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Thread: Electronic ignition question

  1. #1
    Join Date
    Sep 2009
    Location
    Houma, LA
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    5,840

    Default Electronic ignition question

    Chasing a problem I've been having with my 1969 roadrunner. The previous owner had converted to the mopar performance electronic ignition. The car runs, idles, and drives fine. The problem I'm having is on start up, it won't spark unless the key is in the run position. In other words, turn it over and as soon as you let off the key it starts. I've changed both the ignition switch and starter relay.

    I'm fixing to trace all the wiring, just hoping someone here may have some insight before I get in too deep and it end up being a simple fix.

    let me try, im a genius

  2. #2
    Join Date
    Jan 2010
    Location
    Toms River, NJ.
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    2,254

    Default

    Maybe it was a homemade anti theft idea?

  3. #3
    Join Date
    Sep 2009
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    Houma, LA
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    Default

    Quote Originally Posted by 67charger View Post
    Maybe it was a homemade anti theft idea?
    Lol that would be believable if the wiring weren't such a birds nest.

    let me try, im a genius

  4. #4
    Join Date
    Sep 2009
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    Houma, LA
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    Default

    I think I've narrowed it down to the bulkhead plug on the firewall being the problem. The more we played with it the more often the car seemed to start normal. And all the wires and connections seemed right.

    I'm going to order a new under hood harness and re do it all in hopes to not only make it look cleaner, but to solve the problem. My next project is a motor build for the car so I want any other bugs taken care of before hand.

    let me try, im a genius

  5. #5
    Join Date
    Feb 2009
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    1,549

    Default

    Brown wire at the ballast resistor is your problem child. Crank power to coil.. Blue is run power to coil and goes thru ballast while it's running, to be reduced to about 8volts as the ballast heats up.

    To save future headaches. Change as much of the wire harnesses as you can. As soon as you can.
    They are 40+yrs old and stupid issues like this are very common.
    When you stop playing in the kiddie pool
    SharaDon Performance

  6. #6
    Join Date
    Sep 2009
    Location
    Houma, LA
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    Default

    Quote Originally Posted by SharaDon View Post
    Brown wire at the ballast resistor is your problem child. Crank power to coil.. Blue is run power to coil and goes thru ballast while it's running, to be reduced to about 8volts as the ballast heats up.

    To save future headaches. Change as much of the wire harnesses as you can. As soon as you can.
    They are 40+yrs old and stupid issues like this are very common.
    Yea that's what I found. Everything is wired correctly, brown wire tested good and circuits all functioned correctly. But like I said unplugging the connector at the firewall and messing with it seemed to affect the likeliness of it starting correctly. Not only are the wires old and brittle, but like I said the previous "mechanic" left some to be desired which made it a pain to work with. It's getting a new underhood harness and ill start from scratch.

    let me try, im a genius

  7. #7
    Join Date
    Apr 2011
    Location
    Indiana, USA
    Posts
    365

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    Nothing wrong with that. I know I went through my wiring several times before I found all the other wanna-be electricians that have touched the car in the past 40 years. (Uh, solid core Romex under the seats...Really?)

  8. #8
    Join Date
    Sep 2009
    Location
    Houma, LA
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    Default

    Replaced the underhood wiring harness with one specific for MP ignition and it works flawless. Back to cruising

    let me try, im a genius

  9. #9
    Join Date
    Mar 2009
    Location
    Waco, TX
    Posts
    3,237

    Default

    Sweet. Where the pics

    Sent from my DROID RAZR

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