Ignition Timing Control System

Ignition timing is adjusted to engine operating conditions by the electronic control unit. Optimum spark timing for every driving condition is contained in the microcomputer memory. Signals from cylinder head temperature, crank angle and detonation sensors, air flow meter, throttle valve switch, and car speed sensor, depending on application, are used by the micro-computer to calculate correct ignition timing.

On turbocharged models, engine knock is monitored by the detonation sensor which transmits a signal to the control unit. The control unit adjusts ignition timing to eliminate engine knock.


When coolant temperature is below 95'F or the throttle valve is closed, spark timing is advanced electronically.