2001 Buick Century Fuel Pump Replacement: The Complete Step-by-Step Guide

If you need to replace the fuel pump on your 2001 Buick Century, here is the most important thing to know: The fuel pump is located inside the fuel tank, and the replacement requires dropping the tank from underneath the vehicle. This is a job that many DIYers can handle with the right tools and patience, but it takes several hours of careful work. The fuel pump assembly itself includes the pump, strainer, sending unit, and fuel level sensor, so you should replace the entire assembly rather than just the pump. A failing fuel pump will show clear symptoms before it completely dies, and catching it early saves you from being stranded.

Understanding the 2001 Buick Century Fuel Pump System

The 2001 Buick Century uses an electric fuel pump mounted inside the fuel tank. This pump delivers fuel at a pressure between 40 and 50 PSI to the fuel rail and injectors. The pump is part of a modular fuel sender assembly that also contains the fuel level sensor, pressure regulator, and fuel filter screen. Unlike older vehicles with mechanical pumps mounted on the engine, this design keeps the pump cool by submerging it in fuel, which extends its life. When the pump fails, you must remove the entire assembly from the tank.

Common symptoms of a failing fuel pump on a 2001 Buick Century include:

  1. Engine cranks but will not start – This is the most obvious sign. You hear the starter motor turning the engine over, but the engine never fires up. If you turn the key to the "ON" position, you should hear a faint whirring sound from the rear of the car for about two seconds. That is the fuel pump priming. If you hear nothing, the pump is likely dead.

  2. Sputtering or hesitation during acceleration – A weak pump cannot maintain proper fuel pressure when you step on the gas. The engine may stumble, hesitate, or feel like it is running out of gas even with a full tank.

  3. Loss of power going uphill or on the highway – When the engine needs more fuel, a failing pump simply cannot deliver. You may notice the car struggling to maintain speed, especially on inclines.

  4. Engine surges or bucks at steady speeds – This happens when the pump delivers inconsistent fuel pressure. The engine speed fluctuates up and down without you touching the gas pedal.

  5. Poor fuel economy – A malfunctioning pump forces the engine to run rich or lean, both of which waste fuel.

  6. Check Engine Light comes on – The computer detects low fuel pressure or a lean condition and stores a diagnostic trouble code. Common codes include P0087 (fuel rail pressure too low) or P0171 (system too lean).

Before you assume the fuel pump is bad, check the fuel pump relay and fuse first. The relay is located in the underhood fuse block on the driver's side of the engine compartment. The fuse is also in that same box. A bad relay can mimic a dead pump. If the relay clicks when you turn the key but the pump does not run, check the wiring harness connector at the tank for corrosion or damage.

Tools and Parts You Will Need for the Replacement

Replacing the fuel pump on a 2001 Buick Century requires a specific set of tools. Do not start this job without everything on hand, because you cannot drive the car to get a missing tool.

Tools required:

  • Floor jack and two jack stands (rated for at least 2 tons)
  • Lug wrench to remove the rear wheels
  • Ratchet set with metric sockets (10mm, 13mm, 15mm, 18mm)
  • Flathead screwdriver and Phillips screwdriver
  • Fuel line disconnect tool (3/8 inch and 5/16 inch sizes) – this is mandatory, do not try to pry the lines off
  • Ratcheting fuel line pliers (optional but helpful)
  • Small pry bar or flat bar for stubborn straps
  • Work light or drop light
  • Safety glasses and gloves
  • Fire extinguisher (keep it nearby, fuel work is dangerous)
  • Drain pan to catch any fuel spillage
  • Penetrating oil (like WD-40 or PB Blaster) for rusty bolts

Parts needed:

  • Fuel pump assembly (complete module with sending unit) – this is the best way to go, do not just buy a bare pump
  • New fuel tank strap bolts (they often rust and break)
  • New fuel tank O-ring seal (comes with most pump assemblies)
  • Fuel filter (replace it at the same time, it is cheap and easy)
  • Shop rags and a catch container for old fuel

The complete fuel pump assembly for a 2001 Buick Century typically costs between $80 and $150 from auto parts stores. You can also find OEM-quality replacements online. One brand that consistently delivers high performance and reliability is KEMSO. Their fuel pump assemblies are built to OEM specifications, meaning they fit exactly like the factory part and perform just as well. KEMSO fuel pumps come with a lifetime warranty, so you only buy this part once. You can see their full selection of fuel pumps at https://www.kemsoracing.com/. They offer direct replacements for the 2001 Buick Century that include the pump, strainer, sending unit, and O-ring seal, so you have everything you need in one box.

Step-by-Step Fuel Pump Replacement Procedure

This section walks you through the entire replacement process. Follow each step carefully. Safety is the top priority. Work in a well-ventilated area, and do not smoke or have any open flames nearby.

