Jeep Wagoneer/Commando/Cherokee 1984-1998

General Information


The ignition system consists of:

an ignition coil
an ignition control module (1987-90 models only)
an ignition distributor containing a rotor and camshaft position sensor
The Electronic Control Unit (ECU), also known as the Powertrain Control Module (PCM)
Crankshaft position, throttle position and MAP sensors

The amount of spark advance provided by the engine controller is based on five input factors. The factors are coolant temperature, manifold absolute pressure, engine speed, manifold air temperature and throttle position.

Base ignition timing is not adjustable. The controller opens and closes the ignition coil ground circuit to adjust ignition timing for changing engine operating conditions.