Chart 3 of 3

Diagnostic Chart:

Engine Cranks But Won't Start:

This chart will isolate possible faults that occur with ignition system. Whenever the engine is cranking as indicated by sensor pulses, the ECM will send pulses to the IC module. The ECM pulses (0-5V) to control the charge time (dwell) and spark timing for each ignition event. Each cylinder is controlled separately. An engine may or may not start on less than six cylinders.

TEST DESCRIPTIONS
1. Since each coil is controlled separately it is important to test for spark from each coil. If spark is available on all cylinders, the ignition system is ok. Use ignition coil #1-6 test under engine controls special functions to check. Before running this test, it is imperative to remove the 15A fuel pump fuse from the UHFB and crank the engine for 5 seconds. The fuel system should be checked at this point. Also spark plugs could be fouled.
2. Spark on one cylinder in each IC module indicates that power and ground are ok to that module.