* Ignition System Issues (despite the parts replacement): While you replaced parts, there's still a chance of:
* Faulty replacement parts: A new part can be defective. Test the new components individually if possible.
* Incorrect installation: Even a seemingly simple task like installing a distributor cap can be done incorrectly, leading to poor or no spark. Double-check all connections and the distributor's position.
* Wiring issues: Look for broken or corroded wires anywhere in the ignition system, even outside the components you replaced. A damaged wire can short-circuit or prevent current from reaching the plugs.
* Ignition module/coil: These parts are often overlooked. A faulty ignition module or coil will prevent the spark from reaching the plugs, regardless of whether the rest of the system is new.
* Ignition switch: A failing ignition switch might not be sending power correctly to the ignition system.
* Fuel Delivery Problems (despite your assessment): While you *think* the fuel and air are fine, there might be more subtle issues:
* Fuel pump pressure: The pump might be weak even if fuel is reaching the engine. Measure the fuel pressure to verify it's within specifications.
* Fuel injectors: Clogged or malfunctioning injectors can prevent proper fuel atomization and combustion.
* Fuel filter: A clogged fuel filter will restrict fuel flow, even if the pump works.
* Sensor Issues: Various sensors are vital for starting and running a car. Problems with these can cause a no-start condition:
* Crankshaft Position Sensor (CKP): This sensor tells the computer when the engine is turning. A faulty one prevents proper timing.
* Camshaft Position Sensor (CMP): Similar to the CKP sensor, a faulty CMP prevents proper ignition timing.
* Mass Airflow Sensor (MAF): Although you say the air is fine, a faulty MAF sensor might be giving the computer inaccurate readings leading to poor or no spark.
* Computer/ECM Issues: The engine control module (ECM) or computer might have a fault. This often requires a diagnostic scan tool to identify.
Troubleshooting Steps:
1. Verify Spark: The most critical step. Use an inline spark tester on each spark plug wire to confirm a strong spark at each cylinder. If spark is weak or missing, focus on the ignition system components.
2. Check Fuel Pressure: Use a fuel pressure gauge to verify the pump is delivering sufficient pressure.
3. Inspect all wiring: Look for broken, frayed, or corroded wires throughout the ignition and fuel systems.
4. Use a diagnostic scanner: A scan tool will read codes stored in the ECM, providing clues to the problem.
Replacing the timing chain is a serious undertaking. If you are not mechanically inclined, having a qualified mechanic diagnose the problem is highly recommended. It could be a relatively simple fix, but could also indicate a more serious underlying issue that might have caused the initial problem (leading to the timing chain replacement in the first place).