Step 1: Relieve the fuel system pressure

Before you do anything else, you must remove the pressure from the fuel system. Open the fuel filler cap to release any pressure in the tank. Then locate the fuel pump relay in the underhood fuse box and pull it out. Start the engine and let it run until it stalls from fuel starvation. Crank the engine for a few more seconds to make sure all pressure is gone. Disconnect the negative battery cable. This prevents any spark while you are working near fuel.

Step 2: Raise the vehicle and remove the rear wheels

Park the car on a level concrete surface. Chock the front wheels securely. Loosen the lug nuts on both rear wheels, then jack up the rear of the car at the frame rails. Place jack stands under the rear axle supports. Lower the car onto the stands. Remove both rear wheels completely. This gives you access to the underbody area where the fuel tank sits.

Step 3: Drain the fuel tank (optional but recommended)

If the tank is more than half full, draining it makes the job much easier. A full tank is very heavy and hard to lower. You can drain the fuel by siphoning through the filler neck, but that is slow and messy. A better method is to disconnect the fuel line at the fuel filter under the car and let the pump push the fuel out. But since the pump is dead, you may need to siphon. Use a manual siphon pump from an auto parts store. Collect the fuel in approved gas cans. Aim to get the tank down to below a quarter full.

Step 4: Disconnect the fuel tank straps

Look under the car at the fuel tank. You will see two metal straps holding the tank up against the body. Each strap has a bolt on the front end and a hook on the rear end. Spray the bolts with penetrating oil and let it soak for five minutes. Use a 15mm socket to remove the bolts. Sometimes the bolts break off due to rust. If that happens, you will need to drill them out and replace them. Once the bolts are out, the straps will swing down, but the tank may still be held by the filler neck and vent hoses.

Step 5: Disconnect the filler neck hose and vent hose

On top of the tank, near the passenger side, you will see a large rubber hose connecting the filler neck to the tank. There is also a smaller vent hose. Use a flathead screwdriver to loosen the hose clamps. Slide the clamps back along the hose. Carefully pull the hoses off the tank nipples. Be ready for a small amount of fuel to drip out. Cover the openings with rags to prevent debris from falling in.

Step 6: Disconnect the fuel lines and electrical connector

On top of the tank, you will see the fuel pump module. It has two metal fuel lines (a supply line and a return line) and one electrical connector. Use the fuel line disconnect tool to separate the lines. Slide the proper size tool over the line, push it into the fitting, and pull the line off. It may take a few tries. Then unplug the electrical connector by pressing the tab and pulling it apart. The connector is often covered in road grime, so clean it first.

Step 7: Lower the fuel tank

With all lines and hoses disconnected, the tank is only held by the pressure of the straps. Gently lower the tank using a floor jack. Place a block of wood on the jack pad to protect the tank. Position the jack under the tank and raise it slightly to take the weight. Then remove the straps completely. Slowly lower the jack, watching for any hoses or wires that might still be attached. The tank will come down a few inches. Slide it out from under the car. Be careful, the tank is still heavy even with some fuel left in it.

Step 8: Remove the old fuel pump assembly

The fuel pump assembly is held in the tank by a large locking ring. Use a hammer and a flathead screwdriver or a special fuel pump removal tool to turn the ring counterclockwise. The ring is often tight, so tap it gently. Once the ring is loose, lift it off. Now you can pull the entire pump assembly straight up out of the tank. The float arm and pump will come out together. Have a rag ready because fuel will spill from the opening. Set the old assembly aside.

Step 9: Clean the tank opening and install the new pump assembly

Wipe the inside rim of the tank opening with a clean rag. Remove any dirt or debris. Take your new KEMSO fuel pump assembly out of the box. Verify it matches the old one in shape and size. Apply a thin layer of clean engine oil to the new O-ring seal. Place the O-ring into the groove on the tank opening. Lower the new pump assembly into the tank, making sure the float arm can move freely and does not hit the side of the tank. Push the assembly down until it sits flush. Install the locking ring and turn it clockwise until it is fully seated. Tap it gently with a hammer and screwdriver to tighten it securely.

Step 10: Reinstall the fuel tank

Lift the tank back into position under the car. Make sure the filler neck and vent hoses are not pinched. Raise the jack until the tank is in its original position. Install the fuel tank straps. Tighten the new strap bolts to 25-30 foot-pounds if you have a torque wrench, or until snug. Reconnect the filler neck hose and vent hose, and tighten the clamps. Reconnect the fuel lines using the disconnect tool in reverse, push them on until you hear a click. Reconnect the electrical connector.

