Electronic Ignition Control

Distributor Ignition (DI) Inputs And Outputs:

CIRCUIT OPERATION
The ignition timing is controlled by the Engine Control Module (ECM) to help maintain the best blend of engine performance and emissions under all operating conditions.

The ECM uses several sensors to calculate the amount of timing based on a map stored in its memory. The timing is varied by the ECM during:
^ Starting
^ Warm up
^ Idle
^ Hot engine operation
^ Acceleration
^ Low battery voltage

Ignition Coil Cutaway View:

POWER TRANSISTOR/IGNITION COIL
The power transistor (mounted on the air cleaner housing) is a voltage amplifier that allows the signal sent from the ECM to activate the primary circuit in the ignition coil. This induces high voltage in the secondary windings of the ignition coil, providing spark to the distributor cap and plugs.