Replacing Your Silverado Fuel Pump: Step-By-Step Guide

If your 2008 Chevrolet Silverado is experiencing problems such as poor gas mileage or unexpected stalling, you may need to replace the fuel pump. The fuel pump is located within a module inside the fuel tank and cannot be serviced outside of this module, so you will need to replace the entire module and remove the tank to access it. This is a moderately complicated job that is best performed by a professional mechanic at a dealership service department. However, if you are confident in your abilities, you can attempt to replace the fuel pump yourself by following online guides and videos.

Relieve fuel system pressure

To relieve fuel system pressure in a 2008 Silverado, you can try one of the following methods:

Method 1:

Push the Schrader valve on the fuel rail to release the pressure. However, be aware that this will cause fuel to spill out.

Method 2:

Start the truck and locate the fuel pump fuse. Pulling this fuse will cause the fuel line to run almost empty.

Method 3:

If you don't mind fuel spilling onto the floor, you can simply remove the fuel filter without doing anything beforehand. This is the approach typically taken in repair shops.

Please note that these instructions are for relieving fuel system pressure in preparation for fuel filter replacement and not for fuel pump replacement. The fuel pump in a 2008 Silverado is located inside the fuel tank and can be accessed through an access panel in the passenger compartment or by removing the tank from the vehicle.

Disconnect the negative battery cable

Disconnecting the negative battery cable is a crucial first step when performing any electrical work on your 2008 Chevy Silverado. This step ensures that the electrical system is isolated, preventing any potential short circuits or unexpected activation of electrical components during the fuel pump replacement process. Here is a detailed guide on how to safely disconnect the negative battery cable:

• Locate the Negative Battery Cable: The negative battery cable is typically black and is connected to the negative terminal of the battery, which is usually marked with a "-" symbol or a black cap. It may also be shorter than the positive cable. Before proceeding, ensure that you have correctly identified the negative cable.
• Gather Necessary Tools: You will need a basic set of tools for this task, including a pair of gloves to protect your hands from dirt and any potential electrical hazards. You will also need a wrench or socket of the appropriate size to loosen and tighten the battery terminal clamp.
• Disconnect the Cable: Put on your gloves and locate the clamp that secures the negative battery cable to the battery terminal. Using your wrench or socket, loosen the clamp by turning it in a counter-clockwise direction. Once it is loose enough, carefully remove the cable from the battery terminal. Be mindful not to let the cable fall back into place and touch the terminal.
• Secure the Cable: After the cable is disconnected, it is important to ensure that it does not accidentally come into contact with the battery terminal. You can secure the cable by clipping it to a safe part of the vehicle's body or engine bay using a suitable clamp or zip tie. Make sure it is away from any moving parts and will not cause an obstruction during your work.
• Verify the Disconnection: Before proceeding with the fuel pump replacement, double-check that the negative battery cable is indeed disconnected. Ensure that it is securely fastened away from the battery and cannot accidentally come into contact with the terminal. This step is crucial for your safety and to prevent any potential electrical issues.

Remember, working on a vehicle's electrical system and fuel pump requires caution and a methodical approach. Always refer to the manufacturer's guidelines or consult a qualified mechanic if you are unsure about any steps in the process.

Siphon fuel from the tank

To siphon fuel from the tank of a 2008 Silverado, you can use one of the following methods:

Siphoning by Creating Pressure in the Tank

• Find a gas can or another closed container to siphon the fuel into.
• Find or purchase clear plastic tubing 1 inch (2.5 cm) in diameter. You will need two lengths of tubing, one long enough to reach deep into the fuel tank and another shorter length that will reach just inside the tank.
• Set the gas can on the ground near the opening of the car's fuel tank.
• Feed both tubes into the tank. Push the longer tube well into the tank, keeping the other end in the empty gas can. The end of this tubing needs to be fully submerged in the fuel, so carefully blow into the tube and listen for bubbles to check. Push the shorter tube just a few inches into the tank so that both tubes sit side-by-side.
• Use a rag to create a seal around the tubes. This step helps to increase the air pressure in the tank and displace the fuel through the longer tube into the receptacle.
• Force air into the short tube. Ensure that the end of the longer tube sits in the gas receptacle, then blow air into the shorter tube to increase the air pressure inside the tank. You can blow with your lungs, but be careful not to inhale any fumes, or use a mechanical air pump.
• Monitor the flow of fuel. As you blow into the tank, you should see the fuel move through the longer tube into the gas can. Once the fuel is flowing freely, gravity will do the rest of the work. When you want to stop siphoning, cover the long tube, raise it above the level of fuel in the tank, and remove your thumb.

