* Ignition Control Module (ICM): The ICM is the brain of the distributorless ignition system. It's likely the most common cause of no-spark issues in these vehicles. A faulty ICM can produce intermittent or no spark, even if the other components are fine. It's crucial to check the ICM for proper operation.
* Cranking Sensor (or Cam Position Sensor): The cranking sensor (or cam position sensor, depending on the specific year and configuration) tells the ICM when to fire the ignition coils. A faulty sensor will prevent the ICM from generating the spark signal. These sensors can be prone to failure over time.
* Ignition Coils: The coils themselves might be bad or have faulty connections. Check the connections to each coil, and consider testing the coils with a multimeter or a dedicated coil tester. A bad coil will prevent spark to a specific cylinder or multiple cylinders.
* Power and Ground Connections: Ensure that the ICM and coils are receiving proper power and ground. Loose, corroded, or broken connections can disrupt the system. Check all fuses related to the ignition system as well.
* Wiring Harness: A damaged wire in the ignition system's wiring harness could be causing intermittent or complete loss of spark. This is harder to diagnose and often requires careful inspection of the harness.
* ECM (Engine Control Module): While less likely, a faulty ECM can also prevent the ignition system from functioning correctly. It's generally harder to diagnose than the other components.
Troubleshooting Steps:
1. Verify Power and Ground: Check for 12V power and a good ground at the ICM and coils.
2. Check Cranking Sensor (or Cam Position Sensor): Inspect for damage and test its output signal (this usually requires a multimeter or a scan tool).
3. Test the Ignition Coils: Check the resistance of each coil using a multimeter. Comparison to factory specifications is crucial.
4. Inspect the ICM: Visually inspect the ICM for any signs of damage. While testing the ICM directly is more complex, you can often find troubleshooting guides specific to this model online.
5. Check the wiring harness: Carefully examine the wiring for any damage, breaks, or corrosion, especially near the ICM and coils.
Replacing the modulator plugs and wires should not have directly influenced the ignition system's ability to create spark, therefore the problem is elsewhere within these components. Systematically go through the troubleshooting steps above to isolate the problem. A scan tool capable of reading codes from the ECM could also provide helpful diagnostic information.
