Ok guys, Took my 1991 GSX stock coils down the road today and on the way back, I lost fire to #2 and 3 also my tach was jumping or losing signal all the way. Pulled it in the drive way to figure out was wrong and grab the harness side of the coil pack plug and power transistor and it stopped. So I am in need of finding my short right there. Does anyone have the pinouts for these 2 plugs so maybe I can trace the wire that supports firing on 2 and 3 and also tach signal?

this what you need?

Awesome thank you, now i can dig into it over the holidays.

Bet one of the transistors in the pack shorted across-same happened to me with losing two cylinders on the way home. Only thing is my tach wasn't affected.

Do the 12v and 1.5v battery with light bulb to test transistor continuity.

I had one transistor short across so it wouldn't collapse the current for the primary coil of 1 and 4 sparkplugs, plus it also took out that coil.

Replaced the module and coil and all is good. Got my stuff at Rockauto for a good price.

Good luck - !

-DSM

Did you permanently lose spark on those cylinders? I can wiggle the plug to the power transistor and it stops. By the look of the diagram above, I might have a short in the #4 pin wire on that plug as it goes to the tach and #2 and 3. I pulled the plug today and it was pretty dirty so I cleaned it off and gonna see if I have the same problem once it stops raining here.