1. The Simple Stuff First:
* Check the fuel pump relay: This is a common culprit. Locate the relay (check your owner's manual or online forums for the location), pull it out, and swap it with a known good relay of the same amperage. If the problem goes away, you've found your issue.
* Check the fuel pump fuse: Similar to the relay, a blown fuse will kill power to the pump. Check your fuse box for a blown fuse related to the fuel pump.
* Listen for the fuel pump: Turn the ignition key to the "ON" position (don't start the engine). You should hear the fuel pump prime for a few seconds. If you don't hear it, that's a strong indication of a fuel pump problem (or a problem with the relay/fuse, which you've already checked). You might need to listen closely, sometimes it's a quiet whir.
* Check for power at the fuel pump: This requires a multimeter. With the ignition on, check for power at the fuel pump's electrical connector. If no power is present, trace the wiring back to the relay and fuse to see where the circuit is broken. Be cautious of working around fuel systems – disconnect the battery negative terminal to avoid sparks.
2. If the Above Don't Work, It Could Be:
* The Fuel Pump Itself: If you've checked the relay, fuse, and power supply to the pump and it still doesn't work, the pump itself is likely faulty and needs replacement.
* Fuel Pump Inertia Switch: This switch is a safety device that cuts power to the fuel pump in a collision. Check the inertia switch (usually located in the passenger compartment) and reset it if necessary.
* Clogged Fuel Filter: A severely clogged fuel filter can restrict fuel flow to the point where no pressure develops. Replace the fuel filter.
* Fuel Lines: Check the fuel lines for leaks, cracks, or kinks. A broken or severely restricted fuel line can also cause a lack of fuel pressure.
* Fuel Pressure Regulator: Although less common as the primary cause of zero pressure, a faulty fuel pressure regulator can sometimes prevent fuel from reaching the injectors.
Important Considerations:
* Safety: Work in a well-ventilated area. Gasoline is flammable and its fumes are hazardous.
* Professional Help: If you're not comfortable working on your fuel system, take the Bronco to a qualified mechanic. Fuel system repairs can be tricky and require specialized tools.
* Year-Specific Issues: There might be year-specific issues with the 1991 Bronco's fuel system. Consult a repair manual specific to that year and model. Online forums dedicated to Ford Broncos might also offer useful troubleshooting information.
Start with the simplest checks (relay, fuse, listening for the pump) and work your way down the list. Remember safety first!
