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What is wrong with my under hood fuse box??

Discussion in 'Wrangler YJ (1986-1995)' started by Rhull39, Jun 9, 2019.

  1. Jun 9, 2019 at 7:50 AM
    #1
    Rhull39

    Rhull39 [OP] Member

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    So for a while when I turned the key in my Jeep it would take about 20-30 seconds for the fuel pump relay to start clicking and it would click repeatedly for about 10 seconds or so until the pump came on and it started. The colder it is the longer the relay takes to start clicking and the pump to prime the system Yesterday the relay wouldn't click and the fuel pump wouldn't pump at all. I switched relays and nothing. The only way I can get the fuel pump to work is by jumping it with the closest relay next to it which is the auto shutdown relay. That tells me that the wiring from the fuel pump relay to the pump is ok. What the heck is happening here? Thanks in advance.
     
  2. Jun 9, 2019 at 8:03 AM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    Welcome to the site! Sounds like you might have a bad connection to the relay, but Im not good with electronics. Hopefully someone with more experience will chime in.
     
  3. Jun 9, 2019 at 8:44 AM
    #3
    Awrench

    Awrench Well-Known Member

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    We would use a wiring diagram and a test light - before getting that info and needed diagrams to you (takes time) tell us your skill level - in the trade, a DIYer, where do I add gas?
     
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  4. Jun 9, 2019 at 8:44 AM
    #4
    aggrex

    aggrex Well-Known Member

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    Welcome @Rhull39 getting it to work by jumping with the closest relay is a good sign. Continue with voltage and ground inspection.
     
  5. Jun 9, 2019 at 9:26 AM
    #5
    Rhull39

    Rhull39 [OP] Member

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    I'm a pretty experience DIY. Wiring not my thing though. Any idea where the grounds for that fuse box are located?
     
  6. Jun 9, 2019 at 9:58 AM
    #6
    Awrench

    Awrench Well-Known Member

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    fuse box would NOT be grounded - the component it supplies would have ground, ie o2 heater and then we woild pull that o2 heater diagram to locate its ground.

    I will post some ideas and diagrams time permitting, soon.
     
  7. Jun 9, 2019 at 10:15 AM
    #7
    Awrench

    Awrench Well-Known Member

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    tmi: LET ME KNOW IF YOU CAN FOLLOW DIAGRAMS. Did not draw arrow to FP relay B location by ASD location

    Starting with ASD
    wjth test light probe cavities 21 and 22,
    22 hot all times.
    21 hot with key ON and in start - did the 12v appear quick or lag @20 seconds? as mentioned

    Move on to testing fuel pump cavities 6,7

    I am thinking a ign switch problem... no 12v on fused ignition BUT a guess right now.



    Sorry for sticky cap key.

    95  YJ ASD.jpg
    ASD pinout.jpg
    fuel pump pin out.jpg
     
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  8. Jun 10, 2019 at 7:43 AM
    #8
    Rhull39

    Rhull39 [OP] Member

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    It's seems you were correct. Tested all the relays and they were good. So moved in to the coil and that was good. So we tested the ignition fuse and that was good but there's no spark from the distributor while cranking. There's a wire that runs under the distributor cap. I wiggled it and fuel pump kicked on. I took the cap off and tried to get at the connector behind the distributor which is near the block. Couldn't get at it and it's pretty caked in oil. What's your advice? Take the distributor off and clean it up? Does the engine need to be at TDC to pull the distributor? Also as another note, when I would jump the relay to make the fuel pump run it wouldn't fire when I turned it over.
     
    Last edited: Jun 10, 2019
  9. Jun 10, 2019 at 9:09 AM
    #9
    Awrench

    Awrench Well-Known Member

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    restate your issue - no start -
    when cranking is there
    spark?
    12v at injector?
    12v at coil?
    did you check codes? maybe a clue.

    The dist has a 3 wire harness IIRC... you say just 1 wire, you mention runs uneder dist OR into dist? if running under can you find its termination ?

    This is a 1995 wrangler 6 cylinder ?
     
  10. Jun 10, 2019 at 9:41 AM
    #10
    Rhull39

    Rhull39 [OP] Member

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    It's a 95 4 cyl. 12 v at coil and when I run the fuel pump I can purge fuel at the rail. Not sure if that means I have power at the injectors. The distributor has a 3 wire attached setup that runs under the cap and then behind the distributor too near the engine block for me to get access without removing the distributor. It looks like the ground is possibly the same bolt that holds the oil filler tube. The diagram you sent looks like a 6 cyl wrangler but was helpful. I did neglect to check 12 v to the ignition fuse. I will do that and get back to you. I can do body work, suspension setup and everything under hood minus a full engine rebuild but can't do this wiring baloney. Thanks so much for your help. This is my daily.
     
    Last edited: Jun 10, 2019
  11. Jun 10, 2019 at 9:51 AM
    #11
    Awrench

    Awrench Well-Known Member

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    I hate HATE these old mickey mouse jeep wiring diagrams....
    I will let you have a OEM manual wiring section rather than having to search the BS.

    Hope it helps. Let us know I will follow along and try to help.

    PS: After many years wire colors tend to 'bleach' so tan may be yellow, gray appears as white etc....
     

    Attached Files:

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  12. Jun 10, 2019 at 9:54 AM
    #12
    Awrench

    Awrench Well-Known Member

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    FYI: the fuel pump relay will only energize the fuel pump for @3 seconds if the engine is not running.
    Makes testing the circuit tough when alone.
     
  13. Jun 10, 2019 at 10:48 AM
    #13
    Rhull39

    Rhull39 [OP] Member

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    Thanks for your help.
     
  14. Jun 10, 2019 at 10:53 AM
    #14
    Rhull39

    Rhull39 [OP] Member

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    All the relay seem to be good. All the fuses seem to be good. I don't know what else it could be. Any ideas?
     
  15. Jun 10, 2019 at 11:09 AM
    #15
    Rhull39

    Rhull39 [OP] Member

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    When I connected the leads for the relay all together while off the relay the pump ran continuously
     
  16. Jun 10, 2019 at 12:23 PM
    #16
    Awrench

    Awrench Well-Known Member

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    twisting the bundle of wires together would make the pump run. bUT THAT IS NOT NORMAL,

    BASICS
    With KOEO key on eng off
    is there 12v at coil?
    Is there 12v at injectors?
    What is fuel pressure - will need a gauge....
     
  17. Jun 10, 2019 at 1:18 PM
    #17
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    I would check this wire for continuity and connectivity. Unless I'm missing something?
     
  18. Jun 11, 2019 at 11:52 AM
    #18
    Rhull39

    Rhull39 [OP] Member

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    I have 12 v at the coil but I have no spark or fuel pump now. Are they dependent on each other with the way the relays are set up? I'm at a loss.
     
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