So after replacing the optispark, I am getting the same problems I was having before. I've got a nasty sputter and the car stumbles and hesitates really bad when I mash the throttle. I have replaced the Opti, the coil, and now the module. However, with the new module, the car wouldn't even start, so I put the old one back and it started but ran like crap. I had the old module tested at two different placed and they both said it was bad. I had the new one tested and it was supposedly bad too. I have bought a third one and asked them to test it before I took it home and it failed too. I can understand one being bad out of the box but two! That seems a little rediculous. Has anybody else had this issue. I don't mind buying several different modules since I can return them as defective but I will eventually run out of options.

 

Rockauto shows the same ign ctrl mod for alot of vehicles. If the catalog is to be trusted, you can grab one from a mid-late 90's S10 or other vortec 4.3L which litter JYs

ACDELCO Part # D579 {#10482803} 4 PIN

 

Well I just installed the second brand new module and it doesn't even attempt to fire. But, when I put the old one back it starts. What the hell!!!

 

What do you guys think of the cts being bad? I know these won't set a code but they will cause havoc with the engine. This still doesn't explain why the car won't start with two supposed new modules.

 

Hook a scanner up and monitor the CTS in real-time. A bad CTS will have a fixed value

 

I got it figured out. After putting on a known good module and the car still not starting, I put the original back on the car and ran my scanner with the engine trying to run. All the numbers looked good so I was stumped. A buddy of mine let me borrow his MAF and that fixed the problem. I don't know why it never threw a code but now it idles like it should and has that beautiful crisp throttle response. I still don't know why three other control modules wouldn't even start the car but at least I got it figure out. I also noticed my left and right fuel trim it at 160 and I'm pretty sure it should be at 128. I am assuming this is becuase I put bigger injectors and haven't reprogrammed the computer yet. Does this sound right?

 

ok so i am thinking my ICM went bad. i went out to dinner with the wife and her friend, came out and cranks but i have no fuel to the tbi or spark. any suggestions?

 

I wouldn't think that the ICM would be causing the lack of fuel issue.