Fixing Fuel Pressure: Replacing The Regulator

Replacing a fuel pressure regulator is a relatively simple task that can be done at home with a few common tools. The fuel pressure regulator controls the amount of fuel pressure delivered to each injector, so a failed regulator can cause issues such as increased fuel pressure and consumption, or insufficient fuel pressure, leading to hard starts or non-starts. Before starting, park in a well-ventilated area away from open flames, then relieve system pressure. You will then need to remove the engine cover and disconnect the negative battery cable. Next, remove the air cleaner assembly from the throttle body injection unit to access the fuel pressure regulator, and unplug the electrical connection from the fuel injector. Unscrew and remove the fuel injector retainer, and move the fuel injector to the side. Finish removing the screws holding the pressure cover in place, then carefully lift the cover. Check the order of the components and replace with the new kit, tightening the mounting bolts once complete. Reinstall the fuse or relay fuel pump and connect the negative battery cable, then check for fuel leaks. Finally, reinstall the air cleaner assembly.

Disconnect the battery

Disconnecting the battery is an important step when changing the fuel pressure regulator. Before you begin, ensure you are wearing protective gloves to shield your hands from any harm.

First, open the vehicle's hood to locate the battery. Identify the ground cable attached to the battery's negative post. This cable is responsible for transmitting power to the fuel pump. Using the appropriate tools, carefully detach the cable from the negative post. It is crucial to follow the instructions provided in the vehicle's owner's manual for safe battery cable removal.

Once the battery is disconnected, you can proceed with the next steps of changing the fuel pressure regulator. Remember to keep the removed cable in a secure place to avoid any accidental connections.

After successfully replacing the fuel pressure regulator, you will need to reconnect the battery. Open the hood again and reattach the ground cable to the negative post of the battery. Ensure a firm connection by tightening the battery clamp.

If you did not use a nine-volt battery saver during the replacement process, you will need to reset various settings in your vehicle, such as those for your radio, electric seats, and electric mirrors.

Relieve system pressure

Relieving the fuel system pressure is important when working on the fuel pump, fuel injectors, lines and other related components. Here are some methods to relieve the pressure:

Relieving Pressure with the Fuel Pressure Regulator

First, disconnect the negative battery cable using a wrench to prevent sparks, which could ignite fuel and fuel vapors. Then, locate the fuel pressure regulator on the fuel rail, which is mounted along the top area of the engine. Ensure the regulator is vacuum operated, and remove the vacuum hose from the top of the fuel pressure regulator with your hand. Next, connect a hand-operated vacuum pump to the top of the pressure regulator and apply about 16 inches Hg of vacuum to push the fuel in the lines back into the fuel tank.

Relieving Pressure with the Fuel Pump Connector

Access the sending unit/fuel pump assembly on top of the fuel tank. Some vehicle models provide an access door to the fuel tank through the floor underneath the rear seat or under the trim in the trunk. For other models, you will need to raise the rear of your vehicle using a floor jack and support it on two jack stands to access the sending unit/pump assembly. If there is an access door above the tank, remove the rear seat or the trim on the floor of the trunk. Then, remove the mounting screws on the fuel tank access door using a Phillips screwdriver or by pulling the butyl tape around the door. If the fuel pump is accessed from underneath, be sure the vehicle is secured on the jack stands. Once you have located the fuel pump assembly, unplug the fuel pump electrical connector on the sending unit/pump assembly. Start the engine and let it idle until it stalls, then turn off the ignition switch and disconnect the negative battery cable.

Relieving Pressure with the Fuel Pump Fuse and Relay

Locate the fuel pump fuse under the dashboard or in the engine compartment, usually on the driver's side of the vehicle. It is typically marked for easy identification, and your owner's manual will provide the location. Remove the fuse with your hand, a pair of pliers, or remove the fuel pump relay with your hand. Start the engine and let it idle until it stalls, then disconnect the negative battery cable using a wrench.

Relieving Pressure with the Ford Inertia Switch

The Ford Inertia Switch is a shut-off switch used in many Ford models to cut off fuel to the system in case of an accident. Search for the switch around the trunk, rear compartment, or under the dashboard, and consult your owner's manual if necessary. Once located, unplug the inertia switch's electrical connector, start the engine, and let it run until it stalls. Finally, disconnect the negative battery cable.

