* Fuel System:
* Clogged fuel filter: A dirty fuel filter restricts fuel flow, preventing the engine from getting enough to stay running.
* Fuel pump failure: The fuel pump might be weak or failing, unable to supply sufficient fuel pressure. This is a common cause of this symptom.
* Low fuel: Seems obvious, but make sure the tank isn't nearly empty.
* Fuel pressure regulator: This component regulates fuel pressure; a faulty one can cause erratic fuel delivery.
* Ignition System:
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational position. A faulty CKP sensor prevents proper ignition timing, leading to immediate shutdowns.
* Cam Position Sensor (CMP): Similar to the CKP, a bad CMP sensor will disrupt timing and cause the engine to stall.
* Ignition coil: A failing ignition coil might provide a spark initially but then fail, leading to engine shutdown.
* Ignition switch: Though less common, a faulty ignition switch could be cutting power prematurely.
* Computer/Electrical System:
* PCM (Powertrain Control Module) issues: The computer controlling the engine could have a fault, causing it to shut down. This often requires diagnostics.
* Bad ground connections: Corrosion or loose ground connections can disrupt power flow to vital components.
* Faulty wiring: Damaged or frayed wires can interrupt power to the engine or its components.
* Other possibilities:
* Security system: Some anti-theft systems can prevent the engine from running if they detect a problem.
* Vacuum leaks: Significant vacuum leaks can starve the engine of air, causing it to stall.
* Transmission issues (less likely): In some rare cases, a transmission problem could cause the engine to shut down immediately.
Troubleshooting Steps:
1. Check the obvious: Ensure you have sufficient fuel.
2. Listen for unusual noises: Unusual clicking, whirring, or grinding noises during cranking can provide clues.
3. Check engine codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored by the PCM. These codes provide valuable hints.
4. Inspect the fuel filter: Visually inspect it for blockage or damage.
5. Check fuses and relays: Check the fuses and relays related to the fuel pump and ignition system.
6. Visual inspection of wiring: Look for any obvious damage to wiring harnesses.
Important Note: Diagnosing this problem accurately requires a bit of automotive knowledge and potentially specialized tools. If you're not comfortable working on your vehicle, it's best to take it to a qualified mechanic for diagnosis and repair. Attempting some of these repairs without proper knowledge can be dangerous.
