Ignition System: Description and Operation

ENGINE IGNITION

The ignition system consists of the following:
- ignition coil
- spark plug wires
- spark plugs
- Crankshaft position sensor (CKP)
- Camshaft position sensor (CMP)

Ignition Coil Pack - 2.0L Zetec
The ignition coil pack contains two separate coils. The ignition coils are triggered by the powertrain control module (PCM) in pairs (cylinder 1 and 4 and cylinders3 and 2) sending one ignition spark to the firing cylinder
and one to the corresponding cylinder on the exhaust stroke.

- The majority of the ignition coil energy is used by the spark plug on the compression stroke.
- The firing voltage of one spark plug is negative with the respect to ground, while the firing voltage of the other spark plug in the cylinder pair is positive with respect to ground.

Ignition coils - 3.0L (4V)
There are six separate ignition coils that are located directly above each spark plug. The ignition coils are triggered by the powertrain control module (PCM).

Spark Plugs
The spark plug:
- changes the high voltage pulse into a spark which ignites the fuel and air mixture.
- originally equipped on the vehicle has a platinum enhanced active electrode for long life.

Crankshaft Position Sensor (CKP)
The CKP provides crankshaft position and rpm information to the powertrain control module (PCM). The crankshaft position sensor:
- is a variable-reluctance type sensor.
- is a activated by a 36 minus one tooth wheel.

Refer to CRANKSHAFT POSITION (CKP) SENSOR - 2.0L ZETEC, or CRANK- SHAFT POSITION (CKP) SENSOR - 3.0L DURATEC(4V), for removal and installation procedures.

Camshaft Position Sensor (CMP)
The CMP provides a signal to the powertrain control module (PCM) when the number one piston is on the compression stroke.
Refer to CAMSHAFT POSITION (CMP) SENSOR 2.0L ZETEC, or CAMSHAFT POSITION (CMP) SENSOR - 3.0L DURATEC (4V), for removal and installation procedures.