900 Turbo Convertible L4-1985cc 2.0L DOHC Turbo EFI (1994)
Ignition Control
When the engine is started, the ignition timing is 10° BTDC. To assist starting at an engine coolant temperature below 0° C, the ECM will ground
the trigger lead concerned 210 times per second from 10° BTDC to 20° ATDC, producing a "multispark". This function ceases at engine speeds
above 850 rpm.
During idling, a special ignition control curve is used. Normal pre-ignition is approx. 6-8°.
If the engine speed drops, e.g. when the radiator fan is switched on, the pre-ignition increases up to 20° BTDC in order to increase engine torque
and restore engine speed. In the same way, ignition is retarded and engine speed is increased.
Ignition control during idling compensates for rapid changes in engine idling speed.
When the throttle position moves away from idling, ignition control changes over to normal control depending on load and engine speed.
