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Thread: MSD 6520 - No Spark

  1. #1

    Default MSD 6520 - No Spark

    I have an MSD 6520 running the 427 in my '68 corvette, it was running great last time I drove the car, but when I tried to start the car a few days later, it wouldn't fire. The red LED light on the box is coming on and blinks rapidly when cranking, so it has power and is getting signal from the distributor, just isn't putting any power to the coil. Any suggestions before I junk the box and have to buy new ignition?

  2. #2
    Join Date
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    And you have proved you have no spark at the plug leads? What carburetor do you have? Gary
    Regards, Gary

  3. #3

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    I've verified no power to the coil, no spark out of coil (by bridging wires as stated in manual), and no spark at plugs. Carb is a Holley Demon.

  4. #4
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    How did you test for no power to the coil, considering it's CDI, near 500 volts? Unless you read it with an oscilloscope? And what coil are you using?

    From Page 10 of your 6520 instruction set:
    5. With a small jumper wire, short the MSD’s Green and Violet magnetic pickup wires together
    several times. Each time you break this short, a spark should jump from the coil wire to
    ground. If spark is present, the ignition is working properly.
    If there is no spark skip to step 6 below:
    6. If there is no spark:
    A. Inspect all of the wiring.
    B. Substitute another coil and repeat the test. If there is now spark, the coil is at fault.
    C. If there is still no spark, check to make sure there are 12 volts on the small Red wire
    from the MSD when the key is in the On position. If 12 volts are not present, find another
    switched 12 volt source and repeat the test.
    D. If, after following the test procedures and inspecting all of the wiring, there is still no
    spark, the MSD Ignition is in need of repair. See the Warranty and Service section for
    information.
    Last edited by Gaz64; 11-10-2019 at 07:04 PM.
    Regards, Gary

  5. #5

    Default

    Right on the money!
    shake-n-bake

  6. #6

    Default

    I've followed the test procedures and still have no spark. So I guess my unit is dead. Shame. Thanks for the advice.

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