The Most Likely Culprits:
* Fuel Pump: This is often the root of the problem. If it's not working, no fuel is getting to the engine. Here's how to check:
* Listen: With the key in the "on" position, but not starting, listen closely under the vehicle. You should hear the fuel pump humming for a few seconds. If you don't hear it, it's likely the fuel pump itself or a related issue (like a bad relay or blown fuse).
* Check Fuel Pressure: Use a fuel pressure gauge (available at auto parts stores) to measure the pressure at the fuel rail. The pressure should be within the specs listed in your Jeep's owner's manual.
* Fuel Filter: A clogged fuel filter can prevent fuel from reaching the engine. Replace it if it hasn't been done recently.
* Fuel Injectors: If the injectors are clogged or not working properly, fuel won't be delivered to the cylinders.
* Ignition System: Even if there's fuel, a faulty ignition system (spark plugs, wires, distributor, ignition coil) can prevent combustion.
* Computer Issues: The Jeep's computer controls the fuel delivery and ignition. It could be malfunctioning, preventing the engine from starting.
Troubleshooting Steps:
1. Check for Fuel:
* Look for leaks: Inspect the fuel lines and connections for any visible leaks.
* Smell for fuel: If you can smell fuel near the engine, there might be a leak.
* Check the fuel tank: Make sure there is enough gas in the tank.
2. Test the Fuel Pump: As outlined above, listen for the pump or use a fuel pressure gauge.
3. Inspect the Fuel Filter: Replace it if it's dirty or hasn't been changed in a while.
4. Check the Ignition System:
* Spark Plugs: Inspect the spark plugs for wear, fouling, or gaps that are out of spec. Replace them if needed.
* Spark Plug Wires: Make sure the wires are connected properly and in good condition. Check for cracks or wear.
* Distributor (if applicable): Inspect the distributor cap and rotor for cracks, wear, or corrosion. Check the spark plug wires for wear or cracking.
* Ignition Coil: Test the ignition coil with a multimeter to ensure it's functioning properly.
5. Computer Diagnosis:
* OBD-II Scanner: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored in the computer. These codes can point you towards the problem.
* Professional Diagnostic: If you're not comfortable with electrical work, a professional mechanic can perform a more in-depth diagnosis.
Safety First:
* Be aware of the dangers of working with fuel. Do not smoke or work near open flames.
* If you're not comfortable with automotive work, seek professional help.
Important Note: Without more information about your specific Jeep and the symptoms you're experiencing, it's impossible to give a definitive diagnosis.
