Replacing The Fuel Pump In A '99 Grand Prix

Replacing the fuel pump in a 1999 Pontiac Grand Prix can be a complex task. The pump is located inside the fuel tank, so you will need to drain the tank and relieve the fuel system pressure before attempting any repairs. You will also need to disconnect various components, such as the quick-connect fittings at the end of the fuel lines, the electrical harness, and the fuel tank retaining straps. Additionally, you may need to remove the rear seats and carpet to access the fuel tank. It is important to verify that the fuel pump is faulty before attempting any repairs, as the issue could be caused by a clogged fuel filter or a problem with the fuel pump relay.

Check if there is an access panel in the trunk

To check if there is an access panel in the trunk of your 99 Grand Prix, first empty your trunk and reach up by the rear of the back seat. Pull back the floor carpet to see if you have the access panel. If you do, you can access the fuel pump from behind the back seat. You will also need to check if you have the rear seat trunk door.

If you do have an access panel, you will be able to see two electrical connections and three tubes connected to your fuel sending unit. Disconnect the electrical connections and the tubes. You will need to disconnect the hoses from the fuel tank filler, the EVAP vent, and the EVAP vapor pipes.

Drain the fuel tank

To drain the fuel tank of a 1999 Grand Prix, follow these steps:

First, relieve the fuel system pressure. Next, raise and support the vehicle. Disconnect the quick-connect fitting at the fuel filter. Disconnect the quick-connect fittings at the end of the fuel lines. Remove the rubber exhaust hangers, allowing the exhaust system to rest on the rear axle. Remove the exhaust heat shield. Loosen the fuel filler hose clamp at the fuel tank. Remove the hoses from the fuel tank filler, the EVAP vent, and the EVAP vapour pipes.

Now, disconnect the electrical harness from the multi-way rear body connector and fuel strap. With the aid of an assistant, support the fuel tank and disconnect the two fuel tank retaining straps. Lower the fuel tank. Finally, disconnect the wiring harness from the modular fuel sender assembly and the fuel tank pressure sensor.

Disconnect the quick-connect fittings at the end of the fuel lines

Disconnecting the quick-connect fittings at the end of the fuel lines is a crucial step in changing the fuel pump in a 99 Grand Prix. Here is a detailed, step-by-step guide to help you through the process:

Firstly, ensure you have the necessary tools and safety equipment. This includes eye protection and gloves to protect yourself, and a socket wrench that fits the quick-connect fittings. It is also important to relieve the fuel system pressure and drain the fuel tank before beginning any work.

Now, locate the fuel lines. These are the hoses that carry fuel to and from the fuel pump. Once you have found them, you will see the quick-connect fittings at the end of each line. Quick-connect fittings are designed to be easily connected and disconnected without the use of tools, however, a socket wrench may be required if they are tight.

To disconnect the fittings, depress the release collar on the fitting while pulling the fuel line away from it. The release collar is a small, circular tab that secures the fuel line to the fitting. Depressing this tab will release the fuel line, allowing you to disconnect it from the fitting. Be gentle but firm, as fuel lines can be delicate and you don't want to damage the fitting or the line.

If you are having trouble disconnecting the line, you can try wiggling it gently from side to side while pulling. Be careful not to kink or damage the fuel line. If the line is difficult to remove, it may be helpful to apply a small amount of lubricant to the fitting to aid in the disconnection. Once the line is free, set it aside, ensuring it is away from any potential sources of ignition.

Repeat this process for each of the quick-connect fittings at the end of the fuel lines. It is important to ensure that all fuel lines are properly disconnected before proceeding with the next steps of changing the fuel pump.

Remove the fuel pump assembly

To remove the fuel pump assembly from your 1999 Grand Prix, you'll first need to relieve the fuel system pressure and drain the fuel tank until it is a quarter full. Next, disconnect the negative battery cable with a socket wrench. Remove the jack and spare tire so that you can take out the lining in the trunk. Now, open the fuel sender access panel by removing the nuts with a socket wrench.

Remove the electrical connector from the fuel tank pressure sensor and the fuel pump. Disconnect the quick-connect fittings for the fuel pump. Take out the retaining ring for the fuel pump and remove the fuel pump assembly. Finally, discard the old O-ring.

Install the new fuel pump

To install the new fuel pump, first, you will need to get the correct fuel pump for your 99 Grand Prix. This will depend on the engine size. For the 1997 to 2003 models, the engine size is either 3.1 L or 3.8 L.

Once you have the correct pump, you can begin the installation. Start by reconnecting the quick-connect fittings for the fuel pump. Then, install the new retaining ring for the fuel pump and put the new fuel pump assembly into place. Make sure to use the new O-ring that came with the kit.

Now, you can reverse the removal procedure to complete the installation. Tighten the nuts on the access panel to 89 in. lbs. with a torque wrench. Finally, reconnect the negative battery cable with a socket wrench.

Frequently asked questions