1. Verify Spark Strength: Just because you *see* spark doesn't mean it's strong enough. A weak spark won't ignite the fuel reliably. Use an inline spark tester to measure the spark's voltage. A weak or intermittent spark could indicate issues with:
* Ignition Coil: Could be failing or not receiving enough power.
* Ignition Module (or Control Module): This controls the ignition coil. A faulty module won't send the correct signal.
* Worn Distributor Cap and Rotor: Check for cracks, corrosion, or worn contacts. Even a slight gap can affect spark strength.
* Spark Plug Wires: Check for cracks, fraying, or incorrect routing. A broken or poorly connected wire will severely reduce spark.
* Spark Plugs: Check the gap and condition. Fouled or worn plugs won't ignite properly.
2. Fuel Delivery Issues (Despite Rotating Distributor): While the distributor is turning, there might still be problems with fuel delivery:
* Fuel Pump: Even with a seemingly functioning fuel distributor, the pump may be weak, clogged, or not receiving power. Listen for the pump's prime sound when you turn the key to "on" (before cranking).
* Fuel Filter: A clogged fuel filter restricts fuel flow, preventing sufficient fuel delivery to the injectors.
* Fuel Pressure: You'll need a fuel pressure gauge to measure the pressure at the fuel rail. This will confirm if the pump is delivering enough fuel at the correct pressure. Incorrect fuel pressure is a common culprit.
* Fuel Injectors: They could be clogged or failing to open properly, even if the distributor is turning. Though less likely if you have spark.
* Computer/Sensor Issues: The computer controls fuel injection timing and quantity based on various sensor inputs (e.g., crankshaft position sensor, oxygen sensor, etc.). A faulty sensor can provide incorrect data to the computer, leading to improper fuel delivery.
3. Other Potential Problems:
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational position, crucial for ignition timing and fuel injection. A faulty CKP will prevent the engine from starting.
* Cam Position Sensor (CMP): Similar to the CKP, but for the camshaft.
* Low Compression: Low compression in one or more cylinders prevents proper combustion, even with spark and fuel. A compression test is needed to determine this.
Troubleshooting Steps:
1. Start with the easiest checks: Visually inspect the distributor cap, rotor, spark plug wires, and spark plugs.
2. Test spark strength: Use an inline spark tester.
3. Check for fuel pump prime: Listen for the pump when the key is turned to "on."
4. Measure fuel pressure: Use a fuel pressure gauge.
5. Check for error codes: Use an OBD-I scanner (if equipped) to read any diagnostic trouble codes (DTCs).
If you're not comfortable working on your car yourself, take it to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately and efficiently. Remember safety first - disconnect the negative battery cable before working on any electrical components.
