I have a miata with a 1995 single turbo rotary engine. It is running with a wolf3d, msd 6a, 3rd gen coils, and TII ignitors. There are sparks on the trailing plugs, but no spark on the leading plugs. How do I determine if the leading ignitor is bad or if the msd6a is bad? I put a voltmeter on the trailing coils and got 12.9 volts. I'm not getting any voltage on the leading coil.

 

most who run an electronic spark amplifier box have it only connected to the leading coil. if you motor is so wired it is likely there is something wrong w the msd or with it's wiring. remove the msd and wire your leading coil in normal mazda fashion. your car should run. you should also check the lead coils for continuity but that doesn't sound like your problem as you don't have voltage.
good luck,
howard coleman

 

thanks, howard. i replaced the msd6a and the car fired fired right up with all coils working. i have a hks twin power and a msd dis-2 unit from my previous cars and i'm wonding if it would be benificial to put in either one of those for the traing coils.

 

no benefit unless you are making in excess of 500 flywheel hp.
i am glad you got it running.
howard coleman