System Diagnosis - Enhanced Ignition

Diagnostic Chart:

Wiring Diagram:

SYSTEM DESCRIPTION

This system includes the Distributor, the Camshaft (CAM) position sensor ignition coil with the ignition coil driver, the secondary wires, spark plugs, the Knock Sensor (KS) sensors and the crank sensors. The ignition system is controlled by the Vehicle Control Module (VCM). The VCM monitors the information from various engine sensors, computes the desired spark timing and controls the dwell and tiring of the ignition coil via an Ignition Control (IC) line to the coil driver.

TEST DESCRIPTION

The numbers below refer to the step numbers in the diagnostic table.

The battery should be fully charged prior to any tests.

1. Perform the OBD system check before proceeding unless it was already performed. In order to disconnect the tachometer lead, it will be necessary to disconnect the gray ignition coil connector from the ignition coil and jumper the B terminal of the harness connector to the B terminal of the ignition coil using a fused jumper and terminal test adapter kit J 35616-A.

2. Checks for proper output from the enhanced ignition system. The spark tester requires a minimum of 25,000 volts to operate. This check can be used in case of an ignition miss, because the system may provide enough voltage to run the engine but not enough to fire a spark plug under heavy load. This test also separates the distributor cap, rotor and ignition wires from the ignition coil in order to help identify a secondary ignition system problem.

3. This step determines it the proper available voltage exists in the primary ignition circuit. Also checks ignition coil and wiring.

4. This check begins to determine if the VCM is providing a signal to the ignition coil driver module or not. If the VCM is not providing a signal to the ignition coil driver module, the problem exists between the distributor and VCM.

5. This test checks the coil driver module, connections and wiring.

6. This test checks the wiring from the VCM to the coil driver module and finally the VCM.