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75 sitting idle - won't fire

Discussion in 'Intermediate CJ-5/6/7/8' started by luvdabeach23, Jul 6, 2010.

  1. Jul 6, 2010
    luvdabeach23

    luvdabeach23 Making an honest attempt

    Purcellville, VA
    Joined:
    Aug 1, 2006
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    33
    All-
    My 75 has been sittle idle for awhile out in the elements; won't admit how long 'cause I'd probably be booted from this forum. Basically, she won't fire. I've replaced the plugs and wires and dumped some gas stabilizer in her but still no spark.
    Any brilliant ideas?
     
  2. Jul 6, 2010
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Aug 10, 2003
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    Spark? Pull the coil wire, hold it near the block and crank to see if you are getting spark.

    A '75 has the troublesome Prestolite ignition, so ignition failure is a good possibility.
     
  3. Jul 6, 2010
    luvdabeach23

    luvdabeach23 Making an honest attempt

    Purcellville, VA
    Joined:
    Aug 1, 2006
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    One more thing I forgot to add in my original post; I tried some starting fluid at the beginning of the summer and the engine fired once but then nothing.

    Thanks for the response - I will try this - makes a lot of sense. To further my education - what's the reason I'm holding the coil wire near the block?
    If nothing else, I'll probably replace the ignition coil - something other than Prestolite I figure.
     
  4. Jul 6, 2010
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Sudden no-start (nothing - no pop, no nothing) is 99.9% likelyhood either no fuel or no spark. You have fuel ... so you need to test for the presence of spark. Spark + fuel = boom.

    The spark has to travel to ground somewhere. The block is a convenient grounded surface. You are interested in seeing the spark jump the gap from the wire to the block. This will demonstrate that you "have spark." You should get a good blue-white spark that jumps at least a 1/4" gap. Use something well insulated to hold the wire - a pair of chopsticks or something similar.

    The coil in these cars is just an ordinary coil. The Prestolite parts are the distributor and the gold ignition module on the passenger fender.

    Prestolite ignition module:

    [​IMG]
     
    Last edited: Jul 6, 2010
  5. Jul 6, 2010
    groove93

    groove93 Member

    Bradenton, Florida
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    Apr 18, 2004
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    If you check the coil wire and have spark, you can also stick a screwdriver in a spark plug wire and hold it near the engine block during ignition. You should expect to see a spark jump the gap. This will tell you that your distributor is conducting properly.
     
  6. Jul 6, 2010
    pathkiller

    pathkiller Member

    Lorton, VA
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    Apr 17, 2005
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    878
    Tim, you forgot a very important part of the equation: air. Spark + Fuel + Air = boom. Spark + fuel in the absence of oxygen= nothing. The air part of the equation amounts to making sure the choke isn't stuck shut or rats haven't built a nest in the air cleaner (since it's been sitting a while this is a strong possibility). If you eliminate these elements, fuel, spark and air, one by one you can find out why it's not starting.
     
  7. Jul 6, 2010
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    AughH! Criticism! :beer:
     
  8. Jul 6, 2010
    luvdabeach23

    luvdabeach23 Making an honest attempt

    Purcellville, VA
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    Posted via Mobile Device
     
  9. Jul 6, 2010
    luvdabeach23

    luvdabeach23 Making an honest attempt

    Purcellville, VA
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    Aug 1, 2006
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    Took one look at the coil and decided to replace it. Didn't test as recommended and now the results are same - just turning over. But am not sure about the ignition wire from coil to distributor - doesn't seem to seat properly on new coil. Checked manufacturer website and is correct part.
    All wires look to be in good shape but I can't remember if I replaced them since she started last.
    Posted via Mobile Device
     
  10. Jul 7, 2010
    pathkiller

    pathkiller Member

    Lorton, VA
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    Consider it peer review.
     
  11. Jul 7, 2010
    nwedgar

    nwedgar Now with TBI!

    Newnan, Georgia
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    Oct 26, 2005
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    1,785
    Tim has peers? I thought he was in a class all to himself.

    {sorry for the sidebar...now back to your regularly scheduled thread}
     
  12. Jul 31, 2010
    luvdabeach23

    luvdabeach23 Making an honest attempt

    Purcellville, VA
    Joined:
    Aug 1, 2006
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    UPDATE:
    Am working on the ignition system and trying to install new points. I get the wheel/spoke-like part out of the way to access old points?
    I have pics but can't seem to figure out how to attach.
    Also found that my fuel neck is totally coroded and has a hole in it.
     
  13. Jul 31, 2010
    rusty

    rusty Well-Known Member

    norfolk,va
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    Dec 16, 2006
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    1,652
    Your ignition system does not have points, If it is a prestolite. It uses that gold box on the fender to trigger the spark.
     
  14. Jul 31, 2010
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    If you go to the "Forum help and testing" there is a sticky from Sparky that explains how to post pictures. You don't have points with electronic ignition. That is what has us confused. Pictures will be needed to see what you are trying to do. HTH
     
  15. Aug 1, 2010
    uncamonkey

    uncamonkey Member

    Greeley CO
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    Jun 2, 2009
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    I think that now there is a sticky at the top of all forums, after you click in, above the black bar, regarding picture posting info.

    If I can do it, it can't be too hard.

    Still working on the avatar...
     
  16. Aug 9, 2010
    lhyatt

    lhyatt Member

    southern,Ohio
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    "The Jeep bible", probably the best money I've spent on my Jeeps.Good luck,
    Larry
     
  17. Aug 21, 2010
    msarge

    msarge In Progress 1974 CJ5

    Hilliard, Florida
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    12 volts to ignition module?
     
  18. Aug 15, 2016
    luvdabeach23

    luvdabeach23 Making an honest attempt

    Purcellville, VA
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    Aug 1, 2006
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    Hey...can I resurrect an old strain back to life after 6 years?
    So I finally got my 75 back home after nearly 3 years in storage and then another year sitting in the garage since.
    The evening I moved her from storage she showed signs of life. On a whim I brought along a new ignition module and swapped it out and she started right up and ran about 10 minutes before I shut her down and towed her home (10-15 minutes). But once I got her home she wouldn't start up again. Since then I changed the coil, gas tank and fuel filler, and blew out the lines. She'll crank and crank all day but get no spark. Yesterday I went through the ignition troubleshooting from the manual; I have 12v at the coil but am not getting anything extra when cranking. Says the test light will flicker when cranking but I just get solid. So supposedly that means the ignition module being bad (?) AGAIN...so I'm leaning towards the D.U.I. distributor. Any thoughts?
     
  19. Aug 15, 2016
    zila

    zila I throw poop

    Rock Springs,...
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    I have a 75... I finally gave up on the Prestolite. I used to carry 2 ignition modules.. I installed an HEI ignition when I went to TBI.. Never misses a beat. I still carry a spare HEI module just cause... Old habit..

    FWIW I still have 2 Prestolite ignition modules sittin in the shop..
     
  20. Aug 15, 2016
    luvdabeach23

    luvdabeach23 Making an honest attempt

    Purcellville, VA
    Joined:
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    Mighty kind; if I go that route I'll let you know. A buddy of mine recommended replacing both the coil and ignition module together - and then who knows how much longer the distributor will hold up. So at this point I'd rather make the investment and get a simple, long-term solution.
     
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