I have done about 15 proms for my 91 TBI with the 8746 ECM.
I have never had a problem. Today I put in a prom I had just burned and after start up and driving for about 5 minuits, I got a flickering SES light, the engine started cutting out/missing and my BL numbers went from 50 to 200. Then the engine would run normal, then it would happen again.I pulled over and replaced the prom with several back up proms which I know are good but I had the same problem with all of them. I didn't think I would make it back home.

I didn't get any codes when the light came on or at any time during driving.

The only thing I can think of is somehow I screwed up the socket
in the ECM when I put the new chip in. I looked at the socket with a magnifing glass, but I couldn't see anything obvious.


I appreciate all thoughts or suggestions.Thanks.............bob

 

i had that happen to me once when i didn't have the adaptor wasn't seated all the say. same thing, car ran like crap, SES light flashed like crazy. so it could very possibly be your socket.

 

the contacts can lose their tension after time. I little gentle prying with a really fine screwdriver might help.

 

as always, thank you very much for the help. At least I am on the right track. Will try prying the contacts out for better contact.
If no luck, I am off to the yard for another ECM. Haven't seen an easy way to replace the socket in the board.
IS there a ZIF adapter available? I know craig moats makes one but I don't think it will work on the 8746. THANKS AGAIN YOU GUYS FOR THE RESPONSE .....................bob

 

If you can't fix it, then it's a candidate for desoldering the socket and installin a ZIF in it's place.

The *itch is that some of the traces are on both sides of the board, and can be a PITA to desolder without loosening them. But it can be done.

So far my success rate is 2 good for 6 attempts.