Ignition Coil: Description and Operation

COIL PACK

Example: Six-Tower Coil Pack:

Coil packs come in six-tower horizontal connector and Series 5 Six tower models. Two adjacent coil towers share a common coil and are called a matched pair. For six-tower coil pack (six cylinder) applications the matched pairs are 1&5, 2&6, and 3&4.

When a coil is fired, spark is delivered through the matched pair towers to their respective spark plugs. The spark plugs are fired simultaneously but are paired so that one fires on the compression stroke of its cylinder and the other is fired on the exhaust stroke of its cylinder.

The coil is fired by the Powertrain Control Module (PCM) in accordance with the firing order of the engine.