LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1362 (Engine Controls And Fuel - 6.6L - Troubleshooting & Diagnosis) >> Fuel System Diagnosis - High Pressure Side >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: If you were not referred to this test from another diagnostic, do not perform this procedure. Only perform this test when the fuel is more than 18°C (65°F).
IMPORTANT: Before replacing the fuel pressure relief valve, ensure that the break-away torque is within specifications. Refer to Fastener Tightening Specifications .
  1. Remove the fuel pressure relief valve return hose and plug the hose to prevent fuel leakage.
  2. Install a section of rubber fuel hose on the fuel pressure relief valve connection and place loose end of hose into a clean fuel container.
      IMPORTANT: Fuel that is contaminated with gasoline may cause permanent damage to the fuel pressure relief valve. Refer to Contaminants-in-Fuel Diagnosis .
    • If the engine cranks but does not start, crank engine for 15 seconds. Observe for fuel leaking from fuel pressure relief valve.
    • If the engine starts and runs, idle the engine while commanding the fuel rail pressure to 180 MPa with a scan tool. Observe for fuel leaking from fuel pressure relief valve.
    3. IMPORTANT: Always replace the fuel return hose retaining clips on the fuel injectors with new clips after removing.
  3. Remove the fuel return hose from the fuel injectors of the right cylinder bank. Refer to Fuel Injection Fuel Return Pipe Replacement - Right Side .
  4. Connect the yellow hoses from the J 45873  to the J-45873-30  . See Special Tools .
  5. Connect the J-45873-30  with yellow hoses to each fuel injector return port of the right cylinder bank, and install the retaining clips. See Special Tools .
  6. Install the 4 yellow hoses in the J 45873  graduated cylinders in numerical order. See Special Tools .
  7. Connect the fuel return hoses to the J-45873-30  to prevent leakage. See Special Tools .
    • If the engine starts and runs, idle the engine until fuel start dripping into all the graduated cylinders and yellow hoses are full of fuel.
      • IMPORTANT: The engine cranking speed must be more than 150 RPM during the cranking portion of this test.
    • If the engine does not start, crank the engine in 15-second intervals, with 1 minute cooling time between intervals, until fuel starts to flow into all of the graduated cylinders.
  8. Elevate the 4 yellow hoses to retain the fuel in the hoses, and empty the 4 graduated cylinders into a suitable container.
  9. Install the 4 yellow hoses in the J 45873  graduated cylinders in numerical order. See Special Tools .
    • If the engine starts and runs, idle the engine for 15 seconds.
    • If the engine does not start, crank the engine for 15 seconds.
    10. IMPORTANT: During replacement of the injectors, inspect the inlet and outlet fittings for corrosion or contamination. Refer to Contaminants-in-Fuel Diagnosis .
  10. Measure the quantity of fuel in each of the graduated cylinders. Refer to Fuel System Specifications for the desired quantities.
    • If high return flows were recorded, replace those fuel injectors that had high return flow and retest the fuel return flow, referring to Fuel System Specifications . Replace any additional high return flow injectors and proceed to the next number step.
  11. Install and connect all fuel system components that were previously removed or disconnected.
  12. Remove the fuel return pipes from the fuel injectors of the left cylinder bank and repeat the fuel return flow test previously preformed on the right cylinder bank.
    • If high return flows were recorded, replace those fuel injectors that had high return flow and retest the fuel return flow, referring to Fuel System Specifications . Replace any additional high return flow injectors and proceed to the next number step.
  13. Install and connect all fuel system components that were previously removed or disconnected.
  14. Start and idle the engine. You may have to prime the fuel system before the engine will start. Command the fuel pressure control to 180 MPa with a scan tool. The actual fuel pressure should be the same as the commanded pressure.
    • If the engine does not start or the fuel pressure is less than 145 MPa when commanded, replace the fuel injection pump.
  15. Command the fuel pressure control to 180 MPa with a scan tool. The fuel pressure should be able to reach 145 MPa when commanded.
  16. Operate the vehicle in order to verify the repairs.
scientia non olet · About LEMON Manuals