Ignition System: Description and Operation

The ignition system is controlled by the Jeep/Truck Engine Controller (JTEC) on all engines.
The ignition system consists of:
- Spark Plugs
- Ignition Coil
- Secondary Ignition Cables
- Distributor (contains rotor and camshaft position sensor)
- Jeep/Truck Engine Controller (JTEC)
- Also to be considered part of the ignition system are certain inputs from the Crankshaft Position, Camshaft Position, Throttle Position and Manifold Absolute Pressure (MAP) Sensors.

The ignition system is controlled by the JTEC.

NOTE: Base ignition timing by rotation of distributor is not adjustable.

The JTEC opens and closes the ignition coil ground circuit (or circuits) to operate the ignition coil (or coil packs). This is done to adjust ignition timing, both initial (base) and advance, and for changing engine operating conditions.

The amount of electronic spark advance provided by the JTEC is determined by five input factors: engine coolant temperature, engine rpm, intake manifold temperature, manifold absolute pressure and throttle position.