Well after searching and searching, and reading numerous threads I have come to the conclusion that most folks reset their ECU's differently. What I mean is the method. I have read disconnecting the negative battery anywhere from a few minutes all the way up to 20 minutes, and then starting the car and letting it idle anywhere from a few minutes up to 20 minutes. I also read a few threads where folks have added after the first two steps to drive around for 15 or 20 minutes.
So my question is will a minute or two do it for a reset, or does one actually need 20 minutes? Also does one need to idle the car for a few minutes afterwards, or does one need 20 minutes of idling? Does one need to drive around afterwards or not?
I'm pretty sure any of the above mentioned ways will work just fine, but what is all that is required?
Now for the final question, what mods actually require an ECU reset? In other words does installing a catback require one? Or just intake/fuel related mods?

 

I take my negative terminal off for a few minutes, idle it for 15. And yes, it's recommended in the Magnaflow instructions to take the negative terminal off while installing their catback to reset the ECU.

Hope that helps.

Daniel

 

The people that remove it for 20 minutes just want to be SURE the ECU reset. You could probably do less. If you put it back on and your radio stations are still programmed, it didn't reset.

The idling - let it go for 20 minutes, yes. The car has to completely relearn the idle characteristics. I've learned that you can't rush it. I tried to idle for 10 minutes and drive home - the car stalled at every red light.

Driving around after - not entirely necessary. Same concept as the idling - car has to relearn the air/fuel characteristics under driving conditions as well. I usually skip that step, as I've learned that the car gradually learns them over a week or two.

What mods require it? Breathing mods. If it involves intake or exhaust, you'd be wise to reset it. Otherwise, the computer is running air/fuel curves that don't exist (because you changed the air/fuel characteristics).

And if you doubt my expertise, just remember one thing - I've performed 5 intake swaps, 5 exhaust swaps, and had an issue with my negative terminal falling off the battery. So I've done this procedure at least a dozen times. Probably more. I don't even program the radio stations anymore.

 

Black is right...just got the RMR intake on my Lancer and forget to disconnect the neg batt term. Bad gas mileage...so, I reset it. Just like a minute or so. Let idle for a few minutes, then went around on a easy drive around town. No stalling issues...no nothing. Better gas mileage now. Hope that helps.