IGNITION SYSTEM
DISTRIBUTOR TYPE IGNITION SYSTEM
NOTE:The distributor type ignition system may be referred to as Electronic Spark Advance (ESA) system.
The ignition system uses the Engine Control Module (ECM) for determining ignition timing (spark advance). The ECM determines ignition timing (spark advance) based on various input signals. Following input signals may be used: engine coolant temperature, throttle position, oxygen sensor, engine RPM, vehicle speed sensor, A/C switch, brakelight signal, airflow meter, knock sensor, electrical load, MAP sensor and cranking (starter) signal. Input signals may vary on model application. Integrated (ignition coil on distributor) and remote ignition coil designs are used depending on model.
Crankshaft position and engine RPM input signals are delivered to the ECM by pick-up coil(s) in the distributor.
NOTE:Pick-up coils in distributor may be referred to as camshaft position sensor on some models.
ECM uses pick-up coil input signals to switch primary ignition circuit on and off. Primary circuit is turned off when ECM delivers a signal to ignitor on the IGT wire, causing ignition coil to fire the spark plug. After delivering a command to turn off primary circuit on the IGT wire, the ECM monitors IGF circuit to ignitor to ensure primary switching occurred. See appropriate wiring diagram in the WIRING DIAGRAMS - 2.2L article for wire color and application.
Sunday, April 5th, 2009 AT 5:31 PM