1. Fuel Pump and System:
* Fuel Pump Relay: This is a common culprit. Locate the fuel pump relay (consult your owner's manual or online resources for its location) and swap it with a known good relay of the same amperage. If the problem goes away, you've found your issue.
* Fuel Pump itself: If the relay swap doesn't work, the fuel pump might be failing. You'll need to listen for the whirring sound of the pump when you turn the ignition key to the "on" position (but don't crank). A lack of sound indicates a potential pump failure. You can also check fuel pressure using a fuel pressure gauge (this requires specialized tools and some mechanical knowledge). Low or no pressure points to a fuel pump or filter problem.
* Fuel Filter: A clogged fuel filter restricts fuel flow. It's a relatively inexpensive and easy part to replace.
* Fuel Lines/Hoses: Inspect the fuel lines and hoses for cracks, leaks, or kinks that could impede fuel delivery.
2. Fuel Delivery System:
* Inertia Switch: Some Ford Explorers have an inertia switch that cuts fuel flow in the event of a collision. Locate this switch (usually under the dash or in the engine bay) and make sure it's properly reset.
* Fuel Pressure Regulator: A faulty regulator could lead to low fuel pressure. This requires more advanced diagnostics.
3. Crankshaft Position Sensor (CKP Sensor):
While you've stated you have spark, a faulty CKP sensor can sometimes interfere with fuel delivery by preventing the computer from signaling the fuel injectors to activate, even with spark present. This is less likely if you have consistent spark.
4. PCM (Powertrain Control Module)/Computer:
A faulty PCM can prevent fuel injection. This is a less likely cause unless you've experienced other electrical problems. PCM diagnostics require specialized tools.
5. Fuel Injectors:
Although less common to fail all at once, faulty fuel injectors could also prevent fuel delivery. This requires testing with a fuel injector tester or by observing injector operation visually.
Troubleshooting Steps:
1. Listen for the fuel pump: Turn the key to the "on" position (don't crank). You should hear a brief whirring sound from the fuel pump.
2. Check the fuel filter: If it looks dirty or clogged, replace it.
3. Check fuel pressure (if you have a gauge): This is the most definitive way to determine if the fuel pump and system are delivering fuel.
4. Inspect fuel lines and hoses: Look for cracks, leaks, or kinks.
5. Check the inertia switch: Make sure it's reset.
6. Swap the fuel pump relay. This is an easy, cheap test.
Important Note: If you're not comfortable working on your vehicle's fuel system, it's best to take it to a qualified mechanic. Working with fuel systems involves potential fire hazards. Always disconnect the negative battery terminal before starting any work.
