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.

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:

Fig. 70: Identifying Spark Plug Wear Pattern

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