Replacing Electric Fuel Pumps: A Comprehensive Diy Guide

Replacing an electric fuel pump can be a complex and hazardous task, so it's important to take the necessary precautions and follow the correct procedure. Before attempting any replacement, it is crucial to rule out other potential issues, such as a plugged fuel filter or faulty fuel pump relay. If, however, you have ascertained that the pump is at fault, there are several steps to take. First, relieve the fuel system pressure and disconnect the battery. Next, drain the fuel tank and disconnect the filler tube hose and electrical connections. With the tank supported by a jack, remove any retaining straps and carefully lower the tank. Disconnect the fuel lines and remove the faulty pump. Compare the new pump to the old one to ensure you have the correct replacement, then install it, reconnecting the fuel lines and electrical connections. Finally, refill the tank and test the vehicle for leaks.

Characteristics of Electric Fuel Pump Replacement

Safety precautions

Before attempting to replace an electric fuel pump, there are several safety precautions you should take to ensure your safety and that of your vehicle. Here are some detailed, direct, and instructive guidelines:

Work in a Safe Environment: Ensure you work in a well-ventilated area away from any sources of ignition or open flames. Gasoline is highly flammable, and gasoline fumes can travel long distances and be easily ignited by heaters, pilot lights, electric motors, or even static discharges. Keep any ignition sources away from the vehicle and fuel tank during the replacement process.

Wear Protective Gear: Don safety glasses and gloves to protect your eyes and hands from any spills or splashes of fuel.

Prepare for Spills: Have cleanup materials ready to immediately clean up any fuel spills or leaks. Use absorbent materials, such as rags or paper towels, to soak up spills, and have a suitable container to dispose of the used materials safely.

Relieve Fuel System Pressure: Before starting any work on the fuel system, relieve the fuel system pressure by disconnecting the negative battery cable. This will help reduce the risk of fire or injury.

No Smoking: Do not smoke during the replacement process. Smoking near the fuel system can pose a serious safety hazard due to the flammable nature of gasoline.

Avoid Sparks: Do not use an electric drill-powered pump to drain the fuel tank, as the sparks may ignite the fuel. Also, avoid using incandescent light bulbs or trouble lights near the fuel tank, as the hot surfaces can ignite any spilled or splashed fuel.

Use a Support Jack: When removing and lowering the fuel tank, use a jack and a block of wood to support the tank securely. Do not work under a vehicle that is only supported by a jack. Use jack stands with the proper weight rating to handle the weight of the vehicle.

Store Fuel Properly: When draining the fuel tank, use an approved container such as a gas caddy or gas can to store the fuel. Do not use open buckets or glass/plastic bottles for fuel storage.

Avoid Re-entering Your Vehicle: If you need to start the vehicle during the replacement process, avoid re-entering it while the fuel pump is active. Re-entering the vehicle can create static electricity, which could potentially spark a fire. If you must re-enter the vehicle, discharge any static build-up by touching a metal surface for a second.

Use a Fire Extinguisher: Keep a fire extinguisher nearby in case of any fires or sparks during the replacement process.

Be Careful with Connections: When reconnecting the electrical connectors and fuel lines, ensure all connections are tight and secure. Loose connections can lead to fuel leaks or electrical issues.

Check for Leaks: After completing the replacement, add several gallons of fuel to the tank and check for any leaks. Ensure the tank is at least 1/4 full before starting the vehicle to provide proper fuel pump lubrication and cooling.

Replace the Fuel Filter: Don't forget to replace the fuel filter as well. A new fuel filter will ensure that your new fuel pump runs smoothly and efficiently.

Locating the fuel pump

Mechanical Fuel Pump

If your vehicle has a mechanical fuel pump, it is usually found on the side of the engine.

Electric Fuel Pump

If your vehicle has an electric fuel pump, it is typically located inside the fuel tank. To access the fuel pump, you may need to remove the rear seat to find the fuel pump access door. Alternatively, you may need to drop the fuel tank.

