Fuel Pump Relay *HELP*

Discussion in 'Electrical' started by 2004300K, May 21, 2018.

  1. 2004300K

    2004300K Member

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    Hello, I have a 2004 Ford Expedition that has been giving me some problems. It was running fine and then one day I turned it off just to try and restart it but no luck. It’s not getting fuel to the engine. I did the research and soldered a new micro relay on the fuse board. Put it back in the truck and it started up right away, but right after I turned it off and tried to restart it the truck was doing the same exact thing as before. No pressure to the rail and cranks over without starting all. I’m wanting to know what would cause the relay to go bad after one start. I’m reaching the end of my road and I’m going to ether give up on my baby or I’m going to have to jerry rig the fuel pump wires around the fuse box. Any help would be of much help!
     
  2. stamp11127

    stamp11127 Super Moderator Staff Member

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    Welcome to the site.

    The only way a relay would fail is too high of a load. What is the rating of the relay. How did you make the connections?
     
  3. 2004300K

    2004300K Member

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    It’s the same relay that came from the factory but I’ve read those often go out right after replacement. I’m thinking of buying a upgraded relay if nothing else works, and I used rosin core solder. The solder joints look fantastic.
     
  4. stamp11127

    stamp11127 Super Moderator Staff Member

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    Trouble shoot the control side of the relay to make sure it is getting power. The pcm will ground the control side for @2 - 3 seconds waiting for input from the crank sensor. If a minimum rpm threshold is reached the pump will stay on, if not the pump is turned off.

    Also check the load side to make sure it is getting power. It will be hot with the ignition in the run position - pin #3 or 30 depending who made it.
     
    Last edited: May 22, 2018
  5. 2004300K

    2004300K Member

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    I assume it is getting power since it did start right after I replaced the relay and ran perfectly fine. It seems like the relay just went out again. It is doing the same thing as before, and right after I replaced it it was working perfectly tell I turned it off and tried to restart it.
     
  6. stamp11127

    stamp11127 Super Moderator Staff Member

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    I'll tell you what I tell my students:

    Verify, verify, verify - don't assume sheet. Get the meter out and prove it either has or doesn't have power.
     
  7. 2004300K

    2004300K Member

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    That’s what I’m saying. Every time I use a test light or meter everything tests perfectly fine. I’m really hoping it’s just a bad relay at this point. Doesn’t seem like it could be much else.
     
  8. stamp11127

    stamp11127 Super Moderator Staff Member

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    This is the first time you have said anything about using a test light or meter.

    Jump 30 to 87 and see if you are able to crank & run. You should get a spark when you install the jumper. This bypasses the pcm control of the fuel pump.
     
  9. 2004300K

    2004300K Member

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    Sorry. I was half asleep when I wrote the OP. Yeah I’ve done all the testing before I replaced the relay in the first place. I will do that jump though! It will narrow things down.
     

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