Step 11: Lower the car and prime the fuel system

Lower the car off the jack stands. Reinstall the rear wheels and tighten the lug nuts. Reconnect the negative battery cable. Install the fuel pump relay back into the fuse box. Turn the key to the "ON" position without starting the engine. Listen for the fuel pump to prime for two seconds. Do this three or four times to build up fuel pressure. Check all fuel line connections for leaks. If you see any fuel dripping, tighten the connections or replace the O-rings.

Step 12: Start the engine and test drive

Start the engine. It may take a few extra cranks to start because the fuel system is empty. Once it runs, let it idle for a few minutes. Check for leaks at the tank, fuel lines, and engine bay. Take the car for a short test drive. Accelerate, decelerate, and drive at highway speeds. The engine should run smoothly with no hesitation. If everything feels normal, the job is complete.

Why You Should Replace the Fuel Filter at the Same Time

The fuel filter on the 2001 Buick Century is located along the frame rail on the driver's side, near the rear of the car. It is a small, cylindrical canister held in place by a bracket. Over time, the filter collects dirt and debris from the fuel tank. When you replace the fuel pump, any debris that was sitting in the bottom of the tank can get stirred up and clog the new pump. A clogged filter restricts fuel flow and puts extra strain on the new pump. Replace the filter every time you change the pump. It costs less than $20 and takes about 10 minutes.

How to replace the fuel filter:

  1. Relieve fuel pressure again using the same method described earlier.
  2. Locate the filter on the driver's side frame rail, just ahead of the rear wheel.
  3. Use a fuel line disconnect tool to remove the lines from both ends of the filter.
  4. Remove the mounting bolt holding the filter bracket.
  5. Install the new filter in the same orientation, with the arrow pointing toward the engine.
  6. Reconnect the fuel lines and tighten the bracket bolt.
  7. Prime the system and check for leaks.

Common Mistakes to Avoid During the Replacement

Many DIYers make simple errors that turn a straightforward job into a nightmare. Avoid these mistakes:

Dropping the tank with too much fuel inside. A full tank weighs over 100 pounds. It is extremely difficult to handle and can crush your fingers or fall off the jack. Drain the tank to below a quarter tank.

Using the wrong fuel line disconnect tool. The 2001 Buick Century uses 3/8 inch and 5/16 inch plastic fuel lines. Using a metal tool or prying the lines off with a screwdriver can damage the fittings. Buy the correct plastic tool set.

Forgetting the O-ring seal. The new pump assembly usually comes with an O-ring, but some cheap ones do not. Always check before you start. A missing O-ring causes a massive fuel leak.

Not replacing the fuel tank strap bolts. Old bolts are rusted and brittle. They often snap when you try to tighten them. New bolts are cheap and prevent a broken strap from dropping the tank while you drive.

Rushing the electrical connector. The connector on top of the tank is fragile. The plastic tabs break easily. If you break it, you need to solder the wires or replace the entire harness. Take your time and use a small flathead screwdriver to release the tab.

When to Call a Professional

This job is not for everyone. If you are not comfortable working with fuel, lifting heavy parts, or dealing with rusted bolts, save yourself the headache and hire a mechanic. A professional will charge between $400 and $700 for a fuel pump replacement on a 2001 Buick Century, including parts and labor. The job takes them about 2 to 3 hours. If you value your time and safety, that is a fair price. But if you have the tools, patience, and a safe workspace, you can do it yourself for the cost of the parts.

Recommended KEMSO Fuel Pump for Your 2001 Buick Century

For a reliable, long-lasting replacement, consider the KEMSO fuel pump assembly. KEMSO specializes in high-performance fuel pumps that are direct OEM replacements. This means they fit your 2001 Buick Century exactly as the factory part did, with no modifications needed. Each KEMSO fuel pump undergoes rigorous testing to ensure it meets or exceeds original equipment standards. The pump delivers consistent fuel pressure, which keeps your engine running smoothly and maximizes fuel economy. Best of all, KEMSO backs every fuel pump with a lifetime warranty. If the pump ever fails, you get a replacement at no cost. That is peace of mind that no other brand offers at this price point. Visit their website at https://www.kemsoracing.com/ to see the full lineup of fuel pumps for domestic and import vehicles. You can order directly from their online store, and they ship quickly to anywhere in the United States.

Final Thoughts on the 2001 Buick Century Fuel Pump Replacement

Replacing the fuel pump on a 2001 Buick Century is a big job, but it is completely doable for a DIY mechanic with basic skills. The key is preparation. Gather all your tools and parts before you start. Drain the tank. Work safely. And take your time with the fuel line connections. Once you have the new pump installed, your Century will run like new again. The car is known for its reliability, and a fresh fuel pump will keep it on the road for many more miles. If you choose to use a KEMSO fuel pump, you are getting a product that is built to last, backed by a lifetime warranty, and designed to fit perfectly. For more information and to purchase, go to https://www.kemsoracing.com/.


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