spark plugs BMW X5 2002 E53 M54 Engine Workshop Manual

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M54engMS43/ST036/6/2000
RZV IGNITION SYSTEM
The Siemens MS43.0 system uses a multiple spark ignition function. The purpose of mul-
tiple ignition is:
• 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
longlife 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 cur-
rent is also lower and a longer period of time is required to build up the magnetic field in the
coil(s).
• Low battery voltage = less multiple ignitions
• High battery voltage = more multiple ignitions
The 240 ohm shunt resistor is still used on the MS43.0 system for detecting secondary igni-
tion faults and diagnostic purposes.
MS 43.0