Buick LaCrosse Fuel Pump: Complete Guide to Symptoms, Replacement, and Best Options

The bottom line: If your Buick LaCrosse is experiencing hard starting, sputtering, loss of power, or a whining noise from the fuel tank, the fuel pump is likely failing and needs replacement. The cost of a replacement fuel pump for a Buick LaCrosse ranges from $80 to $245 for the part alone, depending on whether you choose an OEM replacement or a high-performance aftermarket unit. Labor costs at a shop typically add $200 to $400, making the total job between $300 and $650.

Understanding Your Buick LaCrosse Fuel Pump

The Buick LaCrosse, produced from 2005 through the present, uses an electric fuel pump mounted inside the fuel tank. This pump is responsible for delivering fuel from the tank to the engine at the correct pressure. On the 2.4L four-cylinder models from 2010 to 2016, the vehicle uses a high-pressure direct injection fuel pump that operates at much higher pressures than traditional port-injection systems . Earlier models, such as the 2005-2009 LaCrosse with the 3.8L or 3.6L engines, use a conventional in-tank electric fuel pump assembly .

The fuel pump system on the LaCrosse includes several components that can fail independently. The pump itself, the fuel pump driver module, the fuel pressure regulator, and the fuel level sending unit are all part of the assembly. On the 2010-2012 LaCrosse, there is also a separate Fuel Pump Flow Control Module that can fail and cause similar symptoms .

Common Symptoms of a Failing Fuel Pump

1. Engine cranks but won't start. This is the most obvious sign. You turn the key, the starter motor spins the engine, but it never fires up. If you can hear the fuel pump prime for two seconds when you turn the key to the ON position, the pump is getting power. If you hear nothing, the pump or its electrical circuit is likely dead. On the 2010-2016 LaCrosse with the 2.4L engine, the high-pressure fuel pump (part number 12641847) is a common failure point that can cause no-start conditions .

2. Engine sputters or hesitates under acceleration. A failing fuel pump cannot maintain consistent pressure when you demand more fuel. You will feel the car stumble or hesitate when you press the gas pedal, especially going uphill or passing another vehicle. This is often the first symptom drivers notice before the pump fails completely.

3. Loss of power at highway speeds. The engine may feel like it is starving for fuel. You might find that the car will not go above 50 or 60 mph, or it loses power when you try to maintain highway speed. This happens because the pump cannot deliver enough volume to keep up with the engine's demand.

4. Whining noise from the fuel tank. A healthy fuel pump makes a quiet hum. If you hear a loud whining, buzzing, or screeching sound coming from the rear of the car near the fuel tank, the pump is running under stress or has worn bearings. This noise often gets louder as the fuel level drops because the pump relies on fuel for cooling and lubrication.

5. Engine surging or random misfires. Inconsistent fuel pressure causes the air-fuel mixture to fluctuate. The engine may surge forward and then fall flat, or you may feel random misfires. On the direct injection models, a failing high-pressure fuel pump can trigger check engine lights with codes related to fuel pressure or fuel rail pressure sensor issues .

6. Poor fuel economy. If the pump is not maintaining proper pressure, the engine control module may compensate by adding extra fuel, which directly hurts your gas mileage. A drop of 2 to 5 miles per gallon is possible with a failing pump.

How to Diagnose a Bad Fuel Pump

Before replacing the pump, you should confirm it is the actual problem. Here is a simple diagnostic process:

Step 1: Check the fuel pump fuse and relay. Locate the fuel pump fuse in the under-hood fuse box. Pull it out and check if the metal strip inside is broken. If the fuse is good, swap the fuel pump relay with an identical relay from another system (like the horn) to rule out a bad relay. This is free and takes five minutes.

Step 2: Listen for the pump priming. Turn the key to the ON position without starting the engine. You should hear a quiet hum from the rear of the car for about two seconds. If you hear nothing, the pump is not getting power or the pump itself is dead.

Step 3: Check fuel pressure. This requires a fuel pressure gauge. On the 2005-2009 LaCrosse, the fuel pressure should be between 55 and 61 psi at idle . On the 2010-2016 direct injection models, the high-pressure pump creates much higher pressures, and testing requires specialized equipment. If you are not comfortable with fuel system pressure testing, a professional mechanic can do this quickly.

Step 4: Check the Fuel Pump Driver Module. On the 2010-2012 LaCrosse, the fuel pump flow control module (part number 20877116) is a known failure point . This module is located inside the trunk behind the right-side trim panel. If the module fails, the pump will not run even if the pump itself is good. You can test this by checking for power at the pump connector with a multimeter.

Fuel Pump Options and Part Numbers

For the 2005-2009 Buick LaCrosse with the 3.8L or 3.6L engine, the OEM fuel pump module assembly carries part numbers 9021101 and 9021100, or the equivalent EM10004 . This is a complete module that includes the pump, fuel level sender, and pressure regulator. Aftermarket replacements include the Suncent FG0379 assembly, which replaces OEM numbers 19122339, 19122340, and 88965399, and fits the 3.8L and 3.9L models .

