do custom tunes make adjustments off the stock tune?

[dream07]

I can't find an answer, so here it is:

"Are custom tunes that are emailed and loaded by a handheld tuner just making small changes to the existing stock tune files on the computer or is it a completely separate set of data that completely replaces the stock tune files?"

Reason: I have no idea if my "stock tune" is corrupted, as I bought it used and without knowing if the thing had a custom tune loaded, etc.

If I buy a SCT X4 handheld and tunes from say Bama, and you copy the stock tune into the handheld, does their tune completely replace that entire tune or will my corrupted tune mess up their tune?

 

[07TGGT]

It loads an entirely new file(tune).

 

[redfirepearlgt]

Your PCM can be reflashed to factory with the proper tune by a Ford service center. Some Speed shops also have that ability like the one I use locally.

This way you know the tune is loaded and is the correct stock tune for your application. Now you have a solid basis to troubleshoot from if problems still exist.

The tune in your car will be come the factory default tune in the handheld when you load an aftermarket tune of your choosing. IT will not effect the tune you are loading to the car, nor will saving it on your handheld effect any other tune stored in the handheld currently. The tune currently in the car will become the default factory tune when you get ready to unmarry the handheld from that car to use on another. E.G. I put my 13 back to stock. I reloaded the factory tune. Now the handheld is unmarried and can be used on the next car.

 

[dream07]

Thanks guys, I was hoping that was the way it worked.