General Information

GENERAL INFORMATION
This engine uses a fixed ignition timing system.

Basic ignition timing is not adjustable. The Powertrain Control Module (PCM) determines spark advance. The system's main components are:
- Ignition Coil
- Distributor
- Distributor Pickup
- Crankshaft Position Sensor
- Camshaft Position Sensor

The PCM supplies battery voltage to the ignition coil through the Auto Shutdown (ASD) Relay. The PCM also controls the ground circuit for the ignition coil.

The PCM controls ignition timing by turning on and off a transistor in the distributor.

During the crank-start period the PCM maintains spark advance at 9° BTDC During engine operation the following inputs determine the amount of spark advance provided by the PCM.
- Intake air temperature
- Coolant temperature
- Engine RPM
- Intake manifold vacuum

The crankshaft position sensor and camshaft position sensor are hall effect devices. The camshaft position sensor and crankshaft position sensor generate pulses that are inputs to the PCM. The PCM determines crankshaft position from these sensors. The PCM calculates injector sequence and ignition timing from crankshaft position.