Ignition System: Description and Operation

DESCRIPTION
The distributor ignition (DI) system is part of the computerized engine control system. The computers in these vehicles are referred to as the Powentrain Control Module (PCM). The computer monitors information from various engine sensors, computes the desired spark timing, and signals the ignition control module (ICM) to change engine timing.

OPERATION
The distributor does not contain centrifugal advance weights, springs, or a vacuum advance unit.
The distributor has a separate ignition coil that connects the rotor through a high tension wire.
The distributor has an internal magnetic pickup assembly that contains a permanent magnet, a pole piece with internal teeth, and a pickup coil. When the rotating teeth of the timer core line up with the teeth of the pole piece, voltage is induced in the pickup coil. This voltage signals the ignition control module (ICM) to trigger the primary ignition circuit. Current flow in the primary circuit is interrupted and up to 35,000 volts is induced in the ignition coil secondary winding. This high voltage is directed through the secondary ignition circuit to fire the spark plugs.
The distributor is driven by the camshaft and mounts to the rear of the engine.
No periodic lubrication is required. Engine oil lubricates the lower bushing. The upper bushing is prelubricated and sealed.