Detonation (Knock) Retard Operation

The MX-3 1.8L, 929 and turbocharged models use an ignition retard system consisting of knock sensor(s) and ECU or knock control unit (turbocharged only). The knock sensor detects engine detonation (knocking) in the engine and sends a signal to ECU or knock control unit. This signal is modified by the knock control unit (if equipped) and sent to the ECU.

Timing can be retarded up to 6 degrees, depending upon amount of knocking. On turbo models, knock control unit also controls turbocharger wastegate solenoid valve, lowering turbo boost pressure up to 2.2 psi during knock conditions.