do you need to retune your car after u disconnect the negative battery terminal?

 

nope...

 

No. The tune stays in permanent memory. You may dump data in the adaptive learning, depending on how long the battery is disconnected, which MAY cause some drivability issues for the first xx miles but most people do this on purpose claiming it improves performance. Unless you drive very aggressively all the time, adaptive learning can cause a drop in perceived performance.

I've done it on a few occasions and my butt dyno perceived a minor increase in performance.

 

Nuke is right. It is stored in NVRAM just as the stock flash would have.

 

Nah man it stays. Just like the stock computer stays.

 

Like everyone here says, nope. Actually, you may feel a good 'reboot' once you connect the battery back up. It'll feel like the first time you drove it before the algorithm began factoring in all the voodoo magic variables that it does LOL.

Many of us regularly do this simply for this reason alone.

 

NOPE ~ It's unanimous! When I had to replace out my battery, it was like loading the custom for the very first time. =-)

 

https://mustangforums.com/forum/v6-s...ut-tuners.html