Idle Quality Issue

[cadillac531]

Originally Posted by A26B

Spark plug gap was revised from 0.035 to 0.050, just to improve idle.

I didn't change them to the .050, I still have them gapped at .035.

[tccrab]

Any ECM from any year ZR1 will work in any year ZR1.
The PROM or MEMCAL chip is year specific.

Crabs

[cadillac531]

Originally Posted by tccrab

Any ECM from any year ZR1 will work in any year ZR1.
The PROM or MEMCAL chip is year specific.

Crabs

OK, Great. That's what I thought, but figured I would double check.

[cadillac531]

So about 15 years ago, I bought an LT5 that came with an ECU, well, unless something has to be done differently, this one doesn't work for the LT5. I installed the PROM and plugged in all 4 ECU connectors, but when I switch the ignition on, I get the SYS in the dash and it won't start.

I, then re-installed the PROM into the original ECU, and it starts fine. It, also seems as though my ECU issue is heat related. I started it and let it idle, and tapped on the ECU and the ignition didn't break up and die. I'm guessing there might be a solder or some element inside the ECU that is breaking down after 20-30 minutes of driving.

Are there solders or components in the ECU that are common to fix that maybe I can open it up and take a look? Has anyone had an ECU refurbished? Where is there a good shop to send the ECU to?

Thanks.

[conesare2seconds]

I think Marc H rebuilds them.

[cadillac531]

Originally Posted by conesare2seconds

I think Marc H rebuilds them.

OK. I also found this webpage today while doing some searching: http://www.zr1ecm.com/index.html

I'm going to contact this guy too and see what he thinks.

Thanks.

[32valvZ]

Are you sure the prom was seated 100 percent? I had a similar issue where when I dropped the hood I would hear the idle change a bit... I thought it was strange, but let it go.... until one day it wouldnt start at all. I opened up the ECU and one of the locks for the prom wasnt fully seated... car was fine after that. Have you had a chance to drive the car around after putting the ECM and prom back in? Just a few thoughts I had.... Good luck!

[cadillac531]

Originally Posted by 32valvZ

Are you sure the prom was seated 100 percent? I had a similar issue where when I dropped the hood I would hear the idle change a bit... I thought it was strange, but let it go.... until one day it wouldnt start at all. I opened up the ECU and one of the locks for the prom wasnt fully seated... car was fine after that. Have you had a chance to drive the car around after putting the ECM and prom back in? Just a few thoughts I had.... Good luck!

When I removed the PROM, the locks were pretty tight. I haven't had a chance to drive it around with the PROM re-installed, but that was the very thing I was planning to do next. I just have to find a day I can take it out and drive, while also having my wife waiting at home with the truck/trailer if it does die out.

I'll post up again once I have a chance to run it for about 40 minutes. That should be more than enough time for it to act up again.