The base line settings are stored in a table, called the fuel table or fuel map. There are literally hundreds of squares corresponding to different values of throttle position and engine RPM. Looks like a spread sheet. Each square contains an entry to control the turn on time of the fuel injectors at that combination of throttle position and RPM. It can’t be changed. It’s flashed onto the chip in the ECU from the manufacturer. If you send your ECU out for a flash, they over-write the table with a new one. That’s your baseline fuel mapping. You don’t have to activate it or turn it on. It’s always active.
The baseline is only good for the perfect engine on the perfect day. The ECU needs a way to make minor tweaks on fuel delivery in order to compensate for the real world or mechanical changes. Very minor tweaks. That function is called fuel compensation or fuel trim. It references the output voltage of the O2 sensor. That voltage corresponds to the required Air Fuel Ratio. It’s nothing more than a control loop where-as the ECU attempts to maintain a constant voltage from the O2 sensor, and makes that adjustment by changing fuel trim. Maintains a constant voltage - thus maintains a constant AFR. Works, in theory, just like your cruise control except we’re not allowed to change the set-point. It doesn’t change any values in the main fuel table. Instead, there’s an identical table of throttle position vs RPM where these fuel trim values get stored. Called the Long Term Fuel Trim. Again, hundreds of squares. Unless the engine is operated at each one of those conditions, the value in that square won’t get updated.
Even with today’s engines, this is technology that is over 20 years old. Don’t give it more credit than it deserves. There are no algorithms. There’s is no learning new settings. There is no establishing new constants. It’s not AI. And it certainly has nothing to do with shooting. It’s just a controller. The ECU just reads a setting, does some basic math based on input from a sensor, and turns on a fuel injector. That’s all. Each of the hundreds of combinations of throttle position and RPM in the fuel table has a dedicated setting. The ECU interpolates between the squares in order to make it a smooth transition across the entire operating range as it goes from square to square.
Idling doesn’t hurt anything. But it doesn’t do anything either. It’s not some magic wand or required thing you have to do in order to establish a new baseline or activate a new tune or set a new constant. There’s no such thing.
So, all idling will do is update that one fuel trim value, in that one square, for idle conditions. There are still hundreds left to update, if it’s necessary. You just need to ride around and it takes care of itself. Heck, if all of this idling stuff was required, then we’d have to idle for 10 minutes every time the weather changed. So, start the motor, put on your helmet and just go.
If you don’t have any formal training in fuel injections systems, that’s OK. There are hundreds of videos, and on line courses on the internet that will teach you all of this. Specifically search for fuel maps, fuel tables, long term fuel trim, short term fuel trim, closed loop operation, open loop operation, three-way catalytic converter, and O2 sensors. That will peak your interest and you can go on from there. Or, forget about it all and just ride.