Here’s what happened. I had a miss and found out it was the #6 plug wire (the header burned the plug boot/wire through the firesleeve) . So, I replaced all the rider’s side wires (the wires only had about 150miles on them). Started the car and it let off a hurrendous backfire. Checked the wires and discovered that I had a couple swapped (no big surprise). Fixed the wires tried to start it and got it to stumble.

Here’s what has been done. I checked the ignition and found that the ICM was fried. Had it checked at Advance to confirm. Replaced the ICM. Checked the signal coming from the PCM to pin B on the ICM and get 2.2VAC. Pins A and D have 12VDC like they should. I checked the coil with an ohmmeter it’s ok and even swapped the coil out with a working spare that I have. There is plenty of fire coming from the coil, I checked that last night. I pulled a plug and kept it connected to its wire and cranked. The plug will fire strong maybe once then the spark dies out quickly. If I keep cranking, the plug will fire strong every once and a while and then die. All electrical connections have been cleaned and are nice and shiny.

Anyone have any ideas as to what got fried????


Thanks all. Cheers!!

 

If the coil is good and you are getting weak spark out of the plugs, I want to say opti. Could still be something else, but sounds like the culprit, considering you had a stumble to begin with. And a little vehicle info couldn't hurt

 

Ok - 96Z, 54k, A4 3.42's, AFR heads, COMP cam , COMP Promag rockers, COMP hardened pushrods, new GM roller lifters, CSR electric H2O pump, Pacesetter LT's, Flowstopper cat back and a new opti.

I wonder if I managed to toast the opti cap??

 

Don't see how you could have fried it since it typically has 30K to 40K volts running through it normally.

If coil spark is consistent but plug spark is intermittent. Either wire(s), cap or rotor is to blame. Is the coil wire going to the opti seated properly at the opti?

I have heard of quite a few that had loose rotors on even new optis.