Engine Control Module: Description and Operation

The SBEC houses circuits needed to power the ignition coil, alternator field and fuel injector, and energizes the automatic shutdown (ASD) relay. The SBEC also receives a signal from the distributor. If no distributor signal is received, the ASD relay is not activated and power is shut off from the fuel pump and ignition coil. A voltage converter in the SBEC reduces battery voltage to a regulated 8 volt output which powers the distributor.
The SBEC is a digital computer which contains a microcompressor. Input signals from various switches, sensors and components are sent to the SBEC, which then computes the fuel injector pulse width, spark advance, ignition coil dwell, idle speed, purge, cooling fan turn on and alternator charge rate.