Ignition Timing Control

The ignition timing control system provides the two following types of controls:
1. Detonation Control-- When detonation control signal is applied to the igniter from the ECU, the igniter retards the ignition timing to such an extent that detonation is eliminated (maximum 12° in crank angle). Should the harness from the detonation sensor have an open or short circuit, the igniter retards the ignition timing by a fixed angle (approximately 8° in crank angle) to prevent detonation (fail safe feature).
2. Cold and High Altitude Timing Control-- When the engine coolant temperature is low or vehicle is operating at high altitudes, the system causes the ignition timing to advance approximately 5°, to improve mileage and driveability.