General Description

GENERAL DESCRIPTION
The ignition system controls fuel combustion by providing a spark to ignite the compressed air/fuel mixture at the correct time. To provide improved engine performance, fuel economy, and control of exhaust emissions, the Powertrain Control Module (PCM) controls distributor spark advance (timing) with the Ignition Control (IC) system.
The ignition system uses a primary and secondary sub systems to accomplish timed spark distribution. The primary system consists of a low voltage trigger device which determines base timing.
The secondary system consists of the ignition coil which has primary (low voltage) windings and secondary (high voltage) windings. The secondary side of the ignition coil generates high voltage which is delivered to the spark plugs by high tension spark plug wires.
To properly control ignition/combustion timing, the Powertrain Control Module needs to know:
- Crankshaft position
- Engine speed (RPM)
- Engine load (manifold pressure or vacuum)
- Atmospheric (barometric) pressure
- Engine coolant temperature
- Camshaft position sensor