System Description

Ignition System Schematic:

Description
The Electronic Ignition (EI) system consists of a crankshaft mounted Hall sensor Profile Ignition Pick-up (PIP), a camshaft driven Camshaft Position (CMP) sensor, a 6 tower coil pack, and an Ignition Control Module (ICM).

OPERATION
The EI eliminates the distributor by using multiple ignition coils. Each coil fires two spark plugs at the same time. The plugs are paired so one fires during the compression cycle while the other fires during the exhaust stroke. The next time the coil is fired the plug that was on the exhaust stroke will now be on the compression stroke and visa versa. The spark that is used on the exhaust stroke is wasted but little of the coil energy is lost. Three coils are mounted together in a coil pack. The coil pack has three tach wires, one for each coil.

Timing Diagram:

PIP Output
The PIP output is a 50% duty cycle signal that provides base spark timing and fuel timing to the PCM. The CMP Battery Voltage (VBAT) is high on half of the cam revolution (180°) and low on the other half.

Computer Controlled Dwell
The PCM determines spark angle using the PIP signal to set base timing. Spout is sent from the processor to the ICM and serves two purposes: The leading edge fires the coil and the trailing edge controls the dwell time. This feature is called Computer Controlled Dwell (CCD).