Direct Ignition Timing Control System

Fig. 93 Direct Ignition Timing Control System:

CIRCUIT OPERATION
The ignition timing is controlled by the ECU to help maintain the best A/F mixture under all operating conditions.
The ECU uses several sensors to calculate the amount of timing based on a map stored in its memory. The ECU varies the timing during:
1. Starting
2. Warm up
3. Idle
4. Low battery voltage
5. Hot engine operation
6. Acceleration

Fig. 94 Power Transistor:

POWER TRANSISTOR
The power transistor, located on the L.F. of the cylinder head, is a voltage amplifier that allows the signal sent from the ECU to activate the primary circuit in the ignition coils (4). This induces high voltage in the secondary windings.