Perry Mick wrote:

I think Tracy says in his book that Mazda uses different timing
between leading and trailing plugs ( I may be wrong about this, 
haven't looked at the book for awhile) for emissions control
reasons.

However, when I look at the output of the Mazda ECU with an
oscilloscope, I see the leading and trailing pulses exactly in
sinc, at least at low rpm (<=2000).  

If someone has more info to suggest I may be wrong about this,
would like to know. The leading plugs fire twice as often in the
stock setup as the trailing plugs, both leading plugs fire       
simultaneously on front and back rotors.  I.E.: On one rotor the
leading and trailing fire simultaneously, on the other rotor,
the leading plug is also firing at the same time, very late in  
the expansion cycle.

Perry Mick

Perry I think your scope trigger is off.
I could be wrong. This may be a smog strategy.

PL
 
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