Assuming you have a different car (perhaps you misremembered the year or make/model), a fuel pump not coming on can have several causes:
* Blown Fuse: Check the fuses related to the fuel pump in your car's fuse box. Your owner's manual will show you the fuse layout and which fuse protects the fuel pump.
* Relay Failure: The fuel pump is often controlled by a relay. A faulty relay will prevent power from reaching the pump. Try swapping the fuel pump relay with a known good relay of the same amperage and type (relays are usually easily identifiable in the fuse box).
* Fuel Pump Failure: The pump itself could have failed. This is a common issue as fuel pumps wear out over time.
* Wiring Issues: Damaged or corroded wiring between the fuel pump, relay, and computer can interrupt the power supply. Inspect the wiring harness for any visible damage.
* Computer Problem: The car's computer (PCM or ECM) may have a fault that's preventing it from sending the signal to activate the fuel pump. A scan tool can help diagnose this.
* Inertia Switch: Some cars have an inertia switch that cuts power to the fuel pump in case of a collision. Check if there is such a switch and if it's tripped (usually a red button that needs to be pressed).
* Low Fuel Level: In some vehicles, the fuel pump will not activate if the fuel level is extremely low. Though less likely in a newer vehicle, it's worth checking if the tank is almost empty.
To diagnose the problem:
1. Check the fuses and relay.
2. Listen for the fuel pump prime: Turn the ignition key to the "on" position (without starting the engine). You should hear a brief humming sound from the fuel pump in the fuel tank. If you don't hear it, the problem is likely before the pump.
3. Use a test light or multimeter: You can use these tools to check for power at the fuel pump and relay to pinpoint where the circuit is broken.
4. Consult a repair manual: A repair manual specific to your car's year, make, and model will provide detailed diagrams and troubleshooting steps.
5. Use an OBD-II scanner: A scan tool can read diagnostic trouble codes (DTCs) from the car's computer, which might indicate the cause of the problem.
If you can provide the correct year, make, and model of your car, I can provide more specific advice. Attempting repairs on a fuel system can be dangerous due to the potential for fire or explosion. If you're not comfortable working on your car's fuel system, take it to a qualified mechanic.
