Ignition System

Turbocharged engines use a modified H.E.I, system called Electronic Spark Control (ESC). This system is used to control engine detonation by automatically retarding timing during periods when detonation occurs. The 4 major components of system are intake manifold, detonation sensor, controller and H.E.I, distributor.

The detonation sensor is mounted at rear of intake manifold. It can be recognized by large diameter (1.12") hex shape and single electrical connector. Sensor detects detonation and sends a signal to ESC controller, mounted in passenger compartment. Controller processes information from detonation sensor and sends a signal to special 5-pin HEI module. The signal delays spark timing and can retard ignition up to 22 degrees during heavy detonation. Retarding spark reduces detonation and possibility of engine damage.