Exploding Coils

Discussion in 'Injection Tech' started by binderbound, Jul 16, 2015.


  1. binderbound

    binderbound High Wheeler

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    I built an electronic ignition set up about 4 months ago and its been literally blowing up coils. GM TBI coil, GM HEI 4 pin module, new relay (triggered by original coil wire) 10ga wire from battery to relay and then from relay to 12v side of coil. Duraspark pickup conversion in the holley distributor. Just like the write ups here. All of the parts are about 4 months old except the coils. They were original GM parts. All parts grounded to a large aluminum angle that its all mounted to. I'm just trying to figure out what could be causing the coil blow ups. Has anybody experienced this or have any insight?
     
  2. binderbound

    binderbound High Wheeler

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    2015-07-15 18.55.27.jpg 2015-07-15 18.55.41.jpg 2015-07-15 19.15.39.jpg
    you can see the black bits of the coil blowing itself out.
     
  3. Bill USN-1

    Bill USN-1 Moderator Staff Member Moderator

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    You may or may not have a problem. Back in my junkyard parts days I would throw back about 75% of the coils that I looked at due to signs of arcing and burning around the bottom of the main core. You could visibly see a different color in the plastic around it. The other thought is the input voltage at highway speeds and the resistance of the secondary circuit. Plug wires and plug gap. Do they match what the GM used? Excess load causes the coil to work harder and the module to work harder. Higher voltage is higher amps.

    If your 13.8 at idle what is it at highway speeds?
    Coils work by grounding the - terminal. That's what it means. Just like points simply close and complete the path to gnd so the coil fields charge. When the points open the field collapses and has no where to go except to the secondary winding and out the coil wire.
     
  4. binderbound

    binderbound High Wheeler

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    I put a new coil on and made sure the ground was perfect and even ran a secondary ground wire from the mounting plate to the battery ground. I also shortened up the coil wire. So far the couple days of test runs and drives have been good. I guess we'll see what happens.

    Thanks!
     

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