Fuel Pressure Relief: Relief

WARNING: Gasoline or gasoline vapors are highly flammable. A fire could occur if an ignition source is present. Never drain or store gasoline or diesel fuel in an open container, due to the possibility of fire or explosion. Have a dry chemical (Class B) fire extinguisher nearby.

WARNING: Relieve the fuel system pressure before servicing fuel system components in order to reduce the risk of fire and personal injury.
After relieving the system pressure, a small amount of fuel may be released when servicing the fuel lines or connections. In order to reduce the chance of personal injury, cover the regulator and the fuel line fittings with a shop towel before disconnecting. This will catch any fuel that may leak out. Place the towel in an approved container when the disconnection is complete.

WARNING: Refer to Safety Glasses Warning .

Turn the ignition OFF.
Disconnect the negative battery cable in order to avoid possible fuel discharge if an accidental attempt is made to start the engine. Refer to Battery Negative Cable Disconnection and Connection .
Remove the fuel injector sight shield.

Fig 1: Fuel Pressure Test Hose Adapter & Pressure Gage

Courtesy of GENERAL MOTORS CORP.

Connect the AU-453 (1) fuel pressure test hose adapter to the fuel pressure connection. Wrap a shop towel around the fitting while connecting the AU-453 (1) in order to avoid spillage.
Connect the J 34730-1A (2) fuel pressure gage to the AU-453 (1). Wrap a shop towel around the fitting while connecting the gage in order to avoid spillage.
Install the bleed hose into an approved container.
Open the valve in order to bleed the system pressure. Fuel connections are now safe for servicing.
Drain any fuel remaining in the gage into an approved container.
Install the fuel injector sight shield.
Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .