Fuel System:
* No Fuel: Check the fuel pump. You might hear it prime when you turn the key (listen near the fuel tank), but if not, it could be faulty. Also check the fuel filter – a clogged filter will prevent fuel from reaching the engine. Low fuel level is also a possibility, though less likely if you've recently filled the tank.
* Fuel Delivery Issues: Even if the pump is working, there could be a problem with the fuel lines (leaks, kinks), fuel pressure regulator, or injectors. A fuel pressure gauge is needed for definitive diagnosis here.
* Bad Fuel: Old or contaminated fuel can prevent the engine from starting.
Ignition System:
* Distributor Issues: A 1992 Wrangler likely uses a distributor. Problems could include:
* Worn or faulty distributor cap and rotor: These components distribute the high voltage to the spark plugs. Inspect them for cracks, corrosion, or wear.
* Bad ignition coil: This provides the high voltage. A failing coil may only provide intermittent or weak spark.
* Worn or fouled spark plugs: Inspect and possibly replace them. Worn plugs or those covered in carbon deposits won't ignite the fuel-air mixture effectively.
* Distributor shaft sensor (or pickup coil): This sensor tells the ignition system when to fire the spark plugs. A failing sensor can cause no start issues.
* Ignition Switch: This could be failing, preventing power from reaching the necessary components.
* Wiring Issues: Look for broken, corroded, or loose wires in the ignition system. This is common in older vehicles due to age and wear.
Other Possibilities:
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer the position of the crankshaft, essential for timing the spark. A faulty CKP sensor will prevent starting.
* Computer Problems (ECU): Though less common, a faulty ECU could prevent the engine from starting.
* Security System (if equipped): An aftermarket or factory security system could be preventing the engine from starting.
Troubleshooting Steps:
1. Check for Spark: The easiest way is to remove a spark plug, ground it to the engine block, and crank the engine. If you see a strong spark, you can rule out most ignition system issues.
2. Check for Fuel: If you suspect a fuel delivery issue, try temporarily bypassing the fuel filter (NOT recommended long-term) to see if that's the problem. A more careful approach is to check the fuel pressure.
3. Listen for the Fuel Pump: Turn the key to the "on" position (without cranking) and listen carefully near the fuel tank for the fuel pump whirring.
4. Inspect the obvious: Look for any loose or disconnected wires, cracked components, or obvious signs of damage.
Important Note: Diagnosing car problems can be tricky. If you're not comfortable working on cars, it's best to take your Jeep to a qualified mechanic. Improper troubleshooting could lead to further damage.
