Victor,
I have a question for you. If I put a 5 volt pulse from
a triple 4050 into the coil trigger pin and it is clamped
to 2.5 volts is that an FET or a bipolar transistor base
in there?

Still trying to get a handle on these RX8 coil failures
to be sure I understand it.

Paul Lamar

A bipolar with the emitter grounded would limit the voltage to just
under 0.8 before failure.  My guess is the device is an Insulated-gate
FET with a separate zener clamp to prevent exceeding the allowed gate
voltage. put a series 1k resistor and see if the trigger still goes to
the same voltage. If so, the coil is clamped and you should not try to
force the trigger voltage higher, but should use a series resistor to
limit current from  the 5 volt drive.
Don't you have an RX-8? Can you put a scope on the trigger of a coil
with your car running?

Victor

Thanks Victor. Insulated-gate FET with a separate zener clamp to prevent exceeding the allowed gate voltage. If you insist on over driving
the zener probably over heats.

Yes I have an RX8 car. I'll do that on my RX8.

I tried the 1K resistor and it seems to help. A 2.5 K seemed to work better.

I have to get new coils first. Two parts companies have jacked me around
so far. Pep Boys and O'Reilly. Said they ordered them and they did
not come in. Price was $37 each. Looks like I'll try mail order from
Advanced Auto parts next. Cheapest price ($21)for the BWD E1001 so far.

I got some new info from the UK rotary club:
----------------------------------------------
Yes Clive, and we know the amount of so called failed engines being renewed in the early days when it was the coils causing poor starting/performance, sometimes the HT leads, and then on occasions the spark plugs....not an actual engine defect problem.

The RX-8 coil part numbers went from..
N3H1-18-100 2004-2006 (approx)
to
N3H1-18-100A 2006-2007 (approx)
to
The latest...
N3H1-18-100B 2008 on-wards (including 2009 RX-8's and R3's).

The N3H1-18-100B are the ones to use if you are replacing your coils, they will fit all years.

From what I have been told the outer black plastic insulator has different properties to prevent any shorting. Heat also being an issue, some guys have made heat sinks for under their coil packs.

--------------------------------------------------
These are Mazda part numbers. The internal insulation break down makes
sense as the longer you use them the re triggering increases. And then they
over heat.  This is probably aggravated either by a fouled plug or too big
of a spark gap. I am guessing.

Harley did you get your new coils? Do they look different?

Paul Lamar