Trigger Edge The trigger edge determines whether the computer is triggered by the positive or negative edge of the trigger signal. For magnetic sensors the trigger edge must be set to rising. DANGER! Disconnect the ignition coils before rotating the engine by hand. Depending on the sensor wheel slots or teeth, the signal will either be rising or falling at somewhere between TDC & 15 degrees BTDC. If unknown, connect a multi meter from the trigger wire to ground and watch the voltage level change while turning the engine slowly by hand to determine if the signal is rising or falling. If rising, select Rising (+) If falling, select Falling (-) Sync Edge The sync edge determines whether the computer is synchronised by the positive or negative edge of the sync signal. For magnetic sensors the sync edge must be set to rising. DANGER! Disconnect the ignition coils before rotating the engine by hand. Depending on the sensor wheel slots or teeth, the signal will either be rising or falling. If unknown, connect a multi meter from the sync wire to ground and watch the voltage level change while turning the engine slowly by hand to determine if the signal is rising or falling. If rising, select Rising (+) If falling, select Falling (-) Trigger pull-up resistor This parameter is only used for hall or optical sensors. It should be set to ON if the ECU is used as a stand-alone system