Okay at the risk of sounding especially retarded, this question has been bothering me for a while and though I think I know the answer, I'm just not sure.
I know on older cars you would "burn" a chip and that was always there either replacing or piggybacking that overrode the factory instructions to keep the custom program. My question is on a car that you have the computer itself, such as the later LT1/LT4's "tuned" or programmed, what happens to that when the battery is removed for a period of time or replaced? Does it revert back to the factory default or somehow is the custom tune now "permanent" unless you change it?
The "tune" as you call it is burned or flashed into the memory chip depending on the model year. The older models that require chip removal for changes revert to the "tuned" settings as a start when the battery is removed. As the car is driven changes are recorded to the block learn cells to accomodate changes in the air/fuel ratio that deviate from the tune. It's these changes that are lost when battery power is lost. I'm not sure how the newer models, the flash pcm types, handle this. My experience has been with a '94 that reverted back to "tuned" settings after battery removal, but I can't speak with certainty about all flash type pcm's.
I know on older cars you would "burn" a chip and that was always there either replacing or piggybacking that overrode the factory instructions to keep the custom program. My question is on a car that you have the computer itself, such as the later LT1/LT4's "tuned" or programmed, what happens to that when the battery is removed for a period of time or replaced? Does it revert back to the factory default or somehow is the custom tune now "permanent" unless you change it?
There is no difference. You are "burning a chip" in both cases.
Once you "tune" it it doesn't change unless you reprogram it again. Older cars you pull the prom and reflash it, the newer cars you can reflash thru the aldl port. So if you leave the battery off, no you dont loose the reprogram.
Corvette Store
"Life" of a tune?
