Just picked up a non running 94Z, was told there is no spark, happened before about 6 months ago and the opti was replaced, and then after 6 months lost spark again. Opti was a GM unit. Can an opti go bad that quickly? Is there any way I can confirm it is bad before replacing? Maybe a troubleshooting map with voltages to check for in and out of it? I would hate to replace it for nothing. Thanks!

 

Well.... Hard to tell but I put a new one in mine and then it went out like a week later. It took me months to figure out it was messed up again too. Come to find out My water pump was leaking and the opti got a bunch of water in it. So I guess it just all depends on what it's been through. I know this is not really helping you out though. Sorry.

 

thanks for the reply, I wondered about the water pump causing the fail, but I am not sure it is the opti yet.

 

I would unhook the coil wire from the opti and see if it is getting spark there. If it is then it is probably the opti if not then try your coil and control module.

 

Thanks, is the opti just a distributor of the spark from the coil or is there a module in it as well? Does the LT1 use a crank trigger or is there a module inside the opti? Just trying to understand how the spark system works on these cars, I am only familiar with points and conventional HEI systems.

 

The optispark is kinda like a cd player It has a wheel in it that has little slits in it and an optical eye that reads them. Basically is what happens is the cam has a pin coming out of it that hooks into the back of the opti, that spins the wheel, then the laser eye reads them, It isn't like any other distributor it's all controlled by the computer. If you look on the passenger side of your intake you will see the cable that runs to the front of the intake manifold and down into the top of the opti. Something like that anyway. I'm sure someone else can explain it better.

 

The opti has a reluctor ring in it. The cam spins the ring and a sensor reads this spinning ring and sends a High and low resolution pulse to the ECM. The ECM then tells the ICM to fire the coil. You need to make sure you are getting power to the opti. Check for corrosion on the opti harness plug. Make sure you have not damaged wiring. Then you can proceed to check for voltages on the ICM to see if the ECM is telling it to come on. I can not remember what they are off hand, but shoebox has some great troubleshooting stuff on his site. Here check out this link:
http://shbox.com/1/4th_gen_tech2.html#opti_test

 

Thanks!

 

http://www.mainstreamtopics.com/foru...p?showtopic=78

That will walk you through checking the Opti and other ignition components.