ignition wiring help

General Mopar Tech Discussions

  1. ksurfer2

    ksurfer2 Well-Known Member

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    OK, I'm stuck...mostly because of my lack of knowledge regarding anything related too electrical componets. My motor (73 440) was running an orange box with an electronic ignition (distributor with tan cap) prior to rebuild. After rebuild there is an MSD Ready-to-run distributor installed. I am still using the coil that was on the car previously. The MSD is wired to the coil as instructed, red to positive, orange to negative, and black to ground (I have it grounded to the firewall now, but have also tried the valley pan bolts and radiator mounting bolts). The coil has the same wires hooked to it as it did before the rebuild, one additional wire (blue) to the positive coil terminal and two additional wires (one green and one black/yellow) on the negative terminal. I have no idea if the color of the wires is correct as it was all wired before I bought the car. I am getting no spark. I am testing by hooking up my timing light as I turn the motor over and not getting any indication of spark. What am I missing. Do I need to run a different coil? Is there another piece to this ignition puzzle that I am missing? MSD directions do not indicate any other wiring other than what I have mentioned. Please help!
     
  2. beanhead

    beanhead Well-Known Member

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    Try removing the extra wires coming from the car. Hopefully somebody with more experience with these systems chimes in, but if I recall all you're supposed to need is a 12-volt feed from your ignition switch, the distributor does the rest and you appear to have that connected correctly. Disconnect the car wiring, put your voltmeter on each of those wires as you turn the key and see which one heats up when you turn the key on... Hook that one to your coil and see if she starts..
     
  3. beanhead

    beanhead Well-Known Member

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    Actually the more I think about it, those wires are likely coming from your Mopar ECU. You don't need that in the system so you will likely need to run a wire straight from where the ballast resistor ties in. MSD likes you to bypass the ballast resistor anyways..
     
  4. ksurfer2

    ksurfer2 Well-Known Member

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    To test, can I run a wire straight from the battery to the + terminal on the coil and attempt to start? If it fires, then find a circuit that is 12v with the key in on/run and tap into that directly to the coil? Please excuse if these are ignorant questions, i am modestly competent with things mechanical, but completely inept with anything electronic.
     
  5. BeepBeepRR

    BeepBeepRR Well-Known Member

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    Are you using a MSD 6AL box or just wiring it to the coil and Mopar box? If you are using just the RTR you do not need to use the old wiring other than the blue wire from the ballast resistor since its a keyed hot. That will go to the coil as noted in the first picture.

    Check this link out to see the old wiring and what you need to do now with the RTR MSD. https://www.chargerr.com/Ignition/Ignition.htm RTRNOBOX.png RTRwithBOX.png
     
  6. ksurfer2

    ksurfer2 Well-Known Member

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    Now wired like the top diagram, no MSD box.
     
  7. BeepBeepRR

    BeepBeepRR Well-Known Member

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    The red wire from the coil to the switch would = blue wire from the ballast resistor "Its your keyed hot" . You should still ground the neg side of the coil.
     
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    • ksurfer2

      ksurfer2 Well-Known Member

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      OK...reading that is like reading a foreign language. I am not sure what you are telling me. This is my electronics ignorance/incompetance showing. Are you saying that I need to find circuit from ignition switch and run directly to coil? Not sure what you are saying about ground the neg side of coil.
       
    • BeepBeepRR

      BeepBeepRR Well-Known Member

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      Picture 1 It shows a red wire coming from a switch to the positive side of the coil.

      Your old wiring coming from the ballast resistor on the firewall should have a dark blue wire coming off of it. That wire is your keyed hot. You do not need to run a new power wire to the coil. Find that wire and trace it to the distributor/coil area and you should hook it up to the positive side of the coil then get in the car and fire it off. Should run.
       
    • ksurfer2

      ksurfer2 Well-Known Member

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      This is where I am lost, I have no unconnected wires. I have looked thoroughly. Everything that was connected to the coil before tear down has been reconnected. I was careful to mark each wire that I disconnected to make sure things hooked up as before.
       
    • BeepBeepRR

      BeepBeepRR Well-Known Member

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      This picture here that you posted... This wire goes to the positive side of the coil. If you do not have a spade terminal I would go to autozone and buy one of these.

      1209c.jpg

      wire-1-jpg.jpg
       
    • ksurfer2

      ksurfer2 Well-Known Member

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      that wire was not connected to anything prior to teardown. It comes directly from the back of the alternator That is what has me most confused!
       
    • BeepBeepRR

      BeepBeepRR Well-Known Member

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      Can you take a picture of your coil wiring. the firewall wiring and how you have the distributor hooked up. You should not need the old Mopar box. And it can be taken out of the car.
       
    • beanhead

      beanhead Well-Known Member

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      BeepBeep is correct.. the black/yellow should be coming straight from your ECU, the green wire sounds like a tach wire to me do you have a tach? The blue wire will be coming from your start side of your ballast resistor so if the Mopar electronic conversion was done you need to get that ballast resistor out of there and simply connect together, the wires that are landed on each side of it this will send 12 volts to your coil when the key is in either start or run. Long story short, unhook the green (unless it's for a tach) unhook the black/yellow, and just for simplicity's sake unplug the harness from your Mopar Orange Box. It should start right up... You will want to go back and get the ballast resistor out of the circuit so that your coil can have 12 volts at all times but the engine should start and run with it in there, it just lowers voltage to your coil a little bit when the key is in 'run'..
       
    • ksurfer2

      ksurfer2 Well-Known Member

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      Yes, I have a tach. I will look in a few minutes and see if bypassing the ballast resistor solves the problem.
       
    • ksurfer2

      ksurfer2 Well-Known Member

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      OK...one side of the ballast resistor has a blue and a black/dark grey (solid color but can't tell in the horrible light) wire the other side has a blue and a light blue/yellow wire (wire is two colors light blue and yellow). Solution is as simple as connecting these two pairs of wires together? They are both in female blade connectors. Fashioning a connector to link the two female ends is all that is required?
       
    • BeepBeepRR

      BeepBeepRR Well-Known Member

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      I cant remember but it seems like I did bypass the ballast resistor by making a jumper. Try that and see if it works.
       
    • ksurfer2

      ksurfer2 Well-Known Member

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      Do all four wires get jumped together?
       
    • beanhead

      beanhead Well-Known Member

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      You can, but for the long term you may want to disconnect the existing mopar ECU wire(Just a note here....it can be beneficial if you drive a lot, to neatly tuck the old wires aside without removing them completely, in case the msd goes on the fritz you can just hook the mopar box back up to get you home..it's been known to happen:rolleyes:)
       
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      • ksurfer2

        ksurfer2 Well-Known Member

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        hooked up the jumper cable (see pic). No change. :-( thumbnail.jpg
         
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