General System Description

PURPOSE
Generate sufficient spark to ignite air/fuel mixture and direct it to spark plugs at each cylinder.

DESCRIPTION
This vehicle uses an Engine Control Module (ECM) controlled electronic ignition system. Components include:

1. Ignition coil.
2. Camshaft driven distributor with integral crank angle and camshaft sensor.
3. Power Transistor.
4. Distributor cap and high tension wiring for distributing high voltage to the spark plugs.

CRANK/CAM ANGLE SENSORS
The Crank/Cam Angle Sensors are photo-diode types that provide the ECM with signals regarding engine RPM and #1 cylinder TDC (camshaft position). Together with other inputs, the ECM calculates ignition timing over the range of vehicle operating conditions.

POWER TRANSISTOR
An ECM controlled power transistor is used as a switch to regulate current flow through the coil primary circuit. Each time current flow is interrupted, high voltage is induced to fire the spark plugs. Except for the initial setting, timing is controlled by the ECM.

SECONDARY IGNITION COMPONENTS
A distributor cap, rotor and high tension wires are used to direct high voltage from the coil to each spark plug at the appropriate time as calculated by the ECM.