Replacing Fuel Pump: Step-By-Step Guide For Diy Mechanics

Replacing a fuel pump can be a challenging task, but with careful preparation and a methodical approach, it is possible to do it yourself. Before starting, ensure you have all the necessary tools and safety equipment, including gloves and safety glasses, and choose a well-ventilated workspace to minimise the risk of inhaling harmful fumes. Next, relieve the fuel system pressure and locate the fuel tank, which may involve jacking up the vehicle and removing the fuel tank. Once the fuel tank is accessible, carefully disconnect the wiring connections, fuel lines, and vent hoses before removing the old fuel pump. When installing the new fuel pump, simply reverse the removal process, taking care to clean the area around the pump and check that all connections are secure. Finally, test the new fuel pump to ensure it is functioning correctly.

Relieve the fuel system pressure

To relieve the fuel system pressure, you can try the following methods:

• Run the engine and then pull the fuel pump relay while the engine is on. The engine will stall as a result.
• With the engine off, press the Schrader valve on the pressure line momentarily, capturing the small fuel spray that comes out.
• Drain your fuel tank. Run the vehicle for about 20 seconds. This equalizes the amount of fuel in the siphon unit.

It is important to relieve the fuel system pressure before replacing the fuel pump to avoid spillage and other messiness.

Locate and remove the fuel tank

To locate and remove the fuel tank, you will need to follow these steps:

First, ensure you have the necessary tools and a clear, well-ventilated workspace. You will need items such as wrenches, screwdrivers, a jack, and a fire extinguisher. It is also important to relieve the fuel system pressure before beginning any work. This can be done by running the engine and pulling the fuel pump relay.

Next, locate the fuel tank and place the vehicle on a flat surface, preferably a concrete driveway. Chock the front wheels to prevent the car from rolling while you work. Then, raise the vehicle with a jack to access the brackets or straps securing the tank.

Once the car is lifted, you can begin to disconnect the fuel tank wiring harness and ground wire (if applicable) from the vehicle's harness connector. Remove the fuel lines, filler and vent pipes, and unhook the filler neck. Be sure to keep track of the fuel line connections and wiring before removing the old pump.

Now, locate the fastening system holding the fuel tank in place. This is usually in the form of straps or support frames with bolts. Loosen these bolts until the tank is supported by only a few threads. Carefully lower the fuel tank to the ground as you finish loosening the bolts. Remove any support straps or frames that may interfere with moving the tank.

Finally, remove the tank from underneath the car by dragging it out sideways. Be extremely careful during this process, as fuel tanks can be heavy and difficult to handle, even when drained.

Remember to always put safety first. Wear safety glasses and gloves, and ensure you have the necessary tools and knowledge before attempting any repairs.

Remove the old fuel pump

To remove the old fuel pump, start by relieving the fuel system pressure. This can be done by running the engine and pulling the fuel pump relay, causing the engine to stall. Alternatively, with the engine off, you can press the Schrader valve on the pressure line momentarily to release the fuel spray.

Next, locate the fuel tank and, if necessary, remove it from the vehicle. This process varies depending on the vehicle, and you may need to use a jack to support and lower the tank. In some cases, you may be able to access the pump through an access port located under the rear seat or in the trunk area.

Before removing the old pump, take note of the fuel line connections and wiring. Disconnect all the connections, turn the large lock nut to free the old pump, and then carefully pull it out. Be sure to have a fire extinguisher on hand in case of any spills or leaks.

Once the old pump is removed, you can prepare to install the new pump by cleaning the area and transferring any necessary parts from the old unit. Remember to reverse the procedure when reassembling the fuel system.

It is important to work in a well-ventilated area and to take the proper safety precautions, such as wearing safety glasses and gloves, and disconnecting the battery.

Install the new fuel pump

Installing a new fuel pump is a complex and lengthy process, so it is recommended to hire a professional to install or replace this component. However, if you have the know-how and want to install a new fuel pump yourself, here is a step-by-step guide:

Firstly, ensure you have a reason to replace the fuel pump, such as a no-start issue or a noisy pump. If you have a no-start problem, switch the key on without starting the engine and listen for the fuel pump to run for a couple of seconds. If the pump is running, check the pressure, and if the pressure is good, check the fuel quality.

Next, park your vehicle on a flat surface away from traffic. Disconnect the negative battery cable and relieve the fuel system pressure. Siphon fuel from the tank if it is full, and disconnect the filler tube hose, EVAP system connections, and wires and fuel line connections from the pump.

Now, you can remove the fuel tank. Lower the tank and release the top-mounted fuel lines or electrical connectors. Continue to remove the tank and expose the fuel pump retainer ring. Use an aerosol cleaner to remove dirt and debris from the area to keep the inside of the fuel tank clean.

Before installing the new fuel pump, use a flashlight to inspect the fuel inside the tank for excessive contaminants. It is normal to have some dirt and foreign objects, but excess particles or bad/rotten fuel will cause the new pump to fail.

Match the old pump to the new unit. Install the gas-level float arm and a new primary fuel filter (strainer on the pump). Clean mounting and seal surfaces using a shop towel and carburettor cleaner to ensure a proper seal.

Install the new O-ring gasket/seal before installing the new pump assembly. Gently lower the replacement pump into the fuel tank, taking note of the fuel-level sender orientation. Reinstall the mounting ring or bolts, tightening them to factory specifications.

Finally, complete the job by reinstalling the tank and reversing the previous steps. Add fuel before turning the key on so the pump does not start dry. If your car has a secondary fuel filter, it should also be changed.

It is important to note that fuel is flammable, so this task can be dangerous. If you decide to tackle the job yourself, make sure to take the necessary precautions and have a fire extinguisher on hand.

Reassemble the fuel system

Now that you've removed the old fuel pump, it's time to reassemble the fuel system. This process will involve carefully reconnecting various components and ensuring everything is functioning properly. Here's a detailed guide on how to do it:

Start by installing the new fuel pump into the fuel tank. Refer to your vehicle's service manual for specific instructions on how to secure the pump in place. It's important to follow the steps in the correct order to avoid any issues. Make sure to attach the new gasket or seal to the top plate of the fuel pump to prevent leaks.

Reconnect the wiring harness to the new fuel pump, ensuring all connectors are clean and tight. You can use dielectric grease on the connectors to keep out moisture and prevent corrosion. This will help maintain the longevity of the electrical connections.

Next, reconnect the EVAP system vapor hoses to the fuel tank, as well as the fuel line to the fuel pump outlet. Ensure that all hoses are correctly routed and secured with appropriate clamps. Double-check that there are no leaks at the connections.

Now, carefully raise the fuel tank back into its original position in the vehicle. Secure the tank in place with the support straps. Reinstall the fuel filler hose to the fuel tank inlet and tighten all clamps.

Add several gallons of fuel to the tank. It is recommended that the tank be at least one-quarter full to provide sufficient fuel for proper lubrication and cooling of the fuel pump before starting the engine.

Install a new fuel filter in the fuel supply line. Do not reuse the old in-line fuel filter as it may restrict fuel flow to the engine. A clean fuel filter is essential for optimal fuel pump performance.

Finally, start the engine and carefully inspect all fuel line connections for any signs of leaks. If there are no leaks, you have successfully replaced the fuel pump and reassembled the fuel system. Test-drive the vehicle to ensure everything is functioning as expected.

Remember to consult your vehicle's service manual for specific instructions related to your car's make and model. Taking your time and following the correct procedures will ensure a safe and effective reassembly of the fuel system.

Frequently asked questions