I have been fighting a high idle and surging problem for months now. I have checked the codes before and all went well, but now I'm not getting code 12.

With a jumper in A and B I turn the key to "ON" and the check engine light quickly flashes once and then comes on solid. There doesnt seem to be a pause between the flash and solid light. If I turn the key off and then on again I often get just a solid light that comes on with no flash. If I remove the jumper from A,B and turn the key to "ON" I get teh exact same results.

I even tried disconnecting the MAF wile the car was running so that I knew there was a code. When I disconnect it the check engine light comes on, but I still cant get any codes out of it.

 

normally, a lack of code 12 means your PROM or ECM is junked...

 

Doesnt the check engine light stay lit no mater what even when the car is running with no a,b jumper when the ecm is bad?

Doesnt the code 12 mean no distributor motion or something like that? There was a post with what all the codes meant somewhere on here that said that. If that is true could maby the wire that tells the ecm this is damaged?

 

with no jumper, the light should just come on and stay on with the key in the on position with the motor not running.

and code 12 DOES mean no reference pulses. if the wire in the ALDL port is bad or the terminal is loose/damaged, it could cause the ECM to not go into this mode.

 

Would this wire happen to be the same tan/brown wire that you disconnect in order to set the timing? I just messed with that wire.

What I was trying to say about the key on and no jumper was, it would some times flash once then light solid other times it will just light solid. Basically exactly what it does with the jumper.

 

that would be the bypass wire... goes to pin D5 on the ECM.

the reference wire is purple/white stripe and goes to pin B5.

 

Okay, well I traced the wire out and it looks fine. I also tried swapping the superchips prom out with the factory and that didnt fix it.

Is there some other way I can confirm that the ECM is indeed bad? Could this also have been causing my idle problems all along, and the ECM has finally just gotten to the point that I cant even pull codes?

 

a bad ECM can cause all kinds of crap to happen...

if it's all the way gone, none of the outputs should function(TCC lockup, EGR, AIR, probably the cooling fan as well).

 

The fans come on when the car is first started but no longer come on when checking codes like they should. I also dont think im getting TCC lockup. I guess I should probably start looking for a new ECM....

Thanks for all the help by the way.

 

no problem. if the problem is still occuring, i would say you may be looking at some harness damage or some other condition preventing the ECM from operating properly.

 

I cant seem to find another ecm. I have a ecm with the SN: 1227165 and I cant seem to find one with that number. Will one out of a 5.0l fit as long as I put my prom in it?

The car is a 1989 Iroc-z camaro 5.7L TPI.

 

any 86-89 5.0 or 5.7TPI ECM should be a 1227165, so yes.