General System Description

Ignition System Circuit Diagram:

GENERAL DESCRIPTION
In the Metro ignition system, ignition timing is controlled by the Engine Control Module (ECM). The ECM, after receiving signals indicating engine status (engine speed, manifold vacuum, Engine Coolant Temperature [ECT], etc.), selects the most appropriate timing setting from its programming.

The ECM sends a signal to the igniter which is connected to the negative side of the ignition coil's primary circuit. When this signal is interrupted, the field around the primary coil collapses and a high voltage is induced in the secondary coil. The high voltage induced in the secondary coil is then forced to find a ground through the secondary (coil) wire, distributor cap, rotor, secondary (spark plug) wires and across the spark plug gap to the engine block.