S10 Pickup, Sonoma 2000-2004

Relieving Fuel System Pressure


The fuel systems operate under high fuel pressures. It is very important that the pressure be properly relieved prior to servicing the system or any of its components.

A Schrader valve is provided on these fuel systems to conveniently test or release the system pressure. A fuel pressure gauge and adapter will be necessary to connect the gauge to the fitting. Most of the MFI systems utilize a service valve on one end of the fuel rail assembly.

  1. Before servicing the vehicle, refer to the Precautions section.
  3. Disconnect the negative battery cable to assure the prevention of fuel spillage if the ignition switch is accidentally turned ON while a fitting is still detached.
  5. Loosen the fuel filler cap to release the fuel tank pressure.
  7. Be sure the release valve on the fuel gauge is closed, then connect the fuel gauge to the pressure fitting located on the inlet fuel pipe fitting.
    When connecting the gauge to the fitting, be sure to wrap a rag around the fitting to avoid spillage. After repairs, place the rag in an approved container.

  9. Install the bleed hose portion of the fuel gauge assembly into an approved container, then open the gauge release valve and bleed the fuel pressure from the system.
  11. When the gauge is removed, be sure to open the bleed valve and drain all fuel from the gauge assembly.
  13. When fuel service is finished, tighten the fuel filler cap and connect the negative battery cable.