On ‎1‎/‎2‎/‎2020 at 10:21 AM, Captain Obvious said:

Dave, I haven't looked at the design of the ignition modules to see if they reference either side to chassis ground. My assumption is that neither side would be tied to hard to ground in the module. That assumption is based on the twisted-pair nature if the pickup wiring. They are trying to reduce the loop area with the twisted pair and it would completely defeat that purpose if they would tie one side to ground in multiple locations.

My assumption without any reverse engineering is that the pickup inputs are not galvanically isolated (with a transformer or something), but they may feed some sort of floating input differential amp at the input stage of the module. If that's the case, tying one side to ground might not cause it to malfunction, but it certainly isn't necessary or desired.

roger that. been working just fine since I disconnected that suspect added by PO ground.

I suspect that your PO thought "well, green is ground, right?"

Seems a bit of a leap, but that's all I got.