Replacing Fuel Pump In '98 Bonneville: Step-By-Step Guide

Replacing the fuel pump in a 1998 Pontiac Bonneville is a complex task. The fuel tank will need to be removed to access the pump, which is held in place by a locking ring. Before beginning, it is important to disconnect the battery and ensure the fuel tank is empty. It is also recommended to relieve the fuel system pressure and disconnect the battery before starting. The fuel pump relay and fuse should be checked, and the fuel filter may need to be replaced. The fuel pump relay is located in the I/P junction block under the passenger side of the dashboard. The fuel pump is accessed through the trunk, but it may be necessary to remove the back seat for easier access. The locking ring that holds the fuel pump in place can be challenging to remove due to corrosion, and a specialty tool can be used to assist with this. Overall, replacing the fuel pump in a 1998 Pontiac Bonneville requires careful attention to safety and a good understanding of automotive repair procedures.

Dropping the gas tank

Step 1: Prepare the Car

• Park the car on a level surface and engage the parking brake.
• Block the rear wheels to prevent the car from moving.
• Disconnect the negative battery terminal to avoid any accidental sparks.
• If there is a significant amount of fuel in the tank, drain it or siphon it out to reduce the weight and risk of spillage.

Step 2: Access the Gas Tank

• Locate the gas tank under the rear of the vehicle.
• Place a jack or jack stands under the gas tank to support it during the removal process.
• Identify the fuel lines, hoses, and electrical connections attached to the gas tank.
• Carefully detach the fuel lines and hoses using appropriate tools, such as line disconnect tools or wrenches.
• Label or mark the hoses and lines to ensure proper reconnection during reassembly.
• Disconnect the electrical connectors and wiring harness leading to the fuel pump.

Step 3: Lower the Gas Tank

• Locate the straps or brackets securing the gas tank to the vehicle.
• Use a floor jack or a hydraulic jack to support the gas tank as you loosen the straps or brackets.
• Loosen the bolts or clamps holding the straps or brackets in place, being careful not to drop the tank suddenly.
• Slowly lower the gas tank using the jack until it is completely detached from the vehicle.
• Carefully move the gas tank away from the vehicle and place it on a secure surface.

Step 4: Remove the Fuel Pump

• Once the gas tank is lowered and accessible, you can proceed to remove the fuel pump.
• Refer to a repair manual or online resources specific to your vehicle for detailed instructions on fuel pump removal.
• Ensure you have the necessary tools and safety equipment before proceeding.
• Follow the recommended procedures for your vehicle to safely remove the fuel pump from the gas tank.

Note: Working with fuel systems can be dangerous due to the risk of fire, explosion, or fuel leakage. It is essential to take appropriate safety precautions, work in a well-ventilated area, and have a fire extinguisher nearby. If you are uncomfortable or unfamiliar with the process, it is advisable to seek professional assistance.

Locating the fuel pump relay

To locate the fuel pump relay of a 1998 Pontiac Bonneville, follow these steps:

Firstly, the fuel pump relay is located in the I/P junction block under the passenger side of the dash. It is labelled as Relay N in the diagram.

Next, the relay should click on when the key is turned on and then click off 2 seconds later. If the relay clicks, try swapping it with one of the other relays in the panel.

Additionally, you should also check the fuel pump fuse in the same panel. This is located at fuse #6.

If the relay does not click when the key is turned on, you may need to use a test light or voltmeter to check for power on the gray wire at the fuel tank connector. Have someone turn the key on and you should get power for two seconds, as well as when cranking the engine.

If there is no power, there may be a break in the gray wire between the fuel pump relay and the fuel pump.

Bleeding the lines and releasing pressure

Bleeding the fuel lines and releasing pressure is a crucial step when changing the fuel pump on your 1998 Pontiac Bonneville. Here is a detailed, step-by-step guide on how to do it effectively:

Step 1: Locate the Fuel Pump Relay

The fuel pump relay is located in the interior passenger side of the dash, in the I/P junction block. It is labelled as Relay N in the diagram. This relay should be activated when the key is turned on and then deactivated after 2 seconds.

