Ignition System: Description and Operation

Ignition Components:

The CIS - Motronic engine control system is a mechanical, continuous injection system which is electronically controlled. The system is based on the Bosch KE-Jetronic fuel injection system, and combines electronic fuel and ignition control functions into a single electronic control unit (ECU). The ECU monitors various engine sensors and uses this information, compared with information stored in its memory, to precisely control the fuel and ignition systems for lower exhaust emissions, better fuel economy and better engine performance, under all operating conditions.
Ignition control is managed by the computer, through signals to a power switching transistor (power output stage) that operates the ignition coil. The signal timing (ignition timing) and duration (dwell) is determined by inputs from the coolant temperature sensor, hall sensor, air flow sensor potentiometer, and knock sensor mounted on the engine.
Only the output devices and secondary ignition components are covered in this section. For complete information on computer control of the ignition system and the sensors and signals that influence it, refer to COMPUTERIZED ENGINE CONTROLS.