Victor,

I am down to my last three workable RX8 coils and
one of those might be dead.

Here is the schematic on the GM coils.
Why do you think they ran a separate signal ground.


Paul Lamar

The GM coils do the same thing. Retrigger with as much as
2.2 K in series. However they only limit the in put trigger
to 5 volts from five. The schematic calls out a .05 uf across
the trigger line. That seems to help.

It also seems to be highly configuration sensitive.

By that I mean how the wires are placed.

Perhaps the close proximity to the spark is feeding
back to the trigger. In the car there would be
a short piece of spark plug wire to the spark plug.

In any event the GM coils seems to be more robust but they
don't like a dwell time less than 5 milli seconds.

I'll get some spark plugs wires and move the spark away
from the trigger input.

I also moved the battery and the coil a couple of feet away
and shielded the trigger wire. All this changes things.

IMHO coils should not have electronics in them.
MSD ignitions do not do that.

Paul Lamar