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Home >> Hyundai >> 2005 >> Elantra GLS, 4D Hatchback, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Fuel System >> DTC Troubleshooting Procedures >> DTC P0300: Random/Multiple Cylinder Misfire Detected >> Fuel System Inspection
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Fuel System Inspection

  1. Check the fuel for excessive water, alcohol, or other contaminants. Replace contaminated fuel as necessary.
  2. Install a fuel pressure gage.
  3. Start engine and let it idle. Inspect fuel pressure with vacuum hose disconnected.

    Test Condition : Ignition "ON" & Engine "ON" at Idle

    Specification : 250~350kPa(2.50~3.50 kg/cm2 , 36~50 psi)

  4. Is fuel pressure within the specified value?

    YES 

    • Check for poor connection between PCM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to VERIFICATION OF VEHICLE REPAIR  procedure.

    NO 

    NOTE:
    1. Check if fuel line pressure decreases when accelerating quickly.
      1. If it does, check fuel pump maximum pressure. If pressure is OK, check fuel line and filter for clogging.
    2. If fuel pressure is lower than specification : Check for fuel line pressure while pinching fuel return hose.
      1. If pressure quickly increases, check pressure regulator.
      2. If pressure gradually increases, check for clogging between fuel pump and pressure regulator. If hose is not clogged, check fuel pump maximum pressure.
    3. If fuel pressure is higher than specification : Is fuel line clogged?
      1. If it is not, replace pressure regulator.
      2. If it is, replace it.