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Technical Early Hemi Power to Coil but No Spark?

Discussion in 'The Hokey Ass Message Board' started by tartar_sammich, Jul 12, 2018.

  1. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,988

    porknbeaner
    Member

    Electrical parts being new does not make them good. It just means that they are new.

    I would a have suspected that the coil took a dump until you said it is electronic. Now you have way more places to have a problem. Now you have to suspect the control mod as well. I would suggest dropping in another distributer which would be easiest but I imagine that you don't have one at your disposal. You may do a google search and see if there is a way to check the control mode.
     
  2. Wow I didn’t even notice that. I have no clue.


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  3. I did drop in another distributor, this one is new as of yesterday. New module as well.


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  4. saltflats
    Joined: Aug 14, 2007
    Posts: 9,346

    saltflats
    Member
    from Missouri

    If the good ground to the distributor didn't fix it, I would be looking at the distributor.
     
  5. Ok. I just got off work and headed to the gym, when I get back I’ll try the ground to the distributor.
     
  6. Just tried the ground wire. No luck still. Also took a spark plug out and held it against a ground, no spark whatsoever. I just don’t understand how the problem could be the distributor. It’s brand new, and I feel that the likelihood of having one go bad and getting one that is bad straight from the factory to replace it is extremely low. Is there a way I can test the module in the distributor?


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    Last edited: Jul 13, 2018
  7. saltflats
    Joined: Aug 14, 2007
    Posts: 9,346

    saltflats
    Member
    from Missouri

    Did you ever try a different battery?
    Or the extra spark in the coil test?
     
  8. Haven’t tried a different battery, but that battery strong and is spinning the starter fine. Still have 12.75 volts to both sides of the coil. What is the extra spark in the coil test?


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    Last edited: Jul 13, 2018
  9. saltflats
    Joined: Aug 14, 2007
    Posts: 9,346

    saltflats
    Member
    from Missouri

    The one I seen in your video.
     
  10. Ah. I did the test again with Dad out there, the first time the coil wire shocked me when I placed it against the ground, and after that I held it with a pair of pliers. I didn’t see the extra spark again, but the spark was still weak and difficult to produce with the coil wire end against the distributor housing.


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  11. saltflats
    Joined: Aug 14, 2007
    Posts: 9,346

    saltflats
    Member
    from Missouri

    That sounds like a bad ground somewhere.
    It is trying to use you for the ground.
     
  12. Could it have been because the jumper wire wasn't getting a good ground?
     
  13. saltflats
    Joined: Aug 14, 2007
    Posts: 9,346

    saltflats
    Member
    from Missouri

    Yes a bad ground somewhere.
     
  14. Just wondering, because last night when I did it I held it by the boot of the coil wire and did it several times (trying several different grounds) and never got zapped, but this time I held it by the main part of the wire (don't know why) and it shocked me immediately. I'm just trying to think of where a bad ground could be. Before I tested the coil again, I moved the engine ground from the header to the starter bolt where there is bare metal, ground the frame clean of powder coat where the battery and engine grounds are bolted, and grounded the distributor. Any ideas?
     
  15. With the stray sparks in your video and you getting shocked holding the wire it sounds to me like you may have bad plug wires. Two weeks ago I had to replace the distributor cap on our 392 Hemi due to a cross fire light show it was putting on. It was also a brand new part from Joe Hunt, with a total of 20 minutes of run time before failing for no apparent reason. Lesson learned, even new parts can be shit.
     
  16. That's an interesting thought. Until I get the time to make new ones, is there any better test that I can do to determine if that is the problem?
     
  17. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,137

    sunbeam
    Member

    Light should blink when cranking Next question is test light on or off when touching neg side of coil? Thy removing wire from neg side of coil and arc it to ground with a jumper you should get a spark from secondary side of the coil every time the jumper breaks contact to ground. If you do get spark the petronix went south.
     
  18. kevin31
    Joined: Oct 1, 2011
    Posts: 35

    kevin31
    Member
    from ottawa

    Check to make sure your air gap isn’t too large at the pickup, too large a gap will give intermittent spark depending on temperature . Just cause it’s new doesn’t mean it’s right


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  19. Truck64
    Joined: Oct 18, 2015
    Posts: 3,264

    Truck64
    Member
    from Ioway

    There is arcing to ground elsewhere in that video. I'm no expert, but that also looks to be a pretty lame spark at the terminal. It should be shooting a fat long spark.
     
  20. So you’re saying I should get a spark from the jumper wire whenever it breaks contact with the ground? And if it does spark then the Pertronix is bad? And no, the test light doesn’t blink when touched to the negative side of the coil while cranking the engine. Same thing was happening even before I replaced the coil and distributor.


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  21. You’re right, the spark is lame and it was also really hard to produce. In the video, it looks like a spark is coming out of the plug wires, but the coil wire wasn’t connected to the distributor cap, so where could it have come from?


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  22. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,618

    Ebbsspeed
    ALLIANCE MEMBER

    Put your test light across the two terminals of the coil. As you;ve mentioned previously, you should see it pulsing. If it isn't then your problem is on the distributor side of the coil. Do you have an old distributor with points available to test with? Makes troubleshooting much easier, and will confirm where your issue is.
     
  23. Do I clamp it to one side and touch it to the other? The middle terminal prevents me from laying the light across both terminals. I don’t have a distributor with points in it, unfortunately.


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  24. Take the cap and get the distributor in the right position* and twist the rotor back and forth over the range of motion of the mechanical advance and see if that makes the coil spark.

    *I don't know how the positioning works with the Pertronix, or if it even works, as I have only done this test with normal distributors; but it stands to reason it should work the same.
     
  25. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,137

    sunbeam
    Member

    For a coil to work electricity flows through the primary windings with the points closed creating a magnetic field in the coil, points open flow stops and field collapse through the secondary windings producing a high voltage spark. The module is just a solid state way acting like points.
     
  26. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,618

    Ebbsspeed
    ALLIANCE MEMBER

    Yes, not sure what kind of a test lamp you have, but you need to have one side of it on the ignition switch side of the coil, and the other on the distributor side. No need to connect anything to the center tower terminal.
     
  27. It’s a test light with a ground clamp and the bulb is built into the handle, kind of like a screwdriver and you touch the pointy end to whatever you’re testing. So I guess I’ll clamp the ground of the test light to the - side of the coil and touch the positive side with the test light, and see if it blinks?


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  28. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,618

    Ebbsspeed
    ALLIANCE MEMBER

    Yep, that's the way to do it.
     
  29. Just did it like that on the ‘37, light was dead. Tried it on our ‘65 F250 with an MSD electronic distributor and Blaster Coil and saw pulsing.


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