*Sigh* I know I've gone into details of pilot timing before on other threads. It all depends on how the ECM is set up, relative or absolute to top dead center. Relative=Main+Main-Pilot minimum separation+Pilot, Absolute=Degrees ahead of or behind top dead center. If the pilot event whether quantity is zeroed out or not, if it's timing is set that so the total pilot event plus the minimum separation encroaches past where the main event is to being, the main event bumps up pilot timing. If you set pilot timing 3 degrees ahead of the main event and it takes 6 degrees of rotation to complete injecting the pilot event plus the minimum separation, well, then its going down 3 degrees into the main event, which the ECM doesn't allow so it bumps up pilot timing to maintain the separation set in the ECM. Thus, its pretty pointless to just taper pilot timing down to zero.