run-on with MSD 6AL

Electrical and Ignition

  1. frederick_76

    frederick_76 Well-Known Member

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    Anyone run into engine run-on with MSD digital 6AL? The fix in the instructions say to wire in a duel ballest resistor (see link, page 8). Just did this on my set up and right now its workin.
    408, Mallory Unilite, MSD digital 6AL, MSD coil.
    **Different car than the one I was asking help with yester day**
    6425.pdf (holley.com)
     
  2. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    ^^Notice they are talking about the warning lamp for charging system in GM and Ford^^ Mopars of our era have no such. What you really needed to do is find out the "root cause" of the problem

    What kind of aftermarket wiring / accessories you have on the car? And what are you running for an alternator/ charging system?
     
  3. frederick_76

    frederick_76 Well-Known Member

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    stock charging system, only other wiring I have is the headlight relay from crack back and the MSD box.
     
  4. Scody21

    Scody21 Just send it

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    Sounds like there is a problem with the switched power running the MSD box. The box is wired
    Small red wire - on/off for MSD
    Large red and black wire for +/- from battery
    Gray wire - tach
    Violet / green - distributor pick up
    Orange / black - coil
    There is a few other wires.

    I have the on/off wire ran to a switch on the dash for the ignition. Or you could also put a in-line switch (two pole) in under the dash somewhere as a hidden kill / theft deterant switch.

    The best would be to chase the wires and find out why the switched power is not turning off the MSD.
     
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    • pishta

      pishta I know I'm right....

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      There should not be 12V on the small red wire after shutdown. That low amp 12V is the relay's electromagnet power that pulls the big amp heavy wire switch closed. See if you can watch it with a meter when you turn the key off without the dual ballast resistor crutch.
       
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      • str12-340

        str12-340 FABO Gold Member FABO Gold Member

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        why do you think your run on is related to the MSD box???
         
      • 67Dart273

        67Dart273 FABO Gold Member FABO Gold Member

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        I don't know why it couldn't be............there is very little if anything in a fairly stock Mopar system to cause feedback of that nature.
         
      • MOPAROFFICIAL

        MOPAROFFICIAL FABO Gold Member FABO Gold Member

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        No. I have no idea what you're talking about. Must be a electrical issue, grounds or maybe too much initial timing or you are running in the primaries.
         
      • kiwigtx

        kiwigtx Super Moderator Staff Member

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        Like a Ford I wired a few years ago, you may have to connect a diode inline with the ignition circuit.

        Worked on a Ford, so it may be the same for your One-wire Mopar issue. The installation of the diode is clearly shown in the MSD wiring diagrams. :)
         
      • 67Dart273

        67Dart273 FABO Gold Member FABO Gold Member

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        As I said earlier, in the MSD manual, they are referring to Ford/GM regulators with the warning lamp circuit. Mopars don't work that way.
         
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        • frederick_76

          frederick_76 Well-Known Member

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          Ill dig a bit deeper this week, see if i find some wiring that isnt right.
          Its odd to me that it helped, but most likely just a band aid to the real issue.
           
        • frederick_76

          frederick_76 Well-Known Member

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          Didn't start doing it till after i installed the MSD box.
           
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          • frederick_76

            frederick_76 Well-Known Member

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            int timing is at 15*. thats what they ran it on the dyno at.
             
          • 67Dart273

            67Dart273 FABO Gold Member FABO Gold Member

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            An easy way to isolate is to just disconnect the "small red" and "hot wire" it to a battery source to run, then pull it back off and see if it quits Bear in mind a box problem could be temp rated, or intermittent, or some other odd cause, so I'd try it a few times
             
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            • frederick_76

              frederick_76 Well-Known Member

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              Ok, so just remind me how I should have my stock ballast wires (and what ones) hoked into the MSD. The car is a 69 Valiant.
               
            • frederick_76

              frederick_76 Well-Known Member

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              Well I feel stupid.... It had to do with NOT PAYING ATTENTION! I had all 4 ballast wires hoked to the small red MSD box wire. I belive that was feeding the box voltage with the ignition turnd off.... Thanks everyone for making me take a good look at my wiring. please dont think different of me!!:mob:
               
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              • 67Dart273

                67Dart273 FABO Gold Member FABO Gold Member

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                If you have a factory breakerless ignition originally, there are 2 wires already jumpered together at the ballast. There is one wire went to the box which should be dead. There is a third wire that normally has a brown along with one other wire which go to the same connetor terminal. That one and either one of the two which are factory jumpered should be connected. That point or else the old coil+ wire goes to the small red
                 
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