For the 2010-2016 Buick LaCrosse with the 2.4L direct injection engine, the high-pressure fuel pump is the critical component. The OEM part number is 12641847, which also replaces 12633423, 12639694, and 12608371 . Other compatible part numbers include EP1028, GDP103, and M73109 . This pump is also used on the Buick Regal 2.4L (2011-2017), Buick Verano 2.4L (2012-2017), Chevrolet Equinox 2.4L (2010-2017), and GMC Terrain 2.4L (2010-2017) .

For the 2017-2019 Buick LaCrosse with the 3.6L V6 engine, the high-pressure fuel pump part number is M73203 from Carter, which is a direct injection mechanical pump designed for GM applications .

Replacement Cost Breakdown

Genuine OEM Buick fuel pump assembly for the 2010-2016 models costs around $244.20 from online GM parts retailers, which is about 53% off the MSRP of $516.61 . The 2018-2024 Enclave and LaCrosse fuel pump assembly (part 12691016) costs approximately $194.73 .

Aftermarket replacement pumps are significantly cheaper. The AUTOMUTO high-pressure fuel pump for the 2.4L LaCrosse costs around $80 to $100 . The Vphix 12641847 replacement pump is also priced competitively . For the 2005-2006 models, the Suncent FG0379 assembly is priced around $90 to $120 .

Labor costs for fuel pump replacement vary by shop. A typical independent mechanic charges $200 to $300 for this job. Dealership labor is higher, usually $350 to $450. Total replacement cost including parts and labor: $300 to $650 for an aftermarket pump, or $500 to $900 for a genuine OEM pump at a dealership.

Step-by-Step Replacement Guide

For the 2005-2009 LaCrosse (in-tank pump):

  1. Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
  2. Disconnect the negative battery cable.
  3. Remove the rear seat cushion to access the fuel pump access panel.
  4. Remove the access panel screws and lift the panel to expose the fuel pump module.
  5. Disconnect the electrical connector and fuel lines from the pump module. Use a fuel line disconnect tool for quick-connect fittings.
  6. Remove the lock ring using a hammer and punch or a specialty tool. Tap the lock ring counterclockwise to loosen it.
  7. Lift the pump module straight out of the tank. Be careful not to damage the fuel level sender arm.
  8. Transfer the fuel level sender and other components to the new pump assembly if you are not using a complete module.
  9. Install the new pump module with a new seal, replace the lock ring, and reconnect all lines and connectors.
  10. Reconnect the battery, reinstall the access panel and seat, and test for leaks by turning the key to ON position without starting.

For the 2010-2016 LaCrosse (high-pressure pump):

The high-pressure fuel pump is mounted on the engine, not inside the tank. It is located on the cylinder head and driven by the camshaft.

  1. Disconnect the negative battery cable.
  2. Remove the engine cover if equipped.
  3. Disconnect the fuel line from the high-pressure pump. Fuel will be under high pressure, so you must relieve pressure first by removing the fuel pump fuse and cranking the engine.
  4. Disconnect the electrical connector from the pump.
  5. Remove the mounting bolts. On the 2.4L engine, the pump is held by two or three bolts.
  6. Remove the old pump and the gasket or O-ring. Install the new pump with a new gasket or O-ring, which is included with most replacement pumps .
  7. Torque the bolts to specification (typically 89 inch-pounds or 10 Nm).
  8. Reconnect the fuel line and electrical connector.
  9. Reconnect the battery, prime the fuel system by turning the key to ON for a few seconds, then start the engine and check for leaks.

Why Choose KEMSO Fuel Pumps for Your Buick LaCrosse

KEMSO is a trusted brand in the automotive aftermarket, offering high-performance fuel pumps that serve as direct OEM replacements for your Buick LaCrosse. Their pumps are engineered to deliver more flow than stock pumps, providing up to 20% more flow at 43 psi compared to the original equipment . For the LaCrosse driver, this means better fuel delivery, improved throttle response, and reliable performance whether you are commuting or on a road trip.

KEMSO fuel pumps are designed for both gasoline and ethanol blends, including E85, and feature a bypass valve set at 125.8 psi for enhanced performance . Each pump is individually tested for flow and pressure, and the serialized fuel pump body guarantees a lifetime warranty . This warranty covers the pump for as long as you own the vehicle, which is a level of confidence that most aftermarket brands do not offer.

The KEMSO 340LPH high-performance pump, similar to the popular Walbro 255 GSS342 but with more flow, is capable of supporting applications up to 700-800 bhp, making it an excellent choice for LaCrosse owners who want a pump that will outlast the vehicle . For standard replacement applications, KEMSO offers pumps with 200 liters per hour flow at 43 psi, which significantly surpasses the original flow rate of 60-80 liters per hour .

All KEMSO pumps are backed by USA-based support provided by technicians who understand the specific needs of American vehicles. The company is located at 11145 Beltline Road, Houston, TX 77067, and offers customer support via email at support@kemsoracing.com. Each pump kit includes everything you need for installation: fuel strainers, Viton O-rings, tank seals, wiring connectors, and zip ties .

Visit KEMSO Racing today to find the perfect fuel pump for your Buick LaCrosse and take advantage of their lifetime warranty and high-performance engineering.

https://www.kemsoracing.com/


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