Relieving Pressure with the Test-Port Valve

Disconnect the negative battery cable and search for the Schrader valve on the fuel rail around the top of the engine, if your vehicle is equipped with a fuel injection system. Some models use this valve for test purposes, and it resembles the air valve on a bicycle tire. Unscrew the valve cap if there is one, and wrap a shop rag around the port valve to catch any fuel that may squirt out during depressurisation. Push the valve in using a small screwdriver until fuel stops pouring through, then replace the test-port valve cap.

Remove the air cleaner assembly

To remove the air cleaner assembly, first locate the engine cover and remove it. This will involve taking off any brackets that may be blocking access to the air cleaner assembly. If your engine has a transverse-mounted or overlapping intake, you must remove this before proceeding.

Once you have a clear view of and access to the air cleaner assembly, you can begin to disconnect and remove the various components. Put on your safety glasses and protective clothing, and place a drip pan and towel under the fuel rail to catch any spills.

Using a small flat-tip screwdriver, open the schrader valve or test port on the fuel rail to release the pressure. If there is no test port, you will need to remove the supply fuel hose from the fuel rail using a drip pan and a fuel hose quick-disconnect tool kit.

Next, remove the vacuum line from the air cleaner assembly and take off any mounting hardware that is holding it in place. Now you can lift the air cleaner assembly off the fuel rail.

Before installing the new air cleaner assembly, clean the fuel rail with a lint-free cloth and check the condition of the vacuum hose. If the vacuum hose is cracked or damaged, it should be replaced.

Disconnect the vacuum hose

Disconnecting the vacuum hose is a crucial step in replacing a fuel pressure regulator. This process can vary slightly depending on the make and model of your vehicle, but there are some general steps to follow.

First, ensure that you have relieved the fuel system pressure. This can be done by removing the fuel pump fuse or relay and letting the engine idle until it stalls. Alternatively, if your vehicle has a Schrader valve, you can carefully depress the valve with a screwdriver, ensuring that you cover it with a rag to catch any released fuel.

Once the fuel system pressure has been relieved, you can begin the process of disconnecting the vacuum hose. This hose is connected to the fuel pressure regulator, so you will need to locate it first. The vacuum hose is typically attached to the regulator using a fitting or a clip. In some cases, you may need to use a pair of pliers to remove the clip. Be cautious, as the housing can be prone to damage.

After locating the vacuum hose, carefully pull it off the regulator. It is important to note that some vehicles may have the vacuum hose connected to the engine manifold, so ensure you are disconnecting the correct hose. Once the hose is disconnected, set it aside, and be sure to clean the mating surface on the regulator mounting base.

If you are installing a new fuel pressure regulator, you will need to prepare the new component by lightly coating the O-ring with clean engine oil and placing the new gasket in position. This will ensure a proper seal when you install the new regulator.

Finally, reconnect the vacuum hose to the new fuel pressure regulator, ensuring that all fuel lines are properly tightened.

Check for leaks

Once you have replaced the fuel pressure regulator, it is important to check for leaks. Here is a step-by-step guide:

Part 5 of 6: Check for leaks

Step 1: Reconnect the battery. Open the vehicle’s hood and reconnect the ground cable to the battery’s negative post. Ensure the connection is good by tightening the battery clamp.

Step 2: Remove the wheel chocks. Remove the wheel chocks from the rear wheels and put them aside.

Step 3: Turn the ignition key on. Listen for the fuel pump to activate, then turn off the ignition after the fuel pump stops making noise. You will need to cycle the ignition key on and off 3 to 4 times to ensure the fuel rail is full of fuel and pressurized.

Step 4: Check for leaks. Use a combustible gas detector to check all the connections for any leaks. Also, sniff the air for any fuel odours.

Part 6 of 6: Test drive the vehicle

Step 1: Drive the vehicle around the block. During the test drive, listen for any engine cylinders not firing correctly and feel for any odd vibrations.

Step 2: Check for dashboard warning lights. Monitor the dashboard for the fuel level and for any engine light to appear. If the engine light comes on, further diagnosis of the fuel system may be required. This issue may be due to a possible electrical issue within the fuel system.

If the problem persists, get a certified technician to inspect the fuel pressure regulator and diagnose the problem.

Frequently asked questions