900 Series

Ignition advance is controlled by the ignition ECU. Inputs from the fuel injection ECU, Hall Effect sensor, and coil are used by the ECU to calculate advance. A sensor detects any knocking in the engine and sends a signal to the ECU, which then retards ignition timing. On 900 Series Turbo, a pressure signal from the air intake duct controls a distributor-mounted diaphragm which retards timing.