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


Paul

On 12/29/10 you posted Part 3 on using the Denso GM coil and had run it
up to
12,000 rpm and showed a spark plug at 9,000. How does this jive with the
latest
concern that it takes 5ms to charge these coils, which corresponds to 7,500,
yet the coils apparently work well at 9,000?

Dan F



I did not have the scope on the trigger wire so it was probably self
triggering at some lower frequency. I was just looking at the dial of the signal
generator. They will do that. They will sit there and spark on thier own
until they die. It does this at dwell time frequency. In the case of the
GM 5 millisecond period. If I had let it cook longer it would probably have
committed suicide. :)

It had me fooled :)

Paul Lamar