I was driving the other day when I went to turn off my 1974 Mercury Comet that I have been restoring, and I took the keys out and it kept running. I popped the hood and took off the center High Tension Lead connected to the distributor and it turned off. I went to start it again, and it would not start. I assumed it was a bad ignition switch, but I came back to the Comet about an hour and a half later and it was smoking under the hood. My ignition coil had exploded like a battery and started overloading wires from my wire harness. The red-green wire going from the coil to the starter solenoid burned taking the red-blue wire with it (the insulation was fused together, but only the red-green wire was consistently burned) Someone had previously messed with these wires, because there were previous splices, but no complete replacements. This is my first project car and I have been trying to rewire the wiring harness of the wires that were burned. I re-ran the red-blue wire going through the firewall (nothing went through the firewall or touched the interior) and I reran a Red-green wire going from starter solenoid to a newly installed (post wire burn) ballast resistor which the starter solenoid and ignition coil are wired to one side and the ignition switch is wired to the other. I have wired everything according to this wiring diagram from a Mercury Comet/Ford Maverick Chiltons manual imaged below. The engine will crank but not fire. I do not seem to be getting spark from the coil into the distributor. I have cleaned all my connections as I went and I am getting no change. I have not replaced the fuse under the dash as shown on a wiring diagram from maverickcomet.com and I used a ballast resistor instead of a wire, but other than that, the wire is good and clean, my multimeter show voltage from everything except the secondary ignition coil. I am unsure if these may be the problems but I cannot seem to find similar issues. I believe there should have been sacrificial wire, relay, or fuse if something like this were to happen, but the previous re-wire may have screwed me a little bit, haha. I do plan to eventually put all of that back in. Nothing a bit of elbow grease cant fix. Any help and advice would be appreciated. I may be slow to respond because of a busy life schedule, but eventually I will show pictures of the mock-up I have. Thank you, all.
The coil overheated because the ignition switch was still supplying power when in off position. OR the ignition relay inside the starter solenoid stuck, continually supplying voltage to coil. Either condition can also overheat wiring. Closed points grounds negative side of coil causing no start and again coil overheat. Shorted wiring on negative side of coil also causes same condition.
