Ignition function: a distributorless ignition
system with individual ignition coils for
each cylinder is employed. The coils are
mounted over the spark plugs and
connect to the plugs via a short lead.
The Siemens systems use multiple spark
ignition to reduce emissions and extend
spark plug life.
Knock control. Knock (detonation)
sensors monitor and control potentially
damaging ignition knock through the
ECM. The knock sensors function like
microphones and are able to convert
mechanical vibration (knock) into
electrical signals. The ECM is
programmed to react to frequencies that
are characteristic of engine knock and
adapt the ignition timing point
accordingly. See
120 Ignition System
for further details.
Note:
M52 TU and M54 engines are designed
to operate best with fuel octane of at
least 91 anti-knock index (AKI). The
adaptive engine management system,
however, will allow use of fuel rated 87
AKI.
Siemens DME MS 42.0
Engine-General
http://ebahn.bentleypublishers.com/BMW/3/E46/Repair%20Manuals/1...
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Summary of Contents for 1999-2005 M3
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