Issues Related to the New Parts:
* Incorrect Installation: The most common reason. Double-check that the new coils are properly seated and connected. Make sure the plug wires are securely attached to both the coils and the spark plugs, and that they're routed correctly to avoid interference or shorts. A single misplaced wire will prevent the engine from firing. Mismatched coils or wires (wrong resistance, etc.) are possible too.
* Faulty New Parts: While less likely, it's possible you received a defective coil or set of wires. This is why it's always smart to buy from reputable suppliers.
* Damaged Coil Boots: Check for cracks or damage on the rubber boots that protect the coil terminals. Even tiny cracks can lead to arcing and prevent a proper spark.
Issues Unrelated to the New Parts:
* Ignition Control Module (ICM): This is a common failure point in older vehicles. The ICM controls the firing sequence of the coils. A bad ICM will prevent sparks altogether or result in misfires.
* Crankshaft Position Sensor (CKP): This sensor tells the ICM when to fire the coils. A faulty CKP sensor will prevent the ignition system from knowing when to create sparks.
* Distributor (if equipped): Some Cavaliers of that era might have a distributor. Problems within it, such as a worn rotor or cap, or a faulty pickup coil inside, could prevent spark. (Check for obvious wear and tear.)
* Ignition Switch: A faulty ignition switch may not be sending power to the ignition system correctly.
* Fuses and Relays: Check the fuses and relays associated with the ignition system. A blown fuse will obviously cut power.
* Wiring Issues: Look for any damaged, corroded, or loose wiring in the ignition system, beyond just the plug wires themselves. A break in the wiring harness leading to the coil or ICM will prevent spark.
* Insufficient Fuel or Air: While this won't directly stop the spark, an engine won't run without both. Check the fuel pump and air filter to ensure the engine is getting enough fuel and air to ignite.
Troubleshooting Steps:
1. Visually inspect everything: Carefully examine all connections, wires, and components for any signs of damage.
2. Retrace your steps: Double and triple-check your installation of the coils and wires.
3. Check for power at the coils: With the ignition on, use a test light or multimeter to verify that power is reaching the ignition coils.
4. Check for spark at the plugs: Use a spark tester to check if each spark plug is receiving a spark. This will pinpoint the source of the problem.
5. Test the ICM (if applicable): This requires more specialized tools and knowledge. A mechanic may be needed for this step.
6. Test the CKP Sensor: This typically requires a scan tool or multimeter.
7. Consider a professional diagnosis: If you're not comfortable troubleshooting electrical systems, taking it to a mechanic is the best option. They have the tools and experience to diagnose the problem efficiently.
By systematically checking these areas, you should be able to identify the reason why you're not getting a spark. Remember safety first – disconnect the battery negative terminal before working on the ignition system.
