General System Description
COILSThree twin tower ignition coils are combined into a single coil pack unit. This unit is mounted to the C3I module. Each coil provides the spark for two spark plugs at once simultaneously (waste spark distribution). However, all three coil packs must be replaced as a unit if one of the coils is defective. Between the coil pack and the module is a row of three terminals which run along each of the sides of the coil pack. One row of terminals is connected together by a common wire from the module, suppling all three coil packs with +12.0 volts. The other side row of three terminals are individually connected to the module. The module will only connect one coil at a time, in the correct order by suppling and removing the primary circuit ground to each coils at the proper time.
MODULE
The C3I ignition module monitors the camshaft sensor and the crankshaft sensor signals. This information is transmitted to the ECM so that the correct spark and ignition timing can be maintained during all driving conditions. During cranking, it monitors the cam signal or "Sync Pulse" to begin the ignition firing sequence. Below 400 rpm, the module controls spark advance by triggering each of the three coil packs at a pre-determined interval based on engine speed only. Above 400 rpm, the ECM controls the spark timing (EST) and compensates for all driving conditions. The C3I module must receive a cam signal then a crank signal in than order to enable the engine to start. The C3I module is not repairable. When a module is replaced, the coils must be transferred to the new module.