Quote:
Originally Posted by Sun Tuned
Kenth was posting some rather old Delco Service Bulletins. Rather informative .
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The whole works was part of a .pdf hosted on the internet by FeidlerH (spelling?) but the link I had went dead years ago.
It came from a Delco service manual, with some notes taken at an HEI service training conference. Some of the notes he posted were hand-written. Eventually, I bought a copy of that HEI training manual on eBay.
Delco talked about problems at cranking speed. They didn't go into detail. Until someone proves different, I'm going with the hypothesis that it has to do with EMP from massive instantaneous current draw when the solenoid pops the drive into position against the ring gear, and first engages the starter motor For a split-second, until the starter motor begins turning, it's essentially a dead short on 4-gauge cables. Ever see a car with a shorted starter motor, when someone turns the key to "Crank"? There's so much current flow through the starter cables that they become electromagnets, they'll slap up against anything ferrous, including the block or sheetmetal of the inner fender. Same deal with engaging the motor, but the duration is fantastically short-duration. Battery cables aren't shielded. The windings of the pickup coil...pick it up. If the windings get an induced positive voltage, the module ignores it. If the windings get an induced negative voltage, the module triggers a spark. If that spark happens to travel to a rotor that points at a cylinder that has burnable mixture and the piston in the right (wrong?) position, you shatter the starter motor.
That covers the pickup coil windings. I have no idea at all about the ignition coil windings.
But what the hell do I know? I don't work in electronics. I didn't go to school for engineering. I used to fix cars. I'll update my hypothesis when someone gives me a better one, or when I get older and smarter.