Quote Originally Posted by Sook View Post
Factory wiring harness was replaced with a Howell EFI engine harness.
http://howellefi.com/general-motors/...e-1993-camaro/

Swapped the alternator wiring around to Pranav style, car is charging, DC bus is still a bit noisy, and I'm still getting erratic tach. No idea if it's better or worse. One thing I do notice is that it looks like the alternator is kicking on and off, going between 12 and 14 volts occasionally. Usually always 14, but it dips for seconds at a time. I guess S is a sense line, looping back to the alternator output. Not having to futz with a resistor is nice.

The coil has been swapped twice, the one that was on the car when I initially tried to start it seemed to have a damaged connector. The second on was swapped when trying to diagnose the initial ICM failure. Third one still on the car.

I'm not comfortable saying the sky is blue, much less what's killing the ICM. I'll probably do a cooling mod as well - still no smoking gun on what's killing them.

- Josh
With the 470 ohm resister between your sense and your sorce. Your alternator should put out steady it should not fluctuate. Also if you have a bad ground your alternator will not put out correctly. Did I say check your ground? :-)