Ignition Coil: Description and Operation

Ignition Coils:

The ignition system on this vehicle features a multiple coil configuration and is known as coil near plug. There are two styles of ignition coil assemblies (1,2). The engine could have either style. The ignition coil mounting bracket is attached to the rocker cover. The secondary ignition wires are short compared to a distributor ignition system wire.




The 8 ignition coils or modules are individually mounted above each cylinder on the rocker covers (3). The coils/modules are fired sequentially. There is an Ignition Control (IC) circuit for each ignition coil or module. The 8 ignition control circuits are connected to the PCM. The PCM triggers each ignition coil/module individually and makes all timing decisions. The ignition coil or modules are supplied with the following circuits:
^ The ignition feed circuit
^ The ignition control circuit
^ The ground circuit
^ The reference low circuit

The ignition feed circuits are fused separately for each bank of the engine. The 2 fuses also supply the power for the injectors for that bank of the engine. Each coil or module is serviced separately.

This system puts out very high ignition energy for plug firing. Less energy is lost to ignition wire resistance because the ignition wires are shorter. Since the firing is sequential, each coil has 7 events to saturate as opposed to the 3 in a waste spark arrangement. Further more, no energy is lost to the resistance of a waste spark system.