Electronic Spark Control System (ESC)

The 4 basic components of the Electronic Spark Control (ESC) system are the detonation sensor, HEI (EST) distributor, controller, and the ECM. When detonation (engine knock) occurs, the detonation sensor sends an electrical signal to the ESC. The controller amplifies this signal and transmits it to the ECM. The ECM will retard spark timing until signals from the detonation sensor stop.

Fig 1: Schematic of Electronic Spark Control System