Electronic Ignition (EI) System Diagnosis

SYSTEM DESCRIPTION
This system includes the distributor, the Camshaft Position (CMP) sensor, the ignition coil with the Ignition Control (IC) module, the secondary wires, the spark plugs, the Knock Sensors (KS), and the Crankshaft Position (CKP) sensor. The ignition system is controlled by the Powertrain Control Module (PCM). The PCM monitors the information from various engine sensors, computes the desired spark timing, and controls the dwell and firing of the ignition coil via an IC line to the IC module.

DIAGNOSTIC AIDS
Check the following when the distributor rotor does not rotate, while the engine is cranking:
^ A broken distributor drive shaft
^ A worn distributor drive gear or camshaft timing chain and gears

An intermittent may be caused by any of the following conditions:
^ A poor connection
^ Rubbed through wire insulation
^ A broken wire inside the insulation

Thoroughly inspect any circuitry that is suspected of causing the intermittent complaint. Refer to Testing for Intermittent and Poor Connections in Diagrams.

If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Diagrams.

TEST DESCRIPTION

IMPORTANT: The battery should be fully charged prior to any tests.

Steps 1-11:

Steps 12-23:

Steps 24-37:

The numbers below refer to the step numbers on the diagnostic table.
3. This step checks for proper spark output. The spark test 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 operate a spark plug under heavy load.
4. This test separates the distributor cap, rotor, and ignition wires from the ignition coil in order to help identify a secondary ignition system problem.
6. This test checks the ignition control module, connections, and wiring.
12. This test begins to determine if the PCM is providing a signal to the ignition control module. If the PCM is not providing a signal to the ignition control module, the problem exists between the ignition control module and the PCM.
14. This test checks for a basic Engine problem.