Ignition Coil: Description and Operation

Molded Coil:

The Direct Ignition System (DIS) uses a molded multiple coil pack.

Each coil within the pack fires two spark plugs at the same time.

The plugs are paired so that as one fires during the compression stroke, the other fires during the exhaust stroke. The next time that the coil is fired, the plug that was on the exhaust stroke will be on the compression stroke and the one that was on the compression stroke will be on the exhaust stroke.

The Powertrain Control Module (PCM) determines which of the coils to charge and fire at the correct time. The coil incorporates a low primary resistance (0.57 to 0.7 ohms) which allows the PCM to fully charge the coil for each firing.