Description & Operation

A solid state ignition system is used on the Nova. Two different ignition systems are used depending upon engine application. On models with 4A-LC (single camshaft) engines, vacuum and centrifugal advance is used to advance spark timing. On models with 4A-GE (dual camshaft) engines, an Electronic Spark Advance (ESA) system is utilized. Variations between these two systems will be noted when necessary.

On the 4A-LC models, secondary voltage will be induced by the pick-up coil inside the distributor and used to generate the ignition signal. As the distributor rotates, the magnetic flux passing through the pick-up coil varies because of change in air gap between pick-up coil and pole piece.

This provides alternating current from the pick-up coil and turns the module on and off. When this happens, the ignition coil primary current is turned off and on. This allows high voltage to enter the ignition coil secondary winding and spark plugs.

On 4A-GE models, secondary ignition is induced by the pick-up coils and monitored by the Electronic Control Module (ECM). The ECM is programmed to deliver optimum ignition timing under varying operating conditions. This accomplished by monitoring sensors from different engine operating parameters and adjusting ignition timing accordingly.