Engine Ignition

The ignition system consists of the following:

The ignition system is:

an electronic distributorless ignition system (EDIS).
controlled by an electronic engine control integrated into the powertrain control module (PCM).
set at 10 degrees before top dead center (BTDC) for base timing and is not adjustable.

The crankshaft position (CKP) sensor:

is a variable reluctance sensor.
senses a missing tooth on the crankshaft damper pulse ring.
generates a crankshaft position signal which is sent to the PCM. The PCM counts this signal for engine rpm.

The ignition coil:

changes low-voltage pulses from the PCM to high-voltage pulses.
fires 2 spark plugs simultaneously.
has 3 transformers.
- one transformer fires the spark plugs for cylinders 1 and 5
- one transformer fires the spark plugs for cylinders 2 and 6
- one transformer fires the spark plugs for cylinders 3 and 4

Spark plug wires carry high-voltage pulses from the ignition coil to the spark plugs.

The spark plugs:

change high-voltage pulses to spark at the gap, which ignites the fuel and air mixture.

The firing order is: 1-4-2-5-3-6.

Fig 1: Coil Terminal-to-Cylinder Relationship

Courtesy of FORD MOTOR CO.