BMW X5: Ignition Management
Most of the ignition system components have remained the same for all NG6 engines for 2007. There are some minor changes to the ignition coils that apply to all versions. The coils have been optimized for more durability.
Spark Plugs
The spark plugs for the N51 and N52KP remain the same as N52. However, the N54 uses a completely new spark plug from Bosch. The spark plug design consists of a 12 mm thread which contrasts from the 14 mm design on the N52 which prevents any possibility of improper installation.
The hex on the spark plug is also a 12 point design which requires a special tool. The tool (socket) has a "thinwall" design to facilitate access in the confined area of the N54 cylinder head.
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Fig. 69: Identifying Spark Plugs
Spark Plug Diagnosis (N54)
Due to the proximity of the spark plug to the fuel injector nozzle, any divergence in the fuel spray may cause possible spark plug damage. This makes spark plug diagnosis an important part of N54 service concerns.
Information gained by the spark plug diagnosis may indicate possible fuel injector faults. Spark plug replacement interval has been reduced to 45,000 miles for the N54.
The Fig. 70 below can be used to assist in diagnosis:
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Fig. 70: Identifying Spark Plug Wear Pattern
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Emissions Management
The N54 and N52KP meet ULEV II requirements for 2007. There are not many
changes to the emission
systems on these engines. The N54 engine has 2 underbody catalysts in addition
to the "near engine" c
Performance Controls
Cooling System
The cooling system of the N54 engine consists of a radiator circuit and an
isolated oil cooling circuit. The fact
that there is an isolated oil-cooling circuit ensures that heat is not
SEE MORE:
Removing And Installing/Replacing Intermediate Levers (N52K)
Special tools required:
11 4 270
11 4 450
11 4 481
IMPORTANT: Aluminium screws/bolts must be replaced each time they
are released.
The end faces of aluminium screws/bolts are painted blue for the purposes of
reliable identification.
Jointing torque and angle of rotation must be observed with
Cylinder Head Cover
As stated before, the cylinder head cover used on all of the new NG6 engines
is made from plastic. However, the design differs between the engines due to
engine equipment.
For example, the N54 engine does not use Valvetronic and therefore does not need
the accommodation for the
VVT motor. Also,
