Fuel Pump Replacement Kit: Step-By-Step Guide

Fuel pump replacement kits are used to repair old or faulty fuel pumps. Fuel pumps are small electric motors that transfer fuel from the fuel tank to the engine. They are durable but not indestructible, and there are many reasons why they may need to be replaced. This includes general wear and tear, contamination by dirt, moisture, or bad gas, and electrical faults. Fuel pump replacement kits contain all the parts needed to repair an old pump, including new diaphragms, gaskets, seals, and valves. The kits are made from materials intended to be used with today's fuels, including those with alcohol content. It is important to note that fuel is highly flammable, so it is crucial to take the necessary safety precautions when using a fuel pump replacement kit.

Relieve the fuel system pressure

Relieving the fuel system pressure is an important step when working on the fuel pump, fuel injectors, lines, and other related components. This is because the system, especially in fuel-injected models, operates under high pressure even when the engine is shut off. Here are four methods to relieve fuel system pressure safely:

Relieving Pressure with the Fuel Pressure Regulator

• Disconnect the negative battery cable using a wrench to prevent sparks, which could ignite fuel and fuel vapors.
• 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.
• Remove the vacuum hose from the top of the fuel pressure regulator by hand.
• Connect a hand-operated vacuum pump to the top of the pressure regulator.
• Apply about 16 inches Hg of vacuum to the regulator 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 may need to raise the rear of your vehicle using a floor jack and support it on jack stands to access the sending unit/pump assembly.
• If your model has an access door above the tank, either remove the rear seat or the trim on the floor of the trunk. 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, ensure the vehicle is secured on the jack stands before locating 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.
• 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 exact location.
• Remove the fuse with your hand or a pair of pliers, or alternatively, remove the fuel pump relay by hand.
• Start the engine and let it idle until it stalls.
• Disconnect the negative battery cable using a wrench.

Relieving Pressure with the Test-Port Valve

• Disconnect the negative battery cable.
• 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.
• Wrap one or more shop rags around the port valve to catch the squirt of fuel that will come out as you depressurize the system.
• Push the valve in using a small screwdriver until fuel stops pouring through the valve.
• Replace the test-port valve cap.

Remove the fuel tank

Removing the fuel tank is a crucial step in replacing the fuel pump. Here are some detailed instructions to guide you through the process:

Before starting, ensure you have the necessary tools and equipment, including a jack to support the vehicle and a fuel pressure gauge with a bleed-off valve/drain hose. It is also recommended to reduce the amount of fuel in the tank to minimize spillage and make the tank lighter and easier to handle.

The process of removing the fuel tank can vary greatly depending on the vehicle. In some cases, you may need to remove the rear seats to access the fuel pump located in the top of the fuel tank. This method is usually faster, taking less than a couple of hours. Alternatively, you may need to disconnect and remove the entire fuel tank, which can take up to five hours.

If your vehicle requires the removal of the fuel tank, follow these steps:

• Locate the fuel tank and use the jack to support and lower it safely.
• Take note of the fuel line connections and wiring attached to the fuel pump.
• Disconnect all the connections and remove the old pump by turning the large lock nut.
• Carefully lift out the old fuel pump from the tank.

Once the fuel pump is removed, you can proceed to install the new fuel pump by reassembling the fuel system and testing its functionality. Remember to consult your vehicle's service manual or seek guidance from online tutorials for specific instructions tailored to your car model.

It is important to work in a well-ventilated area, preferably outdoors, due to the highly flammable nature of fuel vapors. Always prioritize safety by wearing protective gear, including safety glasses and gloves, to shield yourself from fuel spills and splashes.

Disconnect wiring and hoses

Disconnecting wiring and hoses from your fuel pump can be a challenging task, but with careful preparation and the right tools, it can be done efficiently and safely. Here is a step-by-step guide to help you through the process:

Prepare Your Workspace and Gather Tools:

Before starting, ensure your workspace is well-ventilated to minimise the risk of inhaling harmful fumes. Put on safety gear, including safety glasses, gloves, and appropriate clothing to protect yourself from fuel spills. Gather the necessary tools, such as a fuel line disconnect tool, pliers, wrenches, and a catch pan for any spilled fuel.

Locate the Fuel Pump and Fuel Lines:

Refer to your vehicle's manual or online resources to identify the location of the fuel pump and fuel lines. Typically, the fuel lines are located under the car near the fuel tank or engine compartment. Depressurise the fuel system by removing the fuel pump fuse or relay and running the engine until it stalls. This step is crucial to avoid any accidental fuel spray during the disconnection process.

Identify Clips or Connectors:

Once you have located the fuel lines, identify any clips or connectors holding them in place. Some fuel lines have quick-disconnect fittings, while others may require a wrench to loosen the nuts securing the lines to the fuel pump. Be cautious when working with fuel, as it is highly flammable.

Remove Clips or Connectors:

Using pliers or a specialised tool, carefully remove the clips or connectors. Hold onto the fuel lines to prevent unnecessary tension or damage. Some connectors may have tabs or locks that need to be pressed simultaneously for release. If the connector is stubborn, use a flat-head screwdriver to gently depress the tab while pulling out the connector.

Loosen Fittings and Disconnect Fuel Lines:

With the clips removed, use the appropriate size wrench to loosen the fittings on the fuel pump. Gently pull the fuel lines away from the pump, being aware that some fuel may spill out. Have a rag or container ready to catch any spilled fuel.

Dispose of Spilled Fuel Properly:

Ensure that you properly dispose of any spilled fuel to prevent environmental harm. Do not pour it down the drain or into storm sewers, as it can contaminate water sources. Contact your local waste management authority for guidance on how to safely dispose of the spilled fuel.

By following these steps, you can successfully disconnect the wiring and hoses from your fuel pump, making it ready for replacement or repair. Remember to take your time, work in a safe and well-ventilated area, and always refer to your vehicle's manual or seek professional advice if you are unsure about any steps.

Clean the tank

To clean the tank, the first step is to drain all the fuel from the tank into an approved container. Next, the tank must be removed from the vehicle. The area from which the pump is being removed should be cleaned with a brush. The fuel pump should then be removed from the tank, being careful not to let any residual debris fall into the tank.

A hose should then be inserted into the tank, and a stream of clean, hot water should be poured in. While the water is filling the tank, spray a mild detergent inside. If the opening allows, use a brush to loosen debris from the sides of the tank. Once the tank is full, stop the stream of water and swish the water around to ensure all debris is captured. The dirty water should then be dumped into a pan, capturing any liquids. The inside of the tank should be wiped with a lint-free washcloth.

The final steps are to dry the tank completely with compressed air, and then inspect it for rust or physical damage. If there is any damage, the tank must be repaired or replaced.

Install the new pump

To install the new pump, follow these steps:

First, compare the replacement pump to the old pump assembly to ensure they match. Then, install the new seal ring and new pump assembly into the tank. Use a transmission jack or equivalent to raise the tank so that you can reconnect the fuel hoses, electrical connections, and emissions hoses.

Next, raise the tank into place and reinstall the fuel filler neck, securing it with a clamp. Reinstall the fuel tank straps and torque the mounting bolts to the specification listed in the factory repair manual.

Now, safely remove the jack stands and lower the vehicle. Reconnect the negative battery cable and fill the fuel tank as needed. Finally, start the vehicle and double-check your work, keeping an eye out for any leaks.

It is important to note that this process may vary depending on the specific vehicle and fuel pump replacement kit being used. Always refer to the instructions provided with your kit and consult a professional if you are unsure about any steps.

Frequently asked questions