Tibo

iTrader: (15)

I've spent several hours recently going over this and either I'm missing something obvious or MSD is incorrect. I currently use MS3 extra V3.57 with our stock configuration GM HEI 8 pin module with a single coil. My entire distributor is MSD (part number 8366 https://www.summitracing.com/parts/msd-8366) which uses a magnetic pickup coil part number 84665 ( for the pickup and control module assembly https://www.summitracing.com/parts/msd-84665?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-msd-ignition&gclid=CjwKCAiAsoviBRAoEiwATm8OYO63HVmCq0NdFL-n9dtpTRNhaX_C1GnTbh4QWARJmnncdpYI4FWDPhoCvRcQAvD_BwE) or just the pickup (part number 84661 https://www.summitracing.com/parts/msd-84661?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-msd-ignition&gclid=CjwKCAiAsoviBRAoEiwATm8OYLEbqAuTgXhdxik1OMiGzDotj3vqs_WQHElIzkJUCXShGwWvq6WVyhoC4xkQAvD_BwE).

According to every schematic and direction I have read be it factory GM or MegaManual it states that on the 8 pin GM HEI ignition control module (ICM) the "P" terminal is positive and the "N" terminal is negative. Polarity matters is what I've read several times but I've also read that polarity doesn't matter. If it doesn't matter, why label them P and N terminals. For reference, here is an old page but it has the schematics: http://www.msextra.com/doc/ms2extra/MS2-Extra_HEI.htm

If you read through the installation instructions for the MSD pickup coils (It states it the same in all the directions as I believe MSD uses the same magnetic pickup on virtually all of their distributors) It clearly states that the black wire with the orange stripe is positive and the black wire with an purple or violet stripe is negative. Here is a set of instructions to reference: https://www.jegs.com/InstallationIns.../121-84661.pdf

I've been experiencing very rapid ICM failure and noticed that on my MSD distributor the wires (per MSD's instructions) were attached incorrectly, the reverse of what you would think they would be. The orange strip wire goes to the negative terminal and the purple wire goes to the positive terminal. I swapped the terminals on the ICM and the car barely started and barely idled before sputtering to death.
I looked around some more and If you look at the pictures posted on Summit racings website for the pickup and control module assembly it shows the wires going to the "wrong" terminals of the ICM according to MSD's instructions. Yet my distributor was also wired this way and ran.... weird.
I swapped the wires back around and the car started but still exhibits the random misfiring. Anybody have insight on this?