ECM tuning issue

[92gtp]

Hello,

After tuning my '92 Grand Prix GTP ECM using TunerPro and Moates.net chip/harware my engine doesn't idle correctly and stall by itself. the only thing I can think of is the change I made to the initial spark advance. I install back the original eprom but it is still doing the same thing.

I tried another ECM/Eprom and the problem goes away. Is the ECM itseft could went defective? I'm scared to interchage the original eprom to not blow the otherone.

Is there a learning being done when first installing a new eprom? is their a way to reset this?

thanks

[92gtp]

After looking up many hours on Google I found myself the answer:

1. Unplug all cables from the ECM unit to ensure no power from the car battery get to it.
2. Let it sit for 8 hours to defeat the internal ECM battery.
3. Wait another 4 hours to ensure internal reset.
4. Plug cables back to the ECM.
5. Start the engine and let it run idle for 15-20 minutes (coolant temp has to get higher then 85C). This will allow the relearn procedure.
6. Take off with the car to verify if it works as before.

Hope this will help other who may encounter the same issue.

[SappySE107]

No way. It takes 5 seconds to reset the PCM. Sounds like a bad burn, or a bad pcm.

[pocket-rocket]

I usually pull the ECM fuse by the fuel pump relay and count to 10 to reset mine.

I also use this trick so I can turn the engine over with the starter till I get oil pressure after an oil change so it doesn't run to avoid dry starts.

[robertisaar]

i pull both ECM fuses... don't know why, but sometimes it seems like just the underhood one won't do it.

[92gtp]

good to know... but I really don't know why it didn't work that way for me that time. I usually take the ECM right out so it is completly without power for well longer than 10 seconds... but hey it would be hard to figure this one out...

thanks guys for your replies!