Hi all, I had an eventful day yesterday and wanted to share the tale for the benefit of the forum.

TL;DR: the pink wire in the black coil connector was intermittently supplying the necessary switched 12v power the coil needed resulting in stalling, hard start, and subsequently no start conditions. Made jumper wire from fuse block to coil, car ran great.

Bought second hand MSD coil and 6A box with harness off member of another forum

Installed coil only first. Briefly started car up to ensure functionality, started and ran fine with MSD Coil, original 175k opti and ICM, went to bed.

Car started ran and drove fine until I was about 15 miles from home when it died during coast down to a stoplight, got it refired, died again short distance later. Much trouble getting it started again, seemed like classic ICM failure, ****s out once engine is warmed up (throwing no codes). Got the idea to disconnect MAF to put the car into OLSD/Limp Home mode. Started and idled like a champ...hmmmm.

Made it another 2 miles and died while making a U-turn to go home and not get stranded out on the road when I realized that I hadn't fixed anything by disconnecting MAF, would crank but not refire.

eventually had somebody pick me up and I went home to grab tools and parts store to get ICM because I was SURE that's what the problem was.

Swapped ICM, still no start, ****...Start going through the opti checklist with my multimeter. All 4 pins on ICM connector are doing what they're supposed to, all 3 on the coil connector are as well, I didn't think it was PCM because I was reading and flashing it, so I was starting to lose hope that it was maybe the opti and I was going to need a tow since I didn't feel comfortable doing that in a random roadside parking lot.

Decided to try to eliminate ALL doubt before wasting money on an opti I didn't need, like I had with the ICM. So I check the resistance of the new to me MSD coil, around 5K, good, OEM was like 8k when I checked it. Opti Harness resistance values were ~1-2.2k on all pins. I swapped the OEM coil back in just to be sure, no change....Its gotta be the opti...but it still didn't feel quite right as it was throwing no codes and I knew the injectors were firing while cranking because of the stroooong smell of gas from the intake.

So I ran through the checklist again and wouldn't you know it, the pink wire in the black coil connector (only wire in that connector on my car(95)) was now NOT showing 12v switched like it was when I went through the checklist the first time. It was not shorted to ground, and it had continuity with the #11 fuse (IGN) on the fuse block, but it was not transmitting power, at least not consistently. So my theory is that there was an incomplete/partial break in the copper in that wire, so I made a jumper to go directly from the fuse block to the coil to provide it the 12v switched that should have been on that wire, and the car started right up and I was able to drive home.


This was a failure that I haven't really seen before and maybe this info can help some people keep from throwing money at the problem with new optis, coils, and ICM's

 

That pink wire goes through connector C100 atop the passenger side wheel well near the pcm. It's pin G in the inset picture at the top right of the attached photo. That could be where the break is located.

 

Thank you for sharing that info, I hadn't gotten that far in the overall fixing of the issue to trace where that wire went. I was happy enough just to have it running again. I'll update the thread once I can do some more troubleshooting and see if I can figure out the root cause of what happened to that wire.