Ignition System

Siemens system uses a multiple spark ignition function. The purpose of multiple ignition is to provide clean burning during engine start up and while idling (reducing emissions). This function helps to keep the spark plugs clean for longer service life (new BMW long-life plugs). Multiple ignition is active up to an engine speed of approximately 1350 RPM (varied with engine temperature) and up to 20 degrees after TDC. Multiple ignition is dependent on battery voltage. When the voltage is low, the primary current is also lower and a longer period of time is required to build up the magnetic field in the coil(s). Low battery voltage equals less multiple ignitions, high battery voltage equals more multiple ignitions.