Relieving Fuel Pressure

TOOLS REQUIRED: 

• 7000081-SAT3 Tech-2
• SA9127E Gauge Bar Set

Prior to servicing any fuel system components (fuel rail, injectors, filter/pressure regulator, fuel tank, fuel pump module, etc.) any pressure built up in the system must be relieved. There are two  preferred methods:

1. Start and run the vehicle, then disable the fuel pump with Tech-2 7000081-SAT3.

   This method is the cleanest since no fuel under pressure will be present at any fitting or connection that needs to be serviced.

   This method is preferred when removing any components of the fuel system that require disconnecting fuel lines. If performance tests are to be run on the system underhood, procedure 2 will be preferable since the gauge bar (53476) will also be required for the testing.

   This method is also preferable to disconnecting the fuel pump relay since no DTCs will be set and there is no concern about voltage spikes to the PCM if the relay should be re-installed with the key On.

   1. Connect Scan tool and start vehicle.
   2. Turn Scan tool On and locate SPECIAL TESTS.
   3. Select PCM/EC, then select FUEL DELIVERY.
   4. Select FUEL PUMP, then command fuel pump Off.
   5. Engine will die in 3-5 seconds. Turn key Off, and proceed with component removal/installation.
      Fig 1: Relieving Fuel Pressure

      Courtesy of GENERAL MOTORS CORP.

2. Bleed pressure at service test port.

   This method will require the collection of fuel as the pressure is relieved. Use of a suitable container is required.

   1. Remove air induction tube.
   2. Locate service test port on fuel supply line at fuel rail and remove protective cap.
   3. Connect the gauge bar (53476) to the fuel pressure adapter (309725) using a flexible hose from the Gauge Bar Set SA9127E.
   4. Make sure that the needle valve on the pressure adapter is closed (OFF).
      NOTE: Do not use any tools to tighten the adapter to the fuel line pressure port. If the adapter will not seal with finger tightening, then the seal is defective or damaged and needs to be replaced. Excessive torque on the adapter will damage the fuel line test port.
   5. Connect the pressure adapter to the fuel line test port.
   6. Route the drain hose from the pressure adapter into a suitable container.
   7. Open the valve on the pressure adapter and bleed off the pressure (and fuel).