump just to see if it will in fact run.
     
  6. ttocs

    ttocs Post Whore

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  7. Will Rey

    Will Rey New Member

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    How would I apply power straight to the pump?
     
  8. apsmith49921

    apsmith49921 Active Member

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    Use a car battery with leads attached to the terminals.

    Edit: just realized it's possible the fuel pump doesn't run off a full 12v. Can someone chime in?

    My suggestion is to start at the plug that plugs into the pump. Check for voltage and make your way backwards until you find power.

    Sent from my SM-G955U using Tapatalk
     
    Last edited: Sep 15, 2020
  9. Benni614

    Benni614 Member

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    Ok. Did u check signal to the inertia switch
    Fuse relay. Can u manually prime the pump if so the u know wires you tested are good up to the component you bypassed

    Sent from my SM-N975U using Tapatalk
     
  10. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    You said you checked the wires at the pump and got a proper reading? What exactly did you check? If you have voltage and ground at the pump connector but the pump doesn’t run, then the pump is bad or has a bad connection inside the tank.
     
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  11. Will Rey

    Will Rey New Member

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    Ok thanks will try it all out
     
  12. ttocs

    ttocs Post Whore

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    this is easy to do there should be 12v on both wires. If the switch was either bad or had a bad connection it would do this
     
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  13. Will Rey

    Will Rey New Member

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    So here the updated the first picture is the reading from the fuse and the video is when I put the negative lead and positive lead into the fuse it gives me a mV reading that goes up to 400 mV then drops and goes back up. Then I checked the plug into the fuel pump in the next two videos. One prong gives a mV reading that goes up then back down and repeats. One prong gives me a .4 V reading. One prong gives me a 11 V reading and the last prong gives me a 6.7 V reading. I don’t know how to check the volts coming out the inertia switch. Another thing to mention I don’t have a FPDM where it should be. I’ll attract a photo. All that is plug into there is my keyless entry in the back. There’s on wire that is suppose to be plug into something but I can’t find what plugs into it anywhere online.
     

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  14. RAU03MACH

    RAU03MACH Well-Known Member

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    I have 1 question
    When you removed the oil pan that you stated
    Was there a wire harness under the front oil pan
     
  15. bigmike636

    bigmike636 New Member

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    I’m not sure why you would check the fuse by inserting the negative lead and the positive lead into the fuse. If I were you, I’d keep the negative lead on the negative battery terminal. Then I would place the positive lead on one side of the top of the fuse, where the metal extends above the fuse. Then place that same positive lead on top of the other side of the fuse. If you have 12 volt power on both, it would appear that the fuse is good. If you actually pull the fuse, you can test it by placing the VOM into the resistance mode. Then you would take one lead and place it on one leg of the fuse and place the other lead and place it on the other leg of the fuse. If the fuse is good, your resistance reading should read close zero ohms of resistance. If however the fuse is bad, you would see a high resistance value.


    Sent from my iPhone using Tapatalk
     
  16. RAU03MACH

    RAU03MACH Well-Known Member

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    What I'm thinking is he might have created a similar problem
    With wire harness at the bottom of the oil pan
    All those wires are at the side by the battery and fuse box
     
  17. RAU03MACH

    RAU03MACH Well-Known Member

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    including oil psi switch sensors
     
  18. bigmike636

    bigmike636 New Member

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    I know that I may be comparing apples to kumquats here, but my daughter had an issue with her Mercury Mariner (3.0 Liter V6) not starting. When I checked the connector to the fuel pump for voltage, I thought I had 12.6 volts to it. But before I replaced the pump, I checked to make sure that she had a good ground to the pump connection and I found that she didn’t. I had 12.6 volts power, but no ground. It wound up being the crappy aftermarket fuel pump driver module that I replaced on it three weeks prior. After I replaced it with a new Motorcraft one, the pump fired right up.


    Sent from my iPhone using Tapatalk
     
  19. RAU03MACH

    RAU03MACH Well-Known Member

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    Could be
     
  20. Will Rey

    Will Rey New Member

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    I will check for that later but I’m pretty sure there was