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Home >> Kia >> 2004 >> Rio Base, Standard >> Repair and Diagnosis >> Engine Mechanical >> Fuel System >> Fuel System & Fault Isolation >> DTC Troubleshooting >> DTC P0300: Random Multiple Cylinder Misfire Detected >> Inspection/Repair >> System Inspection >> Fuel System Inspection

Fuel System Inspection

  1. Check the fuel for excessive water, alcohol, or other contaminants. Replace contaminated fuel as necessary.
  2. Install a fuel pressure gauge
  3. Start engine and let it idle. Inspect fuel pressure with vacuum hose disconnected.
    1. Test Condition: Ignition "ON" & Engine "ON" at Idle
    2. Specification: 250~350 kPa (2.50~3.50 kg/cm2 , 36~50 psi)
  4. Is fuel pressure within the specification?

    YES

    1. Check for poor connection between ECM 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

    1. Repair as necessary refer to inspection noted as below and go to "VERIFICATION OF VEHICLE REPAIR " procedure
      CAUTION:
      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
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