Discovery II (LT) V8-4.6L (2003)
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Spark Plug: Description and Operation
Spark Plugs
The spark plugs are platinum tipped on both center and earth electrodes. The platinum tips give a long maintenance free life.
Cleaning or resetting the spark plug gap is not recommended as this could result in damaging the platinum tips and thereby reducing reliability.
The misfire detection system will malfunction and store erroneous codes if the incorrect spark plugs are used.
Input/Output
The ignition coils provide a voltage to the spark plugs via the ht leads. The cylinder head via the individual thread of each spark plug provides the
earth path.
The spark plugs can fail in the following ways:
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Faulty component.
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Connector or wiring fault.
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Breakdown of high tension lead causing tracking to chassis earth.
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Incorrect spark plugs fitted.
In the event of a spark plug failure, misfire on specific cylinder may be observed:
