Ignition System: Description and Operation

Electronic Spark Advance (ESA) System
The ignition system on this vehicle uses the ESA system and consists of the following parts:
^ The Powertrain Control Module (PCM)
^ The PCM analyzes the engine's ignition requirements using sensor inputs, The PCM's internal programming, and factoring in the saturation time of the ignition coil windings. The PCM then determines optimal ignition timing and signals the Ignition Control Module.
^ The Ignition Control Module: The Ignition Control Module turns ON and OFF the Primary current of the the ignition coil according to the signal from the PCM.
^ The Ignition Coil: The ignition coil is located in the distributor. When the ignition coil primary current is turned OFF, a high voltage is induced in the secondary winding.
^ The Distributor: The distributor distributes a high voltage current induced by the ignition coil to each spark plug.
^ The High Tension Secondary Ignition Wires
^ The Spark Plugs
^ The Camshaft Position (CMP) sensor: Located in the distributor in the distributor, the CMP sensor converts the crank angle into a digital voltage signal and sends the signal to the PCM.

In the ESA system, the PCM is programmed for the best possible ignition timing for every engine condition. The PCM processes information from the sensors (MAF sensor, TP sensor, ECT sensor, MAP sensor, IAT sensor, VSS, etc.) and selects the most suitable ignition timing from its memory. The ignition control module receives the signal from the PCM and triggers the ignition coil accordingly.