* Weak Fuel Pump: Even if you hear a noise, it might not be delivering enough fuel pressure. A fuel pressure gauge is the best way to confirm this. Low pressure prevents proper fuel delivery to the injectors.
* Clogged Fuel Filter: A blocked fuel filter restricts fuel flow, even if the pump is working. This is a relatively inexpensive and easy part to replace.
* Fuel Injectors: They might be clogged, faulty, or not getting the correct signal from the ECU (Engine Control Unit). Testing injector operation requires specialized tools.
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the ECU the engine's rotational position, crucial for timing the spark and fuel injection. A faulty CKP sensor will prevent starting.
* Cam Position Sensor (CMP Sensor): Similar to the CKP sensor but monitors the camshaft. A malfunctioning CMP sensor will cause starting problems.
* Ignition Coil(s): While you say you *have* spark, the spark might be weak or inconsistent. A failing coil will often cause intermittent starting issues.
* Low Compression: If the engine's compression is too low due to worn rings, valves, or head gasket issues, it won't start even with spark and fuel. A compression test is needed here.
Troubleshooting Steps:
1. Check Fuel Pressure: This is the most important first step. Rent or borrow a fuel pressure gauge and check the pressure according to your car's specifications. Low pressure points directly to the fuel pump or filter.
2. Inspect Fuel Filter: Visually inspect the filter for damage or excessive dirt. Replacing it is cheap and easy, and a good preventative measure.
3. Check for Error Codes: If your EF Falcon has an OBD-II port (likely, depending on the year), use a code reader to check for any diagnostic trouble codes (DTCs). These codes can provide valuable clues.
4. Test the CKP and CMP Sensors: These sensors can be tested with a multimeter, but it requires knowing the specific resistance values for your vehicle. A faulty sensor usually results in a stored DTC.
5. Inspect Ignition System: Carefully examine the spark plugs, wires, distributor (if applicable), and ignition coil(s) for damage or wear. Weak spark might not be obvious.
6. Compression Test: If the other checks don't reveal the problem, a compression test will assess the health of your engine's cylinders.
If you're not comfortable working on your car, take it to a qualified mechanic. Diagnosing starting problems can be complex and requires specialized tools and knowledge. The cost of a proper diagnosis will be far less than throwing parts at the problem until you find the culprit.
