Engine Ignition
WARNING: This page is about a different car, the 2004 Mercury Monterey and 2004 Ford Freestar. However, it is still accessible from the selected car via links, so may be relevant.
The electronic ignition (EI) system for the 3.9L and the 4.2L engines consists of the following components:
- crankshaft position (CKP) sensor
- ignition coil
- spark plugs
- spark plug wires
The crankshaft position (CKP) sensor:
- is a variable reluctance sensor.
- is mounted on the engine front cover.
- is triggered by a 36-minus-1 tooth trigger wheel located on the crankshaft pulley and damper.
- provides base timing and crankshaft speed (rpm) to the powertrain control module (PCM).
For additional information, refer to CRANKSHAFT POSITION (CKP) SENSOR .
The ignition coil:
- is controlled by the powertrain control module.
- fires two spark plugs simultaneously.
The spark plugs:
- ignite the fuel and air mixture.
- are platinum enhanced for long life.
The spark plug wires:
- carry high voltage pulses from the ignition coil to the spark plugs.