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134CI Fhead engine IGNITION PROBLEMS

Discussion in 'Early CJ5 and CJ6 Tech' started by TjWheelin85, May 23, 2005.

  1. May 23, 2005
    TjWheelin85

    TjWheelin85 New Member

    Reisterstown, MD
    Joined:
    Nov 30, 2004
    Messages:
    23
    Hey guys, i'm not getting any spark on the spark plugs, 2 new batteries, all hooked up correctly, engine is turning over but not getting any spark???


    Anyone know where i can find some information for trouble shooting.

    Thanks
    Alex
     
    TjWheelin85, May 23, 2005
    #1
  2. May 23, 2005
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
    Joined:
    Sep 20, 2002
    Messages:
    9,221
    Start with the points and condensor.

    They in good shape? New?

    Gap set properly, dwell is important too.

    You should be able to check and see if you're getting spark across the points with the cap off.
     
    sparky, May 23, 2005
    #2
  3. May 23, 2005
    TjWheelin85

    TjWheelin85 New Member

    Reisterstown, MD
    Joined:
    Nov 30, 2004
    Messages:
    23
    my dad said the points are a little cruddy, didn't say anything about the condensor, so i'm ordering new points in the morning, new spark plugs. and now maybe a condensor too.

    Gotta love my procrastination, i leave for a trip thursday evening and this engine is killing me.
     
    TjWheelin85, May 23, 2005
    #3
  4. May 23, 2005
    gte636p

    gte636p Member

    smyrna, Ga
    Joined:
    Sep 23, 2002
    Messages:
    492
    just for fun, rough up the contacts on the points a little bit and see if it cranks up. they'll still need to be replaced, but that's what's stopped me everytime i let something sit for a little while.
     
    gte636p, May 23, 2005
    #4
  5. May 24, 2005
    Dabblin

    Dabblin Barn fresh 67 cj5

    Joined:
    Jan 2, 2005
    Messages:
    63
    With the dist cap off, and the ign switch on, check for volts at the + terminal on the coil. If thats OK then use a screw driver to check the contact points. if closed then use a screwdriver to seperate them, a spark should jump the gap as they are spkit, or the screwdriver end will get the spark. If you have volts (12 or 6) at the coil but no spark at points then check to make sure the structure of the points assembly is not grounded, disconect the condenser, it may be shorted to ground.
    And last but not least was what happened to me. I had loosened the dist bolt getting ready to set timing, and lost spark. Turned out the dist was loosing its ground with the bolt loosened, no ground no point spark no go.
    Good luck.
     
    Dabblin, May 24, 2005
    #5
  6. May 24, 2005
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
    Joined:
    Nov 6, 2002
    Messages:
    4,275
    It's worth it to check the plugs also, since it doesn't really take too much cranking to foul them with fuel residue. I've used the wire wheel on the bench grinder to (gently) clean the tips of the plugs, and then put all but one plug back in and connect the wires. Connect the 4th plug wire to the loose plug and just lay the plug across the manifold, valve pan etc. to ground it, and have a friend crank it over. You should see a nice, fat blue spark on the tip of the plug. If not, you likely have points issues like the others have posted.

    Good luck, and let us know what you find!
     
    w3srl, May 24, 2005
    #6
  7. May 24, 2005
    kamel

    kamel Senior Curmudgeon

    Erlanger, Kentucky
    Joined:
    Jun 10, 2003
    Messages:
    891
    The theory of operation is that when the key is on there is 12 volts on the + side of the coil.

    when the distributor is turning the points are opening and closing.

    When the points close the - side of the of the coil is grounded, when they open the - side is not grounded.

    When the points OPEN the high voltage wire of the coil should generate a spark. When they close you should get a spark too, but the one that gets used to run the engine is the OPEN points spark.

    All the condenser does is to filter out the spike in the 12 volts dc so that the points don't get eaten up. If the condenser goes open then the points will last around 10 minutes or so before getting so pitted that they don't work. If the condenser shorts vehicle won't start. I have seen open condensers, but never a shorted one.

    Armed with that info you ought to turn the engine 'till the points are OPEN, and then you can simulate the process with wires and need not turn the engine over 'till you have found the problem..

    12 volts at + side of coil with ignition on?
    12 volts on - side of coil? If points are open it should be there if points are closed it'll be zero on - side of coil.
    short - side of coil to ground. Does it generate a spark from the high voltage lead of coil?

    With the - side of coil disconnected, measure continiuty from - wire to ground. Shoule be no continuity if points are open. Short points to ground and measure continuity of - wire to ground. Should have continuity.

    If you take time to understand the theory you can elaborate and design your own troubleshooting technique.

    After you go through it once you'll see it really isn't that tough.

    kamel
     
    kamel, May 24, 2005
    #7
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