Ignition Coil: Description and Operation

Ignition Coil Pack:

The ignition coil pack contains two separate ignition coils controlled by the EDIS module through two coil leads. Each ignition coil fires two spark plugs simultaneously; one plug on the compression stroke and one on the exhaust stroke. On the next engine revolution the reverse occurs. The spark plug fired on the exhaust stroke uses very little of the ignition coils stored energy. The Majority of energy is used by the spark plug on the compression stroke. Since these two spark plugs are connected in series, the firing voltage of one plug will be negative with respect to ground, while voltage of the other will be positive with respect to ground.