Hyundai 31111-1G500 Fuel Pump

Check the fuel tank and listen for the fuel pump when the ignition is on. If there's no sound, inspect the EFI fuse and fuel pump relay. If voltage is present at the fuel pump connector, the pump is faulty. If not, the PCM may be defective. To test fuel pressure, use a fuel pressure gauge and T-fitting. For return-type systems, the pump should run for two seconds when the ignition is on. High pressure indicates a restricted fuel return hose or line. Low pressure suggests a restricted fuel filter or supply hose. A substantial pressure drop after five minutes may indicate a leaking injector or faulty check valve. For returnless systems, low pressure indicates obstructions in the fuel supply hose and line, while high pressure requires replacing the fuel pump/regulator. After testing, relieve the fuel pressure, remove the gauge, and start the engine to check for leaks.