Distributor, Ignition

NOTE: The distributor used with the OBD II ignition system is located in a fixed, non-adjustable position. Do not adjust the engine base timing by rotating this distributor. Otherwise, crossfiring and damage to the distributor will result.

The 4.3L engines ignition system consist of a distributor with the following components:
^ A Hall Effect Switch
^ A Camshaft Position (CMP) sensor
^ A separate ignition coil with sealed connectors
^ The secondary wires
^ The spark plugs
^ A Knock Sensor (KS)
^ A Crankshaft Position (CKP) sensor

The ignition system is controlled by the Vehicle Control Module (VCM). The VCM monitors information from various engine sensors. The VCM computes the desired spark advance timing, and controls the dwell. The VCM also controls the firing of the ignition coil via an ignition control line to the coil driver.