GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Sonoma Pickup - 2WD 🢒 Body and Accessories 🢒 Wiring Systems 🢒 Fuel System Cleaning

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Relieve the fuel system pressure. Refer to Fuel Pressure Relief .
  3. Drain the fuel tank. Refer to Fuel Tank Draining .
  4. Remove the fuel tank. Refer to Fuel Tank Replacement .
  5. Remove the fuel sender assembly. Refer to Fuel Sender Assembly Replacement .
  6. Inspect the fuel strainer. Replace a contaminated strainer and inspect the fuel pump.
  7. Inspect the fuel pump inlet for dirt and debris. Replace the fuel pump if you find dirt or debris in the fuel pump inlet.

    8. Important: When flushing the fuel tank, handle the fuel and water mixture as a hazardous material. Handle the fuel and water mixture in accordance with all applicable local, state and federal laws and regulations.

  8. Flush the fuel tank with hot water.
  9. Pour the water out of the fuel sender assembly opening.
  10. Rock the tank to be sure that removal of the water from the tank is complete.
  11. Inspect the in-line fuel filter for contamination.
  12. Replace the fuel filter if the filter is plugged. Refer to Fuel Filter Replacement .

    13. Important: Only use oil free compressed air to blow out the fuel pipes.

  13. Clean the fuel pipes by applying air pressure in the opposite direction of the fuel flow.
  14. Install the fuel sender assembly with a new seal into the fuel tank. Refer to Fuel Sender Assembly Replacement .
  15. Install the fuel tank. Refer to Fuel Tank Replacement .
  16. Refill the fuel tank.
  17. Install the fuel filler cap.
  18. Connect the negative battery cable.
  19. Inspect for leaks.
    20. 19.1. Turn ON the ignition for 2 seconds.
    19.2. Turn OFFthe ignition for 10 seconds.
    19.3. Turn ON the ignition.
    19.4. Inspect for fuel leaks.