I'm just about finished putting together my COPs. At the moment I only have it grounded through the coil harness with a single 14gauge wire. Is this sufficient or are others adding additional grounds. If so where are you grounding it. I believe I also read in one of the threads (though I can't find it now) that the Cap should be placed as close to the COPs as possible. Am I remembering correctly or daydreaming?

 

I'm wiring up my COPs tonight after work. Besides the harness ground, I'm going to run an additional ground to the cylinder head like the OEM coils.

I still have to search on how to wire in the capacitor. I forget whether the long or short wire on the CAP does to the +.

EDIT: Found info on wiring capacitor here:
https://www.miataturbo.net/forum/t19939/

 

Both my cars are just grounded through the harness. No problems here.

 

I guess I'll just do that and add another ground if I need it later.

 

See the extra black wire... attached to engine grounding bolt near the end of the fuel rail. That's the way Brain did it in his original thread. It might not be needed, but the minimal effort makes it a no-brainer for the redundancy.