GDI Systems

Vehicles with GDI (gasoline direct injection) systems often have a second, high-pressure pump located near the fuel rail in the engine compartment.

Testing the Fuel Pump

To check if your fuel pump is working, ask an assistant to turn the key to the "on" position while you listen near the gas tank opening. If the pump is working, you should hear a hum for two to three seconds.

Removing the old fuel pump

First, make sure your vehicle is parked on a firm, level surface with the parking brake set. Block the front wheels so the vehicle can't roll, and use jack stands to raise the rear of the vehicle. You will also need to relieve the fuel system pressure and disconnect the negative battery cable.

Next, siphon or drain as much fuel as possible from the fuel tank. This will make the tank much lighter and easier to handle. Remember to drain the fuel into an approved container and seal it once you're done.

Now you can start to remove the fuel tank. Disconnect the filler neck from the tank by loosening or removing the clamp that holds the hose in place. Then, remove the bolts that secure the fuel tank straps to the vehicle, and gently lower one end of the tank. This will allow you to access the wiring connections, fuel lines, and vent hoses on top of the tank. Disconnect these before removing the remaining bolts and lowering the tank completely.

With the tank on the ground, you can now access the fuel pump. Undo the plate that holds the pump in place—this may involve rotating a metal ring counterclockwise or unscrewing some screws or bolts. Once the plate is loosened, carefully pull out the fuel pump.

Before installing the new pump, it is important to inspect the fuel tank and hoses for any signs of damage or dirt. If the filter screen is clogged or the tank is dirty, it will need to be cleaned or replaced.

Installing the new fuel pump

First, you will need to relieve the fuel system pressure and disconnect the negative battery cable. Siphon or drain as much fuel as possible from the fuel tank. Disconnect the filler tube hose and the electrical connection to the pump. Support the fuel tank with a jack and a block of wood. Remove any retaining straps or bolts holding the tank to the frame. Lower the tank.

Disconnect the fuel lines and remove the old fuel pump from the tank. Compare the new fuel pump with the original to verify that you have the correct part.

Now, you can install the new fuel pump. Connect the fuel lines to the pump. Lift the fuel tank up and install the retaining strap. Reconnect the filler tube hose and the electrical connector. Reconnect the negative battery cable.

Finally, fill the tank with gas and conduct a road test to confirm a successful repair.

Testing for leaks

Step 1: Inspect Fuel Lines and Connections

Begin by inspecting the fuel lines and connections near the pump for any visible signs of leakage. Look carefully for any cracks, damage, or dripping fuel.

Step 2: Check for Fuel Spraying or Dripping

With the fuel lines still connected, turn on the ignition and listen for the characteristic humming sound of the fuel pump. If the pump is functioning, you can then turn off the ignition and carefully disconnect the fuel lines, inspecting for any spraying or dripping fuel as you do so.

Step 3: Use a Syringe to Measure Fuel Pressure

If you have access to one, a syringe with milliliters marked on it can be used to measure the fuel pressure. This will help you determine if the pump is delivering the correct amount of fuel.

Step 4: Test Voltage with a Multimeter

Using a multimeter, test the voltage at the electrical connector of the fuel pump. With the ignition on, the voltage should read around 12 volts. If the voltage is lower or non-existent, there may be an issue with the wiring, fuse, or relay.

Step 5: Fill the Tank and Check for Leaks

Once you have reconnected the fuel lines and electrical connectors, fill the tank with fuel and check for leaks. Ensure the tank is at least one-quarter full to provide adequate lubrication and cooling for the fuel pump.

Step 6: Start the Engine and Inspect Connections

Start the engine and carefully inspect all fuel line connections for any signs of leakage. If there are no leaks, your new fuel pump has been successfully installed.

Remember to always exercise caution when working with fuel. Work in a well-ventilated area, keep sparks or open flames away from the fuel system, and always wear protective gear, such as gloves and safety glasses.

Frequently asked questions