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  1. #1
    FEP Senior Member 86GTdriver's Avatar
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    May 2007
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    Norfolk, VA (again)
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    Default Ignition Coil Hot With Key Out of Ignition

    Been chasing an electrical gremlin today in this sunny 55 degree weather. I went out to start my '86GT, it cranked and turned over easily, but only ran about ten seconds before it died. That wasn't entirely surprising because I don't drive it often. It cranked over again easily and ran for about another ten seconds. After that I was getting fuel, starter was cranking, but no spark at the distributor. What was surprising though, and I've never seen this before, is the MSD Street Fire coil was very hot to the touch. At this point I wasn't trying to start the car anymore. It was so hot I had to pull the negative battery cable before it would cool off, so it seems it's being powered regardless of key position or perhaps it is internally shorted.

    Upon battery reconnection it started heating back up, so I disconnected again and pulled out the Hayes manual to page 12-33 and started looking. Seems to me if it's not the coil, I might have a bad ignition switch in the steering column. Since the pair of hot at all times input yellow wires that go to it, eventually go to the red/lght grn (negative side) output wire that goes to ignition coil, I guess it could be placing a load on the ignition coil that way, therefore is something internally short at the ignition switch at the column. Or, the dk grn/ylw wire from the the TFI module, also to the negative side of the ignition coil. So somehow there's a load being placed onto this coil, it's just not putting anything out to the dizzy even with said load at all times it seems.

    Even less likely, but think it's worth mentioning is possibly power from pin 4 or 60 from the ECC somehow.

    I replaced the plugs, wires, dizzy cap, dizzy button, starter solenoid and ignition coil about 20 months ago. I only drive the car about 20 miles a year and don't race it at all. Dizzy is OEM, PIP I believe is original, the TFI isn't, but it's been on there at least ten years. I have replaced the key cylinder and ignition switch in the column in the past about a decade ago as well. Haven't looked too closely at either though so far.

    Utterly confused as to where to even start with this one. Has anyone ran into this before?
    Last edited by 86GTdriver; 04-11-2023 at 05:42 PM.
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