Step 2: Check the Relay

If the fuel pump is not working, try swapping Relay N with one of the other relays in the panel. Also, ensure that the fuel pump fuse (#6) in this panel is functional.

Step 3: Test for Power

At the fuel tank connector, test for power on the gray wire. Have an assistant turn the key to the "On" position, and you should have power for about 2 seconds. You should also have power on this wire while the engine is cranking.

Step 4: Check for Breaks in the Wiring

If there is no power, there is likely a break in the gray wire between the fuel pump relay and the fuel pump. Carefully inspect the connector for any damage or loose connections.

Step 5: Bleed the Brakes

To bleed the brakes, start from the wheel farthest from the master cylinder and work your way closer. Always bleed brakes in the following order: rear wheel, driver's rear, front passenger, and finally, front driver. Ensure that the master cylinder is full at all times.

Step 6: Open the Valve

With the pedal pushed to the floor, open the valve to release air and fluid. Close the valve with the pedal still down. If you release the pedal, it will suck in more air.

Step 7: Repeat as Needed

If the pedal is still soft, repeat the bleeding process for all wheels. Ensure that you have a full fluid reservoir and a helper to keep it full during the process.

Step 8: Check Brake Feel

After bleeding, crank the car and check the feel of the brakes. If the pedal is still soft, bleed the brakes again with the car both running and not running.

Remember, safety should always be a priority when working on your vehicle. Ensure that you have a clear and well-lit workspace and follow all standard safety protocols when working with automotive systems.

Removing the retaining ring

To remove the retaining ring, you will need to first lower the fuel tank. Place the car on blocks and crawl underneath to unhook the inline filter to check for flow. If there is no flow, check for power going back to the plug. If there is no power, you can apply power using a booster pack with grey and a black wire in the plug going to the pump to test if the pump will run. If the pump runs, the plug feeding the pump is good. If not, check the plug for power.

If the pump is not working, you will need to remove the tank. There are two straps holding the tank to the car. Use a floor jack and a board to lower the tank. The strap bolts may be an issue if there is a lot of rust, so clean the tank thoroughly all around the pump and then spin the ring off. This can be difficult, and there are many ways to do it. One way is to use a punch and hammer. Once the tank is dropped, it will be easy to see what needs to be done.

It is important to note that there is often major corrosion around the ring that holds the fuel pump to the tank, so consider soaking the ring area in PB blaster and letting it sit before removing the ring. There is also a specialty tool that can assist with ring removal, which can be purchased or rented. If you choose to use a hammer and screwdriver, be very careful not to create an errant spark. If the clips that hold the ring in place get damaged, it will require fuel tank replacement, which is a major undertaking.

Checking the fuel pump fuse

To check the fuel pump fuse of a 1998 Pontiac Bonneville, you will need to locate the fuse box. The fuse box is located under the LH side of the instrument panel (IP) or dashboard inside the vehicle.

Once you have located the fuse box, you need to identify the fuel pump fuse. The fuel pump fuse is usually labelled and should be located in the same panel as the fuel pump relay. For a 1998 Pontiac Bonneville, the fuel pump relay is labelled 'N' in the diagram and the fuse is located at position #6.

After locating the fuel pump fuse, you will need to check if it is blown or damaged. A blown fuse will typically appear burnt or melted, and may be discoloured. If the fuse is blown, you will need to replace it with a new one of the same type and rating.

In addition to checking the fuse, you should also verify that the fuel pump relay is functioning properly. The relay should click on when the key is turned on and then click off after about two seconds. If the relay does not click, try swapping it with another relay in the panel to see if that resolves the issue.

If the fuse and relay appear to be in good condition, the next step is to check for power at the fuel pump. You can do this by accessing the fuel pump module wiring harness and checking for power on the gray wire when the key is turned on and while cranking the engine. If there is no power on the gray wire, there may be a break in the wiring between the relay and the fuel pump.

Frequently asked questions