Replacing The Fuel Pump In Your 2004 Altima: Step-By-Step Guide

If your 2004 Nissan Altima is acting up, it may be time to change the fuel pump. This job should take between 20 minutes and 1.5 hours and can be done at home. The fuel pump is located under the rear seat, so you'll need to remove the rear seat to access it. Before you begin, make sure your car is on empty to avoid spilling excess fuel.

Removing the rear seat

To remove the rear seat of a 2004 Nissan Altima, start by pulling the two lock rings towards the front of the car to release the seat from the locks. There are two locking mechanisms under the front of the seat. Once the locks are released, pull the rear seat out.

Now you will see the fuel pump cover, which is black and located on the driver's side. It is secured by four 1/4-turn plastic Phillips-head locks. Release these locks and lift the cover.

Disconnect the electrical connection to the pump. Be careful, as there will still be residual pressure in the fuel line. Squeeze the connector lock fitting, which is usually white or clear, and, with a twisting motion, pull the fuel line fitting towards the front of the car. Fuel will pour out, so have something under the vehicle or fuel line to catch or absorb it.

Now that the fuel pump is exposed, you can begin the process of changing it.

Disconnecting the electrical harness

First, locate the electrical harness. It is part of the fuel pump assembly, which is situated under the rear seat of the car. To access it, carefully remove the rear seat by locating and pulling the two tabs at the base of the seat and pulling it up. This will expose the fuel pump cover.

Once you have located the electrical harness, the next step is to carefully disconnect it. Before doing so, it is important to label the harness to ensure proper reconnection during reassembly. The electrical harness will be connected to the fuel pump, so take note of how it is attached. Using the appropriate tools, carefully detach the electrical harness from the fuel pump. Be cautious not to damage any of the components during this process.

After the electrical harness is disconnected, set it aside safely. It is important to keep the work area organized and free of clutter to avoid any mishaps. With the electrical harness disconnected, you can now focus on disconnecting the fuel hoses, which will be the next step in changing the fuel pump.

Remember to take your time and refer to the car's repair manual if needed. Working on a fuel pump can be dangerous due to the volatile nature of gasoline, so caution and attention to detail are crucial. If you are unsure about any steps, it is always best to consult a professional mechanic.

Disconnecting the fuel lines

Before beginning, ensure that you have relieved the fuel system pressure. It is important to work cautiously as the fuel line is under pressure.

First, locate the fuel pump cover, which is found under the rear seat. The rear seat can be removed by pulling on two tabs at the base and then lifting it up. With the seat removed, the fuel pump cover will be visible. The cover is secured by four screws, which need to be removed.

Next, you will need to disconnect the electrical harness and the fuel hoses. There are two fuel hoses: a high-pressure fuel input hose and a low-pressure return hose. Label each hose to avoid confusion during reassembly. Different hose clamps are used on each hose, so take note of their positions. Carefully squeeze the connector lock fitting and, with a twisting motion, pull the fuel line fitting toward the front of the car. Fuel will pour out, so have something underneath to catch or absorb it.

At this point, the fuel pump assembly will be accessible. It consists of the pump cover, cover gasket, electric fuel pump, and strainer. The locking ring, which secures the assembly, should be twisted off easily. If it is difficult to remove, gently tap it with a small hammer to loosen it.

Once the locking ring is removed, carefully lift the fuel pump assembly out of the fuel tank. Be cautious of the two wires connected at the bottom of the pump and the fuel gauge sending unit float, which will need to be manoeuvred around when removing the assembly.

After the fuel pump assembly has been removed, it is important to inspect the sealing gasket. If it is damaged, it should be replaced. This step ensures that the fuel pump and fuel system function properly and do not leak.

In summary, disconnecting the fuel lines in a 2004 Nissan Altima involves removing the rear seat, locating and opening the fuel pump cover, disconnecting the electrical harness and fuel hoses, removing the locking ring, and carefully lifting out the fuel pump assembly. Always exercise caution when working with fuel lines and refer to a qualified mechanic if you are unsure about any steps.

Removing the locking ring

To remove the locking ring, first matchmark the locking ring with the body for installation reference. This is to prevent overtightening of the locking ring. Then, remove the locking ring using a special lock ring tool. If you don't have access to a special lock ring tool, it may be possible to use a large set of locking jaw pliers to loosen the lock ring. However, extreme caution must be used to not damage the plastic ring or strip the plastic threads.

The locking ring should twist off easily. If it is difficult to remove, it can be tapped around gently with a small hammer and a drift.

Once the locking ring is removed, you can access the fuel pump and sending unit. Inspect the sealing gasket and replace it if it is damaged.

When you are ready to install the new fuel pump, install the locking ring by hand and tighten it using the special lock ring tool. You can carefully tap it to the locking position in the same way that you removed it. Again, if you need to, it may be possible to use a large set of locking jaw pliers to tighten the lock ring, but be extremely careful not to damage the plastic ring or strip the threads. Tighten the locking ring until the matchmarks align.

Replacing the fuel pump and sending unit

The fuel pump in a 2004 Nissan Altima is located under the rear bench seat. To replace the fuel pump and sending unit, you will need to remove the rear seat to access the fuel pump cover.

First, make sure your car is on empty, or as close to empty as possible, so that all the gas in the tank has been used. Then, start the car and pull the fuel-related fuse until the car stutters and shuts off.

Now, you can remove the rear seat. There are two tabs at the base of the seat that you pull forward, and then pull the seat up. With the seat removed, you will see the fuel pump cover. It's secured by four screws, which you will need to remove.

At this point, you will be able to access the fuel pump and sending unit. The locking ring should twist off easily, but if it's difficult, you can gently tap it with a small hammer and a drift to loosen it. With the locking ring removed, you can lift out the fuel pump assembly.

The fuel pump assembly includes the pump cover, cover gasket, electric fuel pump, and strainer. Be sure to properly relieve the fuel system pressure before proceeding.

Next, you will need to disconnect the electrical harness and fuel hoses from the assembly. Label these before disconnecting them, so you know where they go when it's time to reassemble. One hose is a high-pressure fuel input hose, and the other is a low-pressure return hose, so be sure to use the correct hose clamps for each when reconnecting them.

With the electrical harness and fuel hoses disconnected, you can now remove the fuel pump and sending unit from the fuel tank. Inspect the sealing gasket and replace it if it's damaged.

To install the new fuel pump and sending unit, follow these steps in reverse. Install the locking ring by hand and tighten it using a special lock ring tool. You can also carefully tap it into place with a small hammer, but be extremely cautious not to damage the plastic ring or strip the threads.

Tighten the locking ring until the match marks align. Then, connect the fuel hoses and electrical harness, making sure to use the proper hose clamps for the high-pressure and low-pressure hoses.

Finally, reinstall the fuel pump cover and the rear seat.

This job should take around 1-1.5 hours, but if you're careful and take your time, it may take a little longer.

Frequently asked questions