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How to check ignition coil for power

Discussion in 'The Hokey Ass Message Board' started by 54LedSled, Nov 24, 2012.

  1. Delray
    Joined: Jul 14, 2009
    Posts: 46

    Delray
    Member

    If the points are closed you are grounding to the distributor so you would get a light.
     
  2. Delray
    Joined: Jul 14, 2009
    Posts: 46

    Delray
    Member

    Check if you have 12v or at least a light to the plus side of the coil when the engine is cranking. That car may have had two wires to the coil. One bypasses the resistor only when the engine cranks. The other through the resistor when the engine is running. It might be a long shot but it doesn't take long to check.
     
  3. George/Maine
    Joined: Jan 6, 2011
    Posts: 949

    George/Maine
    Member

    The one thing with voltage one or two strands of wire you can read volts.
    If you have old wireing the wire that goes to coil is also.
    Take the end and give a yank and see if it pulls out.
    Better yet put new wire from battery to pos terminal.
     
  4. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    Hey George thanks, my new 12v coil is internally resisted...so no need for external ballast resistor. Also, I checked for spark on my plug wire and nothing no spark, however my test light flickers on and off when the engine is turned over...so the points are getting power..basically I think I have a bad coil. Its brand new...but who knows...I'm going to try and replace it and see what happens...
     
  5. The condenser does NOT go to the + side of the coil, it normally attaches to the points wire that goes to the - side of the coil!
     
  6. Rob3865
    Joined: May 23, 2011
    Posts: 106

    Rob3865
    Member

    Take your shoes and socks off. Dump some water on the floor. Step into the water. Remove the coil wire from the distributor. Hold the metal end in one hand and ground yourself on the negative battery post with the other. Have someone spin the engine over. If you get knocked the hell out of, the coil is good.
     
  7. And normally it is inside the distributor, although some high performance condensors, due to their size and also possibly for heat reasons, were attached to the side of the dizzy (but that was usually a dual point, let's not get into that yet).
     
  8. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    I'm going to replace the coil with a new coil tonight and see if that does and wonders! Cross my fingers...
     
  9. Commish
    Joined: Jan 9, 2010
    Posts: 379

    Commish
    Member
    from NW Ok

    He will have to say, but he might have been referring to a coil mounted condenser mounted there for radio noise suppression.
     
  10. 54LedSled
    Joined: Mar 11, 2011
    Posts: 362

    54LedSled
    Member

    She's Alive!!!! She's Alive!! Turns out it was the coil....I kept thinking it was. I replaced it with a new and she fired right up. I set the timing and now she purrrrs like a kitten! Thanks again guys for all the help and information.
     
  11. When the points are closed the light will not come on. when the points are open the light will come on.
     
  12. bustingear
    Joined: Oct 29, 2002
    Posts: 2,283

    bustingear
    Member

    Putting air into a really old post and just experienced this with a flathead. Found that the points wire was touching the inside of the distributor where it moved through the housing. Cut a new square of rubber and reinsulated it and all is good. Just wanted to help the next guy with a possibility
     
    Truck64 likes this.
  13. Truck64
    Joined: Oct 18, 2015
    Posts: 5,325

    Truck64
    Member
    from Ioway

    One of the most useful troubleshooting tools is an inexpensive, simple ice pick 12 volt test light bulb w/ alligator clip. Points are simple but they can get crud on them, or wires short or ground out. No sparky no run.
     

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