Ignition Coil: Description and Operation
Coil PackExample: Six-Tower Coil Pack:
A coil in a coil pack is turned on (for example is coil charging) by the PCM, and is turned off when firing two spark plugs at once. The spark plugs are paired so that as one spark plug fires on the compression stroke, the other spark plug fires on the exhaust stroke. The next time the coil is fired the order is reversed. The next pair of spark plugs fire according to the engine firing order.
The ignition coils are triggered by the powertrain control module in pairs (cylinders 1 and 4 and cylinders 2 and 3) sending one ignition spark to the firing cylinder and one ignition spark to the corresponding cylinder on the exhaust stroke.