Ignition System: Description and Operation

System Schematic Diagram:

The ignition system consists of a Single Board Engine Controller (SBEC) and its sensors, ignition coil, and distributor that sends position information to the SBEC as well as distributing coil secondary output. The Single Board Engine Controller (SBEC) controls the entire ignition system. It gives the capability of igniting the fuel mixture according to different engine conditions during engine operation by delivering a variable electronic spark advance curve. The SBEC has a built in microprocessor that continually receives input from the engine monitoring sensors. The computer then electronically advances or retards the ignition timing to provide good driveability during operation. During the CRANK-START period the SBEC will provide a set amount of advanced timing to assure a quick efficient start. The amount of electronic spark advance provided by the SBEC is determined by three input factors, coolant temperature, engine rpm, and manifold vacuum. The SBEC also receives information from the oxygen sensor and electronically adjusts the air-fuel mixture to assure the most efficient fuel burn possible. The SBEC also controls the Auto Shut-Down (ASD) Relay, which controls power to the ignition coil, fuel pump, oxygen sensor heater element, and fuel injectors.