Except those values are all intended to optimize the engine, so resetting them is more likely to result in a performance drop than gain. Even worse the defaults like O2 are likely to be on the conservative side so that they can claim better CO2 values & efficiency when the car rolls off the factory floor.
Erm, well the ECU has a target O2 value, even if they manually set those values before the car starts, once the O2 sensor provides feedback (which even in SA winter will be within minutes, probably less than a minute), the values will quickly be replaced. The values are never static, they may simply be saved for when you start the car again.
I know though that you can reset the overall throttle response feel with a laptop uplink. e.g. BMWs driven by a conservative driver for a while have a very sluggish feel to them because the electronics have adapted. Reset that & it feels more responsive.
Probably the O2 adjustment but if you drive at full throttle there will be no difference because the ECU runs at Open Loop mode while @ wide open throttle. It is the same for all ECUs and all fuel injection methods. Open Loop mode ignores any stored values and also ignores input from the O2 sensor and uses directly the data programmed into the EEPROM. The reason is to prevent knock and possible engine damage (knock at wide open throttle can very quickly destroy an engine, too quickly for on the fly adjustment by the ECU to be safe).
So if they say the car feels sluggish it is because they are driving at partial throttle and the mixture is lean but I assure you that the ECU cannot learn driving style or even run leaner than the target value. An engine runs too lean has a propensity to knock (leaner mixtures have much much higher chances of knock), the engine also runs exponentially hotter the leaner the mixture (so much so that a car running just a little too lean will melt a spark plug and the exhaust glows red). There is NO WAY a OEM would allow the ECU to adjust leaner than the target value. The target value wouldn't change regardless of driver. The engineers determine the target value when designing the engine. It isn't something that is adjusted by a lowly BMW mechanic.
There is however *usually* an overall multiplier that can be adjusted by those types of tools used by garages (usually, but it depends on the fuel injection method used). The adjustment however is a SINGLE value and is NOT specific to RPM and LOAD (IE. it is an overall value). The reason for this value is that sensors (like the mass flow and exhaust O2 sensor) may stray from the real values and this multiplier allows it to once again report the correct values. They do this kind of adjustment by running the car at a
predetermined RPM and LOAD and then setting that value according to their
specifications. It is then accepted that an OEM car will run withing spec throughout the map if that single value was correctly adjusted. That value cannot be adjusted by the ECU, it is adjusted with a tool ONLY.
OEMs don't willy-nilly allow their garage techs to adjust engine maps. The reasons should be obvious. Guess it may be possible that some OEMs allow it but I know for a fact that OEMs like GM don't allow that sort of thing (The tool cannot adjust engine map, just reprogram already created maps and adjust a value or two here and there).
You sure this person is qualified to own an ECU equipped car? I'm sure that works for his alarm clock, but a 200k car. lol
