HEI With Electronic Spark Control (ESC)

Electronic Spark Control (ESC) adds detonation detection and correction functionality to the base HEI system. This allows maximum performance due to aggressive spark advance schedules from the vacuum and centrifigul advance devices.

The HEI ignition module is modified to communicate with an external detonation module via a four-wire connection. The external detonation module utilizes a detonation sensor and possibly a "tip-in" vacuum sensor. The latter, when used, provides extra spark advance during acceleration (tip-in) conditions.

The detonation module is an integral part of the ignition module triggering loop. If the four-wire connector is unplugged, a no-spark condition will result.

Beware of mistaking the four-wire connector for an EST connector. If unsure, look for a vacuum advance along with the four-wire connector. If one is found, it's an HEI-ESC system. Otherwise, it's an HEI-EST-ESC system.