Replacing Fuel Pump In Vt Commodore: Step-By-Step Guide

The Holden Commodore VT fuel pump is an important component that transfers fuel from the tank to the fuel injectors, ensuring the engine runs smoothly. A faulty fuel pump can cause issues such as poor engine performance, reduced fuel economy, and stalling. In this guide, we will cover the steps involved in changing the fuel pump in a VT Commodore, including removing the fuel tank, replacing the pump assembly, and reconnecting the fuel lines. We will also discuss common issues that can lead to fuel pump failure, such as contaminants in the fuel and frequent driving with a low fuel level.

Fuel pump assembly for VT Holden Commodore 3.8L/5.0L & Calais 3.8L

To change the fuel pump in a VT Commodore, you will need to remove the fuel tank from the car. This can be done using a hoist, car ramps, or chassis stands, but a hoist is recommended for ease of access. Before removing the tank, run the car until the fuel light comes on to reduce the weight of the tank. It is also recommended to disconnect the fuel pump relay and battery as a precaution. Once the tank is out of the car, the old fuel pump assembly can be removed, and the new fuel pump can be installed. When putting the new fuel pump assembly in, take care with the quick-connect fittings for the fuel lines. It is also important to check the electrical connections, as these can often burn out and cause issues. Additionally, if you are using a hoist, it is recommended to use a bench or stand under the fuel tank for support.

Now, for the Fuel pump assembly for VT Holden Commodore 3.8L/5.0L and Calais 3.8L. The fuel pump module assembly is an in-tank EFI fuel pump that offers silent operation and cooler running. It provides improved fuel delivery, consistent pressure, and accurate fuel gauge readings. The assembly is designed to fit the Holden Commodore VT Series 1 and 2 with 3.8L or 5.0L engines, as well as the Holden Calais VT Series 1 and 2 with 3.8L engines. It is a direct replacement for the original fuel pump and is ready to install, although professional installation is recommended as no fitting instructions are included. The assembly has a super-strong build quality and comes with a free cheat sheet that provides tips on boosting your car's horsepower.

Replacing the fuel pump relay

To replace the fuel pump relay on a VT Commodore, you will first need to locate the relay. The fuel pump relay is typically located in the engine bay, often in a fuse box or relay panel. Once you have located the fuel pump relay, you can proceed with the following steps:

• Disconnect the battery: Before beginning any work on your car's electrical system, it is always a good idea to disconnect the battery as a safety precaution.
• Remove the old relay: Carefully remove the old fuel pump relay from the fuse box or relay panel. Note that relays are often secured in place with clips or other types of fasteners, so you may need to gently pry it out with a small screwdriver or release the clips. Be sure to note the orientation of the relay before removing it so that you can install the new one correctly.
• Inspect the relay socket: With the relay removed, take a moment to inspect the relay socket for any signs of damage or corrosion. If the socket looks damaged or corroded, it may need to be replaced as well.
• Install the new relay: Take the new fuel pump relay and ensure it is the same type and rating as the one you are replacing. Line it up with the socket, making sure it is oriented correctly, and gently push it into place until it is securely seated.
• Reconnect the battery: Once the new relay is installed, you can reconnect the battery.
• Test the fuel pump: Start the car and listen for the fuel pump to prime. You may need to turn the key to the "on" position without starting the engine to hear the fuel pump running. If the fuel pump is working, you should be able to hear it running for a few seconds.

It is important to note that working on a car's electrical system can be dangerous, so if you are not comfortable performing these steps yourself, it is best to consult a qualified mechanic. Additionally, be sure to refer to your VT Commodore's repair manual for specific information pertaining to your vehicle.

Using a hoist to remove the fuel tank

Firstly, run the car until the fuel light comes on and then a bit more. This is important to avoid the risk of a heavy, full fuel tank dropping unexpectedly when you undo the tank straps. Once the tank is close to empty, locate the fuel pump relay and disconnect it, along with the battery. These precautions are not necessary but are recommended for safety.

Now, use the hoist to raise the car to a comfortable working height. It's important to ensure that the car is securely positioned on the hoist and will not roll or shift during the process. Place a bench or stand under the fuel tank. This will support the tank as you remove it, making the job much more manageable.

