I've been running FAST + Delteq + MSD DIS 4 using the opti only for the cam sensor for quite some time on a turbo car. Recently, it started missing, backfiring, and popping for no reason at idle (I won't drive it in this condition... too much invested)

I swapped a stock PCM back in just to see what kind of DTCs would show up. I got P1351 - ICM High Voltage as the only spark related DTC.

I pulled the Delteq off and put in a stock coil and ICM, ran opti spark plug wires and tried to fire it up. I heard sparking coming from the opti, like it was shorting to ground inside itself.

I decided to run a spark plug right off the coil wire. It sparked like mad when i cranked it over.

I hooked the coil wire back to the opti and turned off all the lights and had my wife crank the car over while I was both underneath and above the car and there was no visible spark, but I could still hear loud sparking from within or near the opti. It sounded like it was arcing to ground instead of following the path from rotor to cap and out through plug wires.

Anyone ever hear of something like that? I ordered a new opti and I'm hoping that is the problem. The one that's on there has less than 3k miles since new, never been in the rain, never had anything leak on it, and I've never even used the high voltage side of it...

 

I heard that very same noise yesterday and I kept looking for an arc coming from the coil. Ended up that sound was coming from within the opti and was the remaining piece of the rotor striking all of the pieces that broke off.