Fuel Pressure Relief Low Fuel Pressure Relief LY7/LLT

Tools Required

J 34730-1A Fuel Pressure Gage.

Caution: Refer to Safety Glasses Caution in the Preface section.

Caution: 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.

Caution: 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.
1. Ignition OFF.

Caution: Refer to Battery Disconnect Caution in the Preface section.

2. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.
3. Remove the intake manifold sight shield. Refer to Intake Manifold Sight Shield Replacement



4. Turn the fuel gage assembly valve (3) to the open position.

Note: Wrap a shop towel around the schrader valve (2) when connecting the fuel gage assembly to the fuel pressure inspection valve on the fuel feed pipe to avoid fuel spilling.

Note: Screw on the schrader valve quickly to avoid fuel spillage.

5. Connect the schrader valve (2) to the fuel pressure inspection valve on the fuel feed pipe.
6. Place the bleed hose (4) into an approved container.
7. Open the bleed valve (1) to bleed any pressurized fuel.
8. Close the bleed valve (1) when the fuel pressure has dropped to 0 kPa (psi).

1. Close the fuel gage assembly valve (3).
2. Place the bleed hose (4) into an approved container.
3. Open the bleed valve (1) to bleed any pressurized fuel.
4. Close the bleed valve (1).

Note: Wrap a shop towel around the schrader valve when disconnecting the fuel gage assembly from the fuel pressure inspection valve to avoid fuel spilling.

Note: Unscrew the schrader valve quickly to avoid fuel spillage.

5. Disconnect the schrader valve (2) from the fuel pressure inspection valve on the fuel feed pipe.
6. Remove the fuel gage assembly from the vehicle.
7. Empty any excess fuel from the fuel gauge and hose assembly.
8. Install the intake manifold sight shield. Refer to Intake Manifold Sight Shield Replacement
9. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
10. Inspect for leaks.

Fuel Pressure Relief High Fuel Pressure Relief LLT

Warning: Fuel that flows out at high pressure can cause serious injury to the skin and eyes. ALWAYS depressurize the fuel system before removing components that are under high fuel pressure.

Note: If a scan tool is not available, WAIT at LEAST 2 hours after the engine has been run, before removing the high pressure fuel line.

1. Install a scan tool to the vehicle and command the fuel pump relay OFF, allowing the low pressure fuel pump to shut off.
2. Start the vehicle and allow the engine to idle until the engine stops. The engine will stop in approximately 20-30 seconds.
3. Turn the ignition OFF.
4. Using the scan tool, verify that there is little to no fuel pressure, if there still is fuel pressure repeat step 2.