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Home >> Saab >> 1989 >> 9000 Base, Standard >> Repair and Diagnosis >> Engine Performance >> Theory and Operation >> Theory/Operation >> Ignition System >> Ignition Timing Control System >> Detonation Retard Operation
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Detonation Retard Operation

A detonation sensor detects any knocking in the engine and applies a signal to the ECU which then automatically retards ignition timing in accordance with programmed parameters and engine load and speed input signals received.

The knocking related ignition timing is controlled on individual cylinders. The ignition timing may vary from one cylinder to the next. However, load related timing is controlled for all cylinders together.