* Compression: Lack of sufficient compression in the cylinders prevents the fuel-air mixture from igniting properly. This could be due to:
* Worn piston rings: Leading to blow-by (loss of compression).
* Burnt valves: Preventing proper sealing of the combustion chamber.
* Head gasket leak: Allowing coolant or combustion gases to escape.
* Crankshaft damage: Affecting the piston's ability to compress.
* Timing: The spark needs to occur at precisely the right moment relative to the piston position. If the timing is off (e.g., due to a broken timing belt, slipped timing chain, or faulty distributor), the engine won't start.
* Crank sensor (or crankshaft position sensor): This sensor tells the engine control unit (ECU) the position of the crankshaft, allowing it to time the spark and fuel injection correctly. A faulty sensor will prevent starting.
* Cam sensor (or camshaft position sensor): Similar to the crank sensor, but for the camshaft. A faulty sensor can cause starting problems.
* ECU (Engine Control Unit): The ECU controls the entire ignition and fuel injection system. A faulty ECU can prevent the engine from starting even if all other components are working.
* Fuel pressure: While you say it's getting fuel, the fuel pressure might be insufficient. A weak fuel pump or clogged fuel filter could be to blame. A fuel pressure gauge is needed to check this.
* Starter motor: While you've got spark and fuel, the starter might not be engaging properly to crank the engine. It could be faulty, have a bad connection, or the battery might be too weak.
* Security system: Some Daewoo models have immobilizers or other security systems that prevent starting if the correct key isn't used or if there's a fault in the system.
Troubleshooting Steps:
1. Check the battery: Ensure the battery is fully charged and the terminals are clean and tight.
2. Listen carefully when you turn the key: Does the starter motor crank the engine? A weak crank indicates a possible starter, battery, or connection problem. A complete lack of cranking points to the battery, starter motor, or ignition switch.
3. Verify spark: Even though you *think* you have spark, double check with a spark tester. Weak spark can be a problem.
4. Check for fuel pressure: You'll need a fuel pressure gauge to check this properly.
5. Listen for unusual noises: Knocking, rattling, or unusual sounds coming from the engine can indicate internal problems.
6. Check for codes: Many modern vehicles have diagnostic trouble codes (DTCs) stored in the ECU. Use an OBD-II scanner to read these codes and diagnose potential issues.
If you're not comfortable working on your car yourself, it's best to take it to a qualified mechanic for diagnosis and repair. Trying to troubleshoot these issues without proper tools and knowledge could lead to further damage.
