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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Engine Controls And Fuel - 2.8L (LWN) Diesel - Diagnostic Information And Procedures (3 Of 3)) >> Diagnostic Information and Procedures >> Fuel System Diagnosis >> Circuit/System Testing

Circuit/System Testing

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    NOTE:

    It may be necessary to remove engine components for the visual inspections.

  1. Verify the following conditions do not exist :
    • Hoses and lines that are flattening when the engine is running, or have kinks that would restrict the flow of fuel
    • Fuel leaks between the fuel tank and the fuel injection pump
    • NOTE:

      A fuel return line that is leaking, is a good indication there is a restriction in the return system.

    • Fuel leaks in the fuel return lines
    • If any conditions exist 

      Repair or replace as necessary.

    • Go to next step : If no conditions exist 
  2. Ignition OFF, disconnect the fuel supply outlet hose at the fuel filter assembly.
  3. Install the CH-37287-1A  Fuel Pressure Gauge Adapter and attach the CH-48027  Digital Fuel Pressure Gauge.
  4. Ignition ON, verify the fuel pressure is between 414-550 kPa (60-80 PSI).
    • If not within 414-550 kPa (60-80 PSI) 
    1. Ignition OFF.
    2. Reassemble the outlet hose at the fuel filter assembly.
    3. Disconnect the fuel supply inlet hose at the fuel filter assembly.
    4. Install the CH-37287-1A  Fuel Pressure Gauge Adapter and attach the CH-48027  Digital Fuel Pressure Gauge.
    5. Ignition ON, verify the fuel pressure is between 414-550 kPa (60-80 PSI).
      • If not within 414-550 kPa (60-80 PSI), replace the G12 Fuel Pump.
      • If within 414-550 kPa (60-80 PSI), replace the fuel filter.
    • Go to next step : If within 414-550 kPa (60-80 PSI) 
  5. Reassemble the hoses at the fuel filter assembly.
  6. Verify engine cranks and runs smoothly.
    • Go to next step : If engine cranks and runs smoothly 
  7. All OK