It will remove logged errors & reset all learned parameters, but NOT erase the progammed information.
Exactly, so disconnecting the power supply to 're-set' the ecu wont give any increase in performance in the long-term. I have spent 100's of hours on factory mitsubishi ecu's with their software for Evo's and same goes for motecs and autronics for heaps of turbo petrols, and it will over-ride error codes which will quickly be acquired again.
The advantage in the short-term (and what defines short depends on the car in question) is that it will resort back to strandard fuel and spark maps. This is noticed greatly when mods have been added such as exhaust, the oxy sensor will 'fall' outside the normal parameters and richen the mixtures. Resetting the ecu will bring this back to leaner, greater power, but is usually back to what it was within hours. The same effect will happen with a dirty AFM. If poor fuel is used, the knock sensor will pull timing and can be very slow to recover and re-setting in that case is valuable.
And I'm referring to petrols here so spark is not applicable in the ZD case.
Resetting for a fault code like a 'blocked EGR' is a different concept as its not a map but a duel parameter input, so it will be either on/off. Depending on the sensitivity, it may or may not revert back. Boost, fuel, injector timing, afm voltage are all dependent on multiple inputs and wont be 'learned' outside a pretty narrow window which will always revert to a 'comfy zone'.
My guess is that there's some sort of capacitor in the ECU circuitry that holds enough charge, to allow a battery to be disconnected during servicing/replacement without losing the ECU's settings. Leaving it longer (overnight) allows the cpacacity to discharge, and you get a complete reset.
Exactly, or you can turn the lights on or anything else that will pull a current instead of leaving overnight. That can be a problem with some immobilisers ( subaru, new GTR and rx8's etc)
So is removing the logged errors & reseting all learned parameters enough of a reset.
What sort of info is kept in the Programed Information? (probably stuff i should stay away from
)
Pep
Your main things of interest is the fuel and ignition maps which are dependent on throttle position and engine load. You'll never modify them by pulling power to the ecu. There are software packages for different engines that can.
The only good ECU I have seen that have a true 'learning' ability is on the R35 GTR, Evo x and I think the new Sti is pretty good too. They'll adjust to exhaust, cams, intakes, etc to maintain same fuel curves.
As far as driving after re-setting, it will have no effect long-term. You can't permanently teach an ecu, it doesnt work like that.
