Repair 7

How to Remove Pressure From the Fuel System for Replacing the Fuel Pump

The fuel system pressurizes fuel from the fuel tank to the engine. Fuel-injection systems meter the fuel injected for the cylinders by controlling the length of time the injectors are open. To inject the correct amount of fuel, the pressure must be constant. The fuel pump contains a check valve to ensure a rapid start next time the vehicle is started by maintaining fuel pressure throughout the system. Depressurize the fuel system to prevent spraying highly flammable gasoline before replacing fuel system components such as a fuel pump.

Instructions

Stall Method

1

Place the vehicle in park. Set the parking brake to prevent vehicle movement. Open the hood.

2

Open the gas filler door. Remove the gas cap to relieve fuel vapor pressure from the fuel tank.

3

Locate the fuel pump fuse. Generally, the fuel pump fuse is located in the underhood electrical distribution center near the battery. Remove the plastic cover protecting the distribution center. The fuse location should be labeled on a diagram on the plastic cover.

4

Start the vehicle and allow the engine to idle. Remove the fuel pump fuse. The engine will run normally for several seconds. The engine will start to hesitate and misfire. Allow the engine to stall.

5

Turn the ignition key off. Disconnect the negative battery cable with a metric wrench to prevent accidental re-pressurization of the fuel system.

Fuel Gauge and Test Port Method

6

Park the vehicle. Engage the parking brake to prevent accidental vehicle movement. Open the hood. Disconnect the negative battery cable with a metric wrench. Open the fuel filler door. Open the gas cap to relieve pressure inside the gas tank.

7

Locate the fuel pressure test port. The test port has a screw on protective dust cap and looks almost exactly like a tire valve stem. Remove the protective dust cap by hand.

8

Place a rag around the fuel test port to catch fuel leakage. Screw the fuel pressure gauge onto the fuel pressure test port.

9

Place the end of the clear plastic line of the fuel pressure gauge into a gas can. Depress the pressure relief button on the fuel gauge to bleed the fuel system pressure into the gas can. Release the valve. The fuel pressure gauge needle should register zero.

10

Remove the fuel pressure gauge and reinstall the dust cap on the fuel pressure test port.