Chart C-4F-2 C(3)I Misfire Under Load 1986-1987 3.0L (VIN L)

CHART C-4F-2

C(3)I MISFIRE UNDER LOAD 1986-1987 3.0L (VIN L)
Circuit Description:
The C(3)I uses a waste spark method of spark distribution. In this type of ignition system the ignition module triggers the #1/4 coil pair resulting in both #1 and #4 spark plugs firing at the same time. #1 cylinder is on the compression stroke at the same time #4 is on the exhaust stroke, resulting in a lower energy requirement to fire #4 spark plug. This leaves the remaining high voltage to fire #1 spark plug.

CHART C-4F-2C(3)I MISFIRE UNDER LOAD 1986-1987 3.0L VIN L:

Test Description: Numbers below refer to circled numbers on the diagnostic chart.
1. If the "misfire" complaint exists at idle only, diagnostic CHART C-4F-1 must be used.
2. A spark tester such as a ST-125 must be used because it is essential to verify adequate available secondary voltage at the spark plug. (25,000 volts). Spark should jump the tester gap on all 6 leads. This simulates a "load" condition.
3. If ignition coils are carbon tracked, the coil tower spark plug wire nipples may be damaged.
4. By switching a normally operating coil into the position of the malfunctioning one, a determination can be made as to fault being the coil or C(3)I module.