PCM question

[Grey_2004_Neon]

I was wondering, whenever the negative battery cable is disconnected, does the PCM have to "re learn" the settings it had, before battery ground cable disconnection? If so, how far does the car need to be driven, before the re learn process is done?

[neoncrazy101]

I've never experienced it with my 2gn, even after completely swapping PCM's that were unplugged for months. On my 1gn's though, I've had them where they start for a few seconds and then die after a long battery disconnect. Then I just start them back up and its good. That was always on a 1gn though.

You still having issues with yours running?

[Grey_2004_Neon]

Nope, got it going finally this morning, new reman alternator, and the battery sensor. Drives and runs good

[occasional demons]

Just depends on the PCM, and how much actually changed in between power down, and power up.

It took over 700 miles for my 2001 to warm up to the fact I installed a Magnum cam, and ported the head along with a fresh timing belt and water pump.

It ran horrible, and got crappy fuel mileage. It is why I am here, trying to figure out what went so wrong. Then one day, it was like it flipped a switch, and all was good. Power was up, and fuel consumption was down, and it never looked back. I was so close to going back to totally stock too.

I had it disconnected for over two weeks, between cleaning, porting and waiting for the valve grind to be done. I guess it just didn't, like being awakened from it's slumber. I have no idea why it took so long to straighten out. Everything checked out fine, it just didn't want to cooperate.

So they can be simple, or they can be very frustrating, they are just like people...

[NickKo]

Just depends on the PCM, and how much actually changed in between power down, and power up.

It took over 700 miles for my 2001 to warm up to the fact I installed a Magnum cam, and ported the head along with a fresh timing belt and water pump.

It ran horrible, and got crappy fuel mileage. It is why I am here, trying to figure out what went so wrong. Then one day, it was like it flipped a switch, and all was good. Power was up, and fuel consumption was down, and it never looked back. I was so close to going back to totally stock too.

I had it disconnected for over two weeks, between cleaning, porting and waiting for the valve grind to be done. I guess it just didn't, like being awakened from it's slumber. I have no idea why it took so long to straighten out. Everything checked out fine, it just didn't want to cooperate.

So they can be simple, or they can be very frustrating, they are just like people...

Maybe I am imagining this, but it seems to me (based on my experience) that the 2nd gen PCM's have a longer 'learning curve', compared to 1st gen PCM's - But once it 'learns', it's good.


- Nick