Deenasty

well I was working on my friends 94 z28, and it is having an ignition problem. There is no spark. I already tried swapping the ICM and Coil with mine that are working for sure, just for the hell of it. No spark still. I followed the instructions on shoebox's page. Both terminals A and D are getting proper voltage. When I test Terminal B while cranking, I get 0 voltage. This either means that the opti is not sending a signal to the PCM or the PCM is not sending a signal to the ICM. Is there a test I can run to make sure the opti is sending a signal to the PCM? Also if The PCM sends a signal to the ICM, and there is no voltage at the ICM, doesnt that mean the Opti is not sending a signal to the PCM? THanks guys!

slopokrodrigez

I don't mean to jump into Rob or Freds thread and with all due respect, but just wanted to be sure you set your meter to AC when checking the white wire on pin B of the ICM?

Have you checked the condition of the 4 pins at the opti, the connector about 2 feet from the opti and at the PCM? Also be sure to check between the pink/black wire and the red wire for 5 Volts DC with Key On Engine Off.

You could actually see the low res signal change if it's working with the meter set to DC and put one lead on the red/black wire and the other on the pink/black wire. With the plugs out, you would have to rotate the engine over by hand with the KOEO. Yeah I know, a lot of work but if it saves you some money and doesn't cost anything to do. You don't have anything to loose.

Thanks Rob and Fred.

Dave

Deenasty

no slopokrodrigez, with all respect the more feedback the better! I used the search feature earlier and you seemed to chime in on a lot of the ignition related problems, and you seem very knowledgable. Yea when I tested the white wire, my DVM was on AC scale, and recieved nothing upon cranking the motor..I have not checked the condition of the pins at the opti, or harness or pcm. I was going to pull the pcm an test the wire, and the pin on the back of the pcm. I know you mentioned it on one of the previous posts, but do you know what pin number the white wire is?

also to test the low res,(DC one lead on pink/black one on red/black) with the plugs out turn the motor by hand you mean? I dont know what "KOEO" means.

Basically, it is either a bad wire from the pcm to the icm, bad harness from opti to pcm, or bad opti correct? How can I check to see that the opti is working? Thanks everyone..

Injuneer

I'm getting to the point where I really recommend AGAINST calling out a specific person or persons to respond. I know Shoebox feels the same way. You are only hurting your chances of a knowledgable response. It shows a disrespect for the opinions and help you would get from other people who are here and help out all the time.

Deenasty

I never meant to disrespect or down anyones opinion's or knowledge. In fact this post was never intended for ONLY you of shoebox. But I can see how it can be taken like that after the title of the thread states it. I simply meant that if any of you two had the time, to please chime in because both are extremely knowledgable and have helped me out a ton in the past. I apologize if the title threw people off. That was never my intention.

mhhodges76

I'm having a very similiar problem. The car is in the shop as we speak. I'll keep you updated if I find out anything helpful.
Matt

Deenasty

thanks a lot...ttt

slopokrodrigez

Yeah I didn't explain to turn it over by hand good enough with a breaker bar. I would ohm all the wires first if you have any voltage issues. The white wire goes to black connector of the PCM on pin 5. You will see the white wire there. Check all the voltages like Shoe or I had stated first. If they aren't there, like the white wire, then start ohming them.

KOEO is key on engine off. Sorry.

Dave