1. Fuel System Issues:
* Empty Tank: The most obvious! Check your fuel gauge.
* Fuel Pump Failure: The pump might be failing to deliver fuel to the engine. You might hear a humming sound from the fuel pump when you turn the key to the "on" position (but not starting). A mechanic can test the fuel pressure.
* Clogged Fuel Filter: A dirty filter restricts fuel flow. Replacement is relatively inexpensive.
* Fuel Injector Problem: Injectors might be clogged or failing to spray fuel properly. This often requires professional diagnosis and cleaning or replacement.
2. Ignition System Issues:
* Spark Plugs: Worn, fouled, or damaged spark plugs prevent ignition. Check their condition and replace if necessary. This is a relatively easy DIY task.
* Ignition Coils: These deliver high voltage to the spark plugs. A faulty coil can prevent one or more cylinders from firing. Testing requires specialized tools.
* Ignition Control Module (ICM): This controls the ignition system. A failing ICM can cause intermittent or complete starting failure. Professional diagnosis is usually needed.
* Distributor (if equipped): Older vehicles might use a distributor. Issues within the distributor, such as a bad cap or rotor, can prevent sparking.
3. Starting System Issues (Beyond Cranking):
* Weak Battery: A low battery might crank slowly, not providing enough power for the starter motor to fully engage. Test the battery voltage.
* Bad Battery Cables: Corroded or loose battery cables can restrict current flow. Clean and tighten them.
* Starter Motor: While the engine is cranking, a weak or failing starter motor might not provide enough power to turn the engine over quickly enough for it to start.
* Security System: Check if your car has an immobilizer or alarm system that might be preventing the engine from starting.
4. Sensor Problems:
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational position. A faulty CKP will prevent the engine from starting.
* Cam Position Sensor (CMP): Similar to the CKP, a faulty CMP can also prevent starting.
* Mass Airflow Sensor (MAF): While not directly related to starting, a faulty MAF sensor can prevent the engine from running properly *after* it starts.
Troubleshooting Steps:
1. Check the obvious: Fuel level, battery voltage, and battery cable connections.
2. Listen carefully: Does the fuel pump prime when you turn the key? Does the cranking sound weak or strong?
3. Check spark: With the spark plugs removed, ground each one to the engine block and crank the engine. Look for a spark. (Be careful, high voltage!)
4. Get a professional diagnostic: If you're not comfortable troubleshooting electrical components, take your Cavalier to a mechanic. They can use a scan tool to check for diagnostic trouble codes (DTCs) that can pinpoint the problem.
Don't attempt repairs you're not comfortable with. Improper work can lead to further damage. A professional diagnosis is often the quickest and most cost-effective solution.
