My 82 was running like a champ until I notice my volt/battery gauge starting twitching like this:



When this twitching started is when I started having problems keeping the car running. I would turn the ignition on and the check engine light was blinking (like in the third video below). Once the blinking stopped it would start, but It did take longer to crank over. It would only run for maybe 5 seconds and then the engine would die and the check engine light would fade out. I did this about 5 times in a row and then the car finally stayed running and ran completely normal until I got him home and parked in the garage.

I went ahead and checked out the alternator. I found where the positive cable was connected, the whole thing moved.



I'm pretty sure it's not supposed to do this, so replaced the alternator. That thankfully fixed the issue with the twitching volt/battery gauge. I'm still having issues with the check engine light blinking/flashing when the ignition is on. When I started it today, it idled like it normally does when its cold, but then the check engine light came on for a second and it surges. The idle will go back to normal but it does it again. It is at least not dieing after 5 seconds once the alternator was replaced. Not sure if that is a coincidence or actually help. Below is a video showing what it is doing.



I also checked for any codes and it is only flashing 12 on the check engine light. I have no idea if that alternator had anything to do with this either. I also made sure all the connections were tights on the battery and alternator. Maybe I have a ground problem somewhere?

I am also slooowly learning how to work on this car and have read through the sticky on 82's but I'm not sure I'm finding what might be wrong. Help!!! Pretty please?

 

I would go and buy a manual first and formost. Than harbor freight has the cheap snanner for our cars. Chances are the alternator flickering and the car stalling out put it into a learn mode. This will cause the idle to be a little strange from time to time but nothing to noticeable. It may idle at 800 one day then 600 the next for the next 100 miles.

Read the 82 corvette sticky and check the must do's!!!
Plenum gasket is a must do or it will drive you crazy! GM siliconed it to seal with no gasket and IMO it's the main reason CFI got a bad reputation!

 

Thank you for the reply!

I ended up replacing the ECM and now its running like normal again. No more flashing check engine light with the ignition on and no surging idle anymore. Even went for a 2 hour cruise and it ran great. I really do think my old alternator fried my ECM.

 

Anything is possible with these old electronics the best advice I could give is, make sure all the ground wires are in good condition and follow the must do sticky for 82 vettes. It's simple and cheap for the most part.
Good luck!