Next, locate the fuel tank straps and carefully undo them. With the straps undone, you can now lower the fuel tank. Take your time with this step, and be cautious, as the tank is still a significant weight. Once the tank is lowered, you can begin the process of replacing the fuel pump. Remember to put the old fuel in a safe, sealed container.

After replacing the fuel pump, you can reinstall the fuel tank by reversing the steps above. Secure the tank straps tightly, reattach the battery and fuel pump relay, and fill the tank with fresh fuel. It's a good idea to check for any leaks or issues before starting the engine.

Disconnecting the battery

Locate the Battery: The battery in your VT Commodore is typically located in the engine bay, towards the front of the vehicle. It is usually held in place by a metal bracket and has two terminals, positive (+) and negative (–).

Gather the Necessary Tools: Before you begin, make sure you have the right tools for the job. You will need a basic tool kit, which includes a wrench or socket set to loosen and tighten bolts, as well as a pair of gloves to protect your hands from battery acid.

Loosen the Negative Terminal: Put on your gloves and identify the negative terminal of the battery, which is usually marked with a '-' symbol or a black cover. Using your wrench or socket, loosen the nut that secures the negative battery cable to the terminal. Do not allow the wrench to touch any part of the car's body while doing this, as it may cause a short circuit.

Disconnect the Negative Cable: After loosening the nut, carefully remove the negative cable from the battery terminal. Ensure that the cable does not touch any metal parts of the car to avoid creating a short circuit. Place the cable aside, ensuring it is away from the battery and any metal components.

Secure the Negative Terminal: To prevent accidental contact or short circuits, it is important to cover or secure the negative terminal. You can use a piece of electrical tape or a terminal cover to ensure the terminal is insulated and protected.

Optional – Disconnecting the Positive Terminal: In most cases, it is not necessary to disconnect the positive terminal. However, if you need to remove the battery entirely or for added safety, you may also disconnect the positive cable. Follow the same procedure as for the negative terminal, ensuring you do not allow the positive cable to touch any metal parts during the process.

With these steps, you will have successfully disconnected your VT Commodore's battery, ensuring a safe environment to work on other components, such as the fuel pump. Remember to reconnect the battery properly once your repairs or maintenance are complete, following the same steps in reverse order.

Signs of a failing fuel pump

A fuel pump is an essential part of your car, so it's important to know the warning signs of a failing fuel pump. Here are some detailed and direct instructions on what to look out for:

Warning Signs of a Failing Fuel Pump

A failing fuel pump will cause your car to experience major performance issues, and in some cases, it may not start at all. Here are some signs that your fuel pump is failing:

• The car won't start or struggles to start: If your car is not starting or is having difficulty starting, it could be due to a damaged or clogged fuel pump. If the engine cranks but doesn't start, it may be because fuel isn't reaching the engine.
• The car sputters or dies while driving: If your engine stalls or sputters during your drive, it's likely that your fuel pump is faulty. A low-pressure fuel pump can cause the engine to not get the required fuel and air mixture, leading to combustion issues and power loss. This is more noticeable when accelerating or under stress, such as driving uphill or towing a heavy load.
• Engine surges: A common symptom of a failing fuel pump is an engine surge. This happens when too much fuel is sent to the engine, causing the vehicle to repeatedly speed up and slow down without any input from the driver.
• Whining noise from the fuel tank: If you hear a whining or whirring noise coming from your fuel tank, it could be a sign of trouble. Normally, a fuel pump makes a low, barely audible humming sound. However, if the pitch increases significantly, it indicates a potential problem.
• Lower gas mileage: Poor fuel efficiency is another sign of a bad fuel pump. Worn-out or damaged components can allow excess fuel to enter the engine, resulting in higher fuel consumption and more frequent trips to the gas station.
• Loss of power: If your vehicle loses power when driving uphill, carrying heavy cargo, or accelerating, the fuel pump might be the culprit. The engine requires more fuel to operate under stress, and an inadequate supply of fuel will result in a loss of power.

It's important to note that these symptoms could also be caused by other issues, such as bad fuel, damaged fuel lines, or a clogged fuel filter. Therefore, it's always best to consult a qualified technician for a comprehensive inspection and accurate diagnosis.

Frequently asked questions