1. Fuel System:
* Empty Tank: The most obvious! Check your fuel gauge.
* Fuel Pump: A failing fuel pump might not be delivering fuel to the engine. You might hear a faint whirring sound from the fuel pump when you turn the key to the "on" position (but not cranking). If you don't hear anything, it's a strong suspect.
* Clogged Fuel Filter: A restricted fuel filter prevents adequate fuel flow.
* Fuel Injectors: Faulty injectors might not be spraying fuel into the cylinders. This often requires professional diagnosis.
* Fuel Pressure Regulator: This regulates fuel pressure; a malfunction can lead to insufficient fuel delivery.
2. Ignition System:
* Ignition Coil: This supplies high voltage to the spark plugs. A faulty coil prevents sparking.
* Spark Plugs: Worn, fouled, or damaged spark plugs prevent ignition. Visually inspect them (they'll be very dirty if fouled). Gaps should be correct (check your owner's manual).
* Spark Plug Wires: Cracked or damaged wires can prevent spark from reaching the plugs. Look for visible damage.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational position; a faulty sensor prevents proper spark timing.
* Cam Position Sensor (CMP): Similar to the CKP, but for the camshaft.
* Ignition Switch: Although less common, a failing ignition switch can prevent power from reaching the ignition system.
3. Other Potential Issues:
* Security System: An anti-theft system may be preventing the engine from starting.
* Battery: Though it cranks, a weak battery might not provide enough power for the starter *and* the ignition system. Check the battery voltage.
* Starter: While you say it cranks, a weak starter *could* be contributing to the problem by not supplying enough power even though the engine turns over.
* Alternator: A faulty alternator can't recharge the battery and may eventually prevent starting.
* Computer/PCM (Powertrain Control Module): A faulty PCM can cause all sorts of starting problems. This usually requires professional diagnostics.
Troubleshooting Steps:
1. Check the obvious: Fuel level, battery voltage (use a multimeter), and visually inspect spark plugs and wires.
2. Listen carefully: When turning the key to the "on" position (before cranking), do you hear the fuel pump prime?
3. Check codes: Use an OBD-II scanner to check for diagnostic trouble codes (DTCs). This can pinpoint the problem. Auto parts stores often offer free code reading.
4. Professional help: If you're not comfortable troubleshooting yourself, take it to a mechanic. They have the tools and expertise to diagnose the problem quickly.
This is a complex system, and pinpointing the exact issue without hands-on inspection is difficult. Start with the simpler checks, and if you're not getting anywhere, seek professional assistance. Providing more details about the symptoms (like the sound of the engine cranking, any unusual smells, etc.) would help narrow down the possibilities.
