Chart 6D4-4 Secondary Ignition Check

Chart 6D4-4: Part 1 Of 3:

Chart 6D4-4: Part 2 Of 3:

Chart 6D4-4: Part 3 Of 3:

ICM Circuit:

CIRCUIT DESCRIPTION
The Secondary Ignition Check tests for faulty spark plugs, plug wires or Ignition Control Module (ICM)/coils. This chart requires J26792 spark tester (ST-125).

NOTES ON FAULT TREE
1. After performing the power balance test, if one cylinder or non-companion cylinders had no rpm change use Part 1 of 3. If two companion cylinders had no rpm change, use Part 2 of 3. Otherwise use Part 3 of 3.

2. J26792 spark tester (ST-125) presents a more difficult load on the secondary ignition than a normal spark plug. If a miss, stumble or hesitation is being caused by a spark plug not firing, the spark tester should also not fire.

3. The companion spark plug shares the same ignition coil with the spark plug being tested (1-4, 2-5, 6-7, 3-8).

4. A suspected ignition system "miss" may actually be a fuel system problem. Perform Chart 6C-1 Fuel System Check, if it has not yet been performed. Chart 6C-1 Fuel System Check

5. If the no spark condition follows the suspected coil, that coil is faulty. Otherwise, the ignition module is the cause of no spark. This test cold also be performed by substituting a known good coil for the one causing the no spark condition.

6. If the no spark condition follows the suspected coil, that coil is faulty. This test could also be performed by substituting a known good coil for the one causing the no spark condition.