Using a Siphon Pump

• Purchase a siphon pump, which can be found for as little as $10-$15. These pumps come in various shapes and sizes, but most function by creating suction that pulls liquid from one end of the tubing to the other.
• Place a gas can on the ground beneath the tank and run the tubing from the tank to the can.
• Note the designated end of the tubing that liquid enters and exits, and ensure they are in the correct places. If arranged incorrectly, the pump will push air into the tank instead of drawing out fuel.
• Pump when ready. Hand-operated pumps may require you to push a plunger or squeeze a bulb, while mechanical pumps may only need a flip of a switch.
• When you are near your desired amount of fuel, raise the end of the tubing or the container itself to stop the flow. Any residual fuel in the pump should drain back into the tank.
• Remove the siphon pump from the tank when the tubing is free of excess fuel.

Traditional Mouth Siphoning (Not Advised)

Caution: This method carries a high risk of gasoline poisoning, which can lead to difficulty breathing, irritation, vision loss, stomach pain, vomiting, drowsiness, and other serious symptoms.

• Obtain clear tubing that is 1 inch (2.5 cm) in diameter and a closed gas container. Clear tubing is crucial for this method so you can see the fuel moving through the tube and remove it from your mouth before it reaches your mouth.
• Feed one end of the tubing into the vehicle's fuel tank, deep enough so that it sits below the surface of the fuel.
• Place the free end of the tubing in your mouth and breathe only through your nose. Keep your fingers around the tubing near your mouth so you can quickly crimp it before fuel enters your mouth.
• Suck on the tubing and watch the fuel flow into the tube. Suck with your mouth rather than your lungs to minimize the risk of inhaling vapors.
• When the fuel is about six inches from your mouth, crimp the tubing tightly and remove it from your mouth.
• Check for air bubbles in the tubing. If there are air bubbles, release the crimp and drain the fuel back into the car, then try again.
• Stick the end of the tubing into the gas can and release your crimp. The fuel should begin to flow into the can, and gravity will continue pulling fuel from the tank.
• When you have nearly reached the desired amount of fuel, pull the tubing up and out of the tank to stop the flow and allow the remaining fuel in the tube to drain into the gas can.
• Remove the tubing from the gas container once all the fuel has flowed out.

Remove the EVAP canister

To remove the EVAP canister from a 2008 Silverado, you will need to drop the back of the drive shaft, which requires an 11mm wrench. The canister is clipped onto a metal bracket, which is secured with a threaded stud from the bottom centre, tightened with a nut on top (13mm). Once the nut is removed, the three lines can be removed and the canister snaked out.

It is important to note that the EVAP system is part of the vehicle's emission controls, and removing it could have an impact on performance and fuel efficiency. The EVAP system prevents fuel vapours from escaping, ensuring they are burned in the engine.

If you are removing the EVAP canister to replace it, it is possible to purchase a new one from a dealership or an independent service centre. Dealerships will use top-quality manufacturer-recommended parts, whereas independent centres may use non-official or aftermarket parts, which could impact the performance of the vehicle.

Disconnect fuel supply and return lines

Disconnecting the fuel supply and return lines is a crucial step in replacing the fuel pump of a 2008 Silverado. Here is a detailed, step-by-step guide on how to do this:

First, you will need to relieve the pressure within the fuel system. Open the gas cap on the side of the Silverado, then remove the fuel pump relay from the fuse box. Next, start the engine and let it run until it stalls. Once the engine has stalled, disconnect the negative battery cable.

Now, you can begin to disconnect the fuel lines. Start by pressing the retaining tabs for plastic quick-connect fittings. If you have metal collar fittings, use a fuel line separator tool. Be very careful during this step, as gasoline may still be present in the lines and it is important to avoid any spills.

Once the retaining tabs have been pressed, the fuel supply and return lines should be disconnected from the EVAP canister. To do this, simply disconnect the hoses from the canister and remove the bracket mounting bolt. With the lines disconnected, you can now remove the fuel tank and access the fuel pump module.

It is important to note that working with gasoline and vehicle fuel systems can be dangerous. If you are uncomfortable or unfamiliar with any of these steps, it is recommended that you consult a professional mechanic or seek specialized advice.

Frequently asked questions