B4000 SE Cab Plus 4 4WD V6-4.0L SOHC (2001)
IGNITION COIL PACK
Coil packs come in four tower, six tower vertical connector, and six tower horizontal connector 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 and 5, 2 and 6, and 3 and 4. For four tower coil
pack (four cylinder) applications the matched pairs are 1 and 4, and 2 and 3. When the coil is fired by the PCM, spark is delivered through the matched
pair towers to their respective spark plugs. The spark plugs are fired simultaneously and are paired so that as one fires on the compression stroke, the
other spark plug fires on the exhaust stroke. The next time the coil is fired the situation is reversed. The next pair of spark plugs fire according to the
engine firing order.
