Ignition System: Description and Operation

GENERAL DESCRIPTION
The Computer Controlled Coil Ignition (C3I) system consists of a crankshaft position sensor, knock sensor, the Electronic Spark Timing (EST) portion of the PCM, an ignition control module, four ignition coils, eight spark plugs, and the related connecting wires.

Ignition Current Flow:

The ignition system uses a waste spark method of spark distribution. There are 4 ignition coils, each firing two cylinders at once. One cylinder is on the compression cycle, while the other is on the exhaust cycle. The ignition module triggers the correct coil, based on signals from the crankshaft sensor.

COMPANION CYLINDERS
Cylinders 1 & 6
Cylinders 2 & 3
Cylinders 4 & 7
Cylinders 5 & 8

The primary inputs for ignition control are the crankshaft sensor and knock sensor. The ignition module controls spark timing under 400 RPM and must receive a "sync-pulse" followed by a Crank Signal in that order to enable engine start up. The ignition module monitors the crankshaft sensor signals and based on these signals, sends a reference signal to the ECM to allow the correct spark and fuel injector control to be maintained during all driving conditions.