Ignition System Service; Ignition Firing Order; Disabling Ignition System; Checking For Spark - BMW 1999-2005 M3 Service Manual

Ignition System
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Ignition System Service

Ignition firing order

Each ignition coil is mounted above the
corresponding spark plug. Cylinder 1 is
at the front of the engine.
Ignition firing order
M52 TU/M54
engine

Disabling ignition system

The ignition system operates in a lethal
voltage range and should therefore be
disabled any time engine service or
repair work is being done that requires
the ignition to be switched on.
The engine management system can be
disabled by removing the DME main
relay (arrow). The relay is located in the
electronics box (E-box) in the left rear of
the engine compartment.
CAUTION!
Relay locations may vary. Use care
when identifying relays. The main
relay has a large (4 mm 2) red wire at
terminal 30 and a large (4 mm 2)
red/white wire at terminal 87. See
610 Electrical Component

Checking for spark

CAUTION!
If a spark test is done incorrectly,
damage to the Engine Control Module
120-2
1 - 5 - 3 - 6 - 2 -
4
Locations.
2/25/2009 9:54 PM