Replacing Fuel Pump In '99 Chevy Blazer: Step-By-Step Guide

Replacing the fuel pump in a 1999 Chevy Blazer requires removing the fuel tank, which is located at the back of the truck. Before beginning, it's important to relieve the fuel system pressure and disconnect the negative battery cable. Once the fuel tank is removed, the fuel pump can be accessed and replaced. It is recommended to have assistance when performing this task and to ensure all necessary tools and safety precautions are in place.

Disconnect the negative battery cable

Disconnecting the negative battery cable on your 1999 Chevy Blazer is a simple process, but it's important to take the necessary precautions to ensure safety and avoid any damage to your vehicle. Here's a detailed guide on how to do it:

• Turn Off the Ignition: Before you begin, make sure your Blazer's ignition is turned off. Never attempt to disconnect the battery cable while the car is powered on.
• Locate the Car Battery: Open the hood of your Blazer and locate the car battery. It's a large, block-like component typically found near the engine bay's surface. If you're having trouble locating it, refer to your owner's manual for the exact location.
• Identify the Negative Terminal: The negative terminal is marked with a "-" symbol and is usually black in color. It often has a black plastic cap for labeling. Make sure you distinguish it from the positive terminal, which is marked with a "+" sign and is typically red.
• Wear Safety Gear: It is recommended to wear safety gloves and goggles to protect yourself from any potential hazards during the process.
• Loosen the Nut on the Negative Terminal: Using a suitable wrench, loosen the nut on the negative terminal by turning it counterclockwise. You may need to try different socket wrench sizes to find the perfect fit. If your battery has a plastic cap, remove it before loosening the nut.
• Remove the Negative Connector: Once the nut is loosened, carefully remove the negative connector cable from the battery. Ensure that the cable is completely out of the way and doesn't touch the battery again until you're ready to reconnect it.
• Secure the Cable: Push the negative cable aside and ensure it is securely positioned away from the battery. You can use a cable tie or any suitable method to keep it in place temporarily.
• Optional: Disconnect Positive Terminal: If necessary, you can also disconnect the positive terminal by following the same steps. Loosen the nut with a wrench and remove the positive connector. Make sure both cables are securely positioned away from the battery.

Remember to exercise caution during the process, especially when working with electrical components. Once you have completed the necessary repairs or maintenance, you can reconnect the negative battery cable by following these steps in reverse. Ensure that the cable is securely connected to the terminal before tightening the nut.

Relieve the fuel system pressure

To relieve the fuel system pressure of your 1999 Chevy Blazer, follow these steps:

• Disconnect the negative battery cable.
• Loosen the fuel filler cap to relieve tank vapour pressure.
• Connect a fuel pressure gauge (J 34730-1A or its equivalent) to the fuel pressure connection. Wrap a shop towel around the fitting while connecting the gauge to avoid spillage.
• Install a bleed hose into an approved container and open the valve to bleed the system pressure.

Now, the fuel connections are safe for servicing. Remember to drain any remaining fuel in the gauge into an approved container.

Remove the fuel tank

To remove the fuel tank from a 1999 Chevy Blazer, follow these steps:

First, ensure you are working in a well-ventilated area and remove any potential sources of ignition, such as lit cigarettes, to reduce the risk of fire and explosion.

Next, disconnect the negative battery cable. Then, relieve the fuel system pressure. You can do this by removing the fuel cap and waiting a couple of hours, or by using a fuel pressure gauge. If you are using a gauge, wrap a shop towel around the fitting to avoid spillage, and be sure to drain any remaining fuel into an approved container.

Now, you can remove the fuel tank. Begin by raising the vehicle and loosening the filler neck hose clamp at the fuel tank. Disconnect the fuel tank filler neck from the tank, and support the tank with a floor jack and a block of wood. Remove the fuel tank shield, and then carefully remove the tank straps.

Lower the fuel tank slightly, taking care not to damage the plastic fuel sender. Disconnect the fuel and vapor hoses and the electrical connections at the sender. Finally, remove the fuel sender and seal ring, using the appropriate tool. Be sure to discard the old seal ring and replace it with a new one before reinstalling the fuel sender.

Disconnect the fuel lines

Disconnecting the fuel lines is a crucial step in changing the fuel pump of a 1999 Chevy Blazer. Here is a detailed, step-by-step guide on how to safely and effectively complete this task:

Preparation:

Before beginning any work on your Chevy Blazer, it is essential to prioritize safety. Ensure you are wearing appropriate protective gear, including gloves and eye protection. Move the vehicle to a well-ventilated area, ideally outdoors, to prevent the buildup of flammable fumes. Have a fire extinguisher nearby in case of any accidents.

Relieve Fuel System Pressure:

Start by relieving the fuel system pressure. Disconnect the negative battery cable. You can then either wait a couple of hours for the pressure to dissipate or use a fuel pressure gauge to release the pressure. If you opt for the latter, connect the gauge to the fuel pressure connection and wrap a shop towel around the fitting to avoid spillage. Open the valve to bleed the system pressure.

Disconnecting Fuel Lines:

Now, you can proceed to disconnect the fuel lines. First, loosen the fuel filler neck hose clamp at the fuel tank. You may need to raise the vehicle to access this area comfortably. Once the clamp is loose, carefully disconnect the fuel tank filler neck from the fuel tank. Ensure that you have a container ready to catch any fuel that may spill during this process.

Lowering the Fuel Tank:

With the fuel lines disconnected, you can now lower the fuel tank. Place a block of wood or a similar support underneath the tank to hold it in place. Remove the two straps securing the tank and carefully lower it about 8 inches. This will give you access to the fuel lines and sending unit.

Final Disconnecting Steps:

Blow off any dirt or debris from the top of the tank. Then, disconnect the plugs on the sending unit and your fuel lines. Ensure that you do not have any lit cigarettes or open flames nearby during this process.

Once the fuel lines are disconnected, you can proceed to remove the fuel tank and sender assembly. This will grant you access to the fuel pump for replacement. Remember to handle the fuel tank and its components with extreme care to avoid any damage, especially to the plastic fuel sender.

Blow dirt off the top of the tank

Blowing the dirt off the top of the tank is a crucial step when changing the fuel pump of a 1999 Chevy Blazer. Here is a detailed, step-by-step guide on how to effectively complete this task:

Firstly, gather the necessary tools and materials, which include compressed air or a similar tool, such as a blow-off valve, and a cloth or towel. Park your 1999 Chevy Blazer on a level surface and engage the parking brake to ensure the vehicle remains stationary during the process.

Next, locate the fuel tank. The fuel tank of the 1999 Chevy Blazer is positioned directly in the middle of the frame at the back of the truck. Once located, use your compressed air or blow-off valve to blow away any dirt, dust, or debris that may have accumulated on the top of the fuel tank. Ensure that you blow away any dirt from the entire surface of the tank, paying close attention to the areas around the fuel tank cap and the sending unit. It is imperative to remove all dirt and debris to prevent any contamination from entering the fuel system, which could potentially cause issues with the vehicle's performance.

During this process, it is advisable to have a helper or assistant to support you. They can use a cloth or towel to catch any dirt or debris that is blown off the tank, preventing it from falling into the engine bay or other sensitive areas of the vehicle.

Once you are satisfied that all dirt and debris have been thoroughly removed from the top of the fuel tank, you can proceed to the next steps of changing the fuel pump. Remember to work carefully and methodically to ensure the task is completed successfully.

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