Ignition Timing: Function
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2004 Land Rover Discovery, 2003 Land Rover Discovery, 2002 Land Rover Range Rover, 2002 Land Rover Discovery, and 2001 Land Rover Range Rover. However, it is still accessible from the selected car via links, so may be relevant.
At engine start up, the ECM sets ignition timing dependent on ECT information and starting rev/min from the CKP. As the running characteristics of the engine change, the ignition timing changes. The ECM compares the CKP signal to stored values in its memory, and if necessary advances or retards the spark via the ignition coils.
Ignition timing is used by the ECM for knock control.