Ignition Timing and Spark Distribution

Electronic Ignition Component Location, Part 1:

Electronic Ignition Component Location, Part 2:

The Powertrain Control Module (PCM) controls the ignition timing and spark distribution.

Crankshaft Position Sensor
The Crankshaft Position (CKP) sensor provides crankshaft position and rpm information to the powertrain control module.

The crankshaft position sensor is:
^ A variable reluctance type sensor.
^ Activated by a 36 minus one tooth wheel.

Camshaft Position Sensor
The Camshaft Position (CMP) sensor provides a signal to the powertrain control module when the number one piston is on the compression stroke.

Ignition Coil
The ignition coil contains two separate coils. Each coil fires two spark plugs simultaneously, one on the compression stroke and one 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 respect to ground, while the firing voltage of the other spark plug in the cylinder pair is positive with respect to ground.