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  • zero spark to the coil

    Hi all, I'm in the process of firing the 58 back up again and for some reason I'm getting zero spark to the coil.
    I've triple checked all distributor wires to and from the ballast resister and everything is where it should be.
    I've tested by running a plug straight from the coil lead and earthed it with no luck.
    This system was brand new and did work previously.
    Is there anyway to check with a test light or something to see what's going on.
    It's a Mallory system and I'm not sure what else to check.
    Cheers Chris.

  • #2
    Maybe your terminology is just wrong but you should be getting spark FROM the coil not TO the coil. Try running a wire directly from the battery + to the coil + and see if it starts. You should have 12V at startup coming directly from the solenoid. The ballast resistor only comes into play after it starts and the key goes back to the ON position. You need a test light or volt meter to tell for sure. You can make a simple test light using wire and a 12V bulb.

    John
    John Pizzi - Squarebirds Administrator

    Thunderbird Registry #36223
    jopizz@verizon.net 856-779-9695

    http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

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    • #3
      If you have a meter here is a decent write-up on how to test the coil.

      http://autorepair.about.com/od/troub...-ohm.htm#step1

      Primary resistance should be in the 1.5 ohm range and secondary resistance should be around 8000 ohms.

      Another method if you don't have a meter - basically a visual of what John is describing ( brought to you by Mr Rogers )
      https://youtu.be/rJYJ3KvPhhY


      Eric

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      • #4
        Chris, I know you hate electrical problems but you need to get into this. BTW is this a Mallory Unilite module in stock distributor?
        Here's the business end of all spark:

        Notice the two posts are labeled (Battery) + and (Dizzy) -.

        I'm going to repeat John's advice: Use a jumper wire from your battery to the 'B' coil terminal. Turn the key to start the car. As long as your jumper is there the engine will continue to run. This is a test so don't leave your jumper on more than fifteen minutes because the coil will get too warm.

        If the car starts, your wires from the ignition switch (including the ballast resistance) are open somewhere. In this case, pull your jumper off and use a 12-volt test light to find the 'open'. With the key on (not 'start') your coil should show +12, with your light on ground and the other prod on the coil (+). If not, keep the light on ground and move the other prod to your ballast resistor. Check both sides. If nothing, keep going back to your Key switch.

        Eventually, the light will shine. 'Looks' mean nothing. It's possible that any connection can be loose. The key switch is fed from the headlight switch. I've found broken and loose connections between the two.

        I make my own test lights using a simple dash bulb (like a #57) with two small but long wires soldered to the bulb and wrapped in black tape. You can get fancy and install alligator clips to the ends. Store bought LED and neon test lights simply do not tell the truth. Incandescent bulbs do because they actually put a load on the circuit. This should find any loose connection or broken wire.

        If you have voltage at the coil + and it still won't fire, check the coil's minus side to ground with your light. If it pulses when the starter is running, you probably have a bad coil. it's rare but possible. Try using a different temporary coil. - Dave
        My latest project:
        CLICK HERE to see my custom hydraulic roller 390 FE build.

        "We've got to pause and ask ourselves: How much clean air do we need?"
        --Lee Iacocca

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        • #5
          Thanks guys, yes John that's what I meant, there's no spark coming from the coil and I've checked the coil positive with a test light and it seems I've got no power coming from the 12v ignition wire.
          Haha Dave, your getting to know me to well, I really hate electrical problems.
          What I am wondering now is weather the problem I had the other day with the lower dash steel trim arcing on the circuit breakers has burnt something out.
          I have all lights and accessories but my clock stopped working immediately after that happened so there could be more to it.
          My ignition system is all Mallory promaster as I've got the Windsor in there now, all brand new and was operating perfectly when I did all the test running before removing for paint.
          Cheers guys, looks like I'm spending an afternoon under the dash again, my favorite job haha.

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          • #6
            I have an MSD distributor, and the magnetic pickup in the bottom of it just decided to die earlier this year.

            No spark.

            Replaced it for 30 bucks and I was back in business again.
            http://www.tbirdregistry.com/viewdat...ryNumber=33517

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            • #7
              If you examine the wiring diagram you may notice that the ignition circuit has NO fuses or circuit breakers. This was engineered as such so that a stupid fuse cannot prevent you from getting off the railroad tracks. Ford would rather burn up a wire before interrupting your ignition.

              If those added circuit breakers have long posts, trim them down and keep them far away from the body metal. Again, check the connections for tightness. Sometimes I use split ring lock washers. Even if the nut comes loose the lock washer is a spring that helps keep the connection tight. - Dave
              My latest project:
              CLICK HERE to see my custom hydraulic roller 390 FE build.

              "We've got to pause and ask ourselves: How much clean air do we need?"
              --Lee Iacocca

              Comment


              • #8
                Ok, I've checked the hot wire (red wire with green tracer) at the ignition switch and nothing, completely dead.
                What are my options from here, bear in mind I'm in Australia so parts are pretty scarce.
                Thanks Chris.

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                • #9
                  Is that with the key in the ON position. That's the only time that wire has power.

                  John
                  John Pizzi - Squarebirds Administrator

                  Thunderbird Registry #36223
                  jopizz@verizon.net 856-779-9695

                  http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

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                  • #10
                    Yeah it is, even tried cranking the engine to make sure and nothing.
                    Is it just a matter of removing and replacing or could it be another issue somewhere else.

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                    • #11
                      The red/green wire to the coil resistor only has power in the ON position. It does not have power when you turn the key to START. If there's no power in the ON position then your ignition switch is defective. You can move it to the ACC terminal on the back of the ignition switch and try it there. However your car should fire without power to the red/green wire. In START mode it gets power directly from the solenoid. If the car is cranking then you have power at the solenoid. Check the brown wire on the solenoid for 12V. That goes to your coil.

                      John
                      John Pizzi - Squarebirds Administrator

                      Thunderbird Registry #36223
                      jopizz@verizon.net 856-779-9695

                      http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

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                      • #12
                        Will it do any damage if connected to the acc terminal, I've definitely got power there.
                        The car cranks over perfectly.
                        Is the accessories terminal the one on the bottom from looking under the dash.
                        I haven't figured out how to get the switch out yet.

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                        • #13
                          The only reason there is a separate ON and ACC terminal is so there's no power to the coil if you just want to turn it to ACC to turn on the radio or something else. With the key in the ON position there's power to both terminals so it really doesn't matter where your red/green coil wire is at that point. There should be at least three wires on the ACC terminal. One of them is orange/yellow so it should be obvious.

                          John
                          John Pizzi - Squarebirds Administrator

                          Thunderbird Registry #36223
                          jopizz@verizon.net 856-779-9695

                          http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

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                          • #14
                            Ok cool, that makes sense.
                            Yep I've found the orange/yellow wire, along with 6 other wires on that terminal.
                            Now what's confusing is I've got 2 red/green wires, one is on its own in the center of the switch, the other is joined to 2 black wires on an outer terminal.
                            The center one is the one with no power, the one joined to the black wires has power.
                            According to my drawing the stand alone wire is the neutral safety switch.

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                            • #15
                              The neutral switch wire is red/blue. That should be on the center terminal. That only has power in the START position. That has to have power or your car would not crank. It sounds to me like you have power on the correct wires at the ignition switch. Did you try running a wire from the battery to the coil as I suggested. If that does not work then your coil is most likely bad.

                              John
                              John Pizzi - Squarebirds Administrator

                              Thunderbird Registry #36223
                              jopizz@verizon.net 856-779-9695

                              http://www.squarebirds.org/picture_gallery/TechnicalResourceLibrary/trl.htm

                              Comment

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