Home1998-2006 3 Series (E46)BMW E46 Fuel Pump Replacement - 1998-2006 3 Series - All Models

BMW E46 Fuel Pump Replacement – 1998-2006 3 Series – All Models

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Repair Summary
The following article gives detailed instructions on replacing the fuel pump in a BMW E46 3 series vehicle. Even though we have used a 2003 325ci to perform this repair, this article can be applied to any 1998-2006 E46 vehicle with minor modifications.

A BMW E46 fuel pump replacement is a basic repair that can be performed in less than an hour.

One of the most common issues afflicting older BMW E46 3 series cars is a failing or broken fuel pump. Like all mechanical parts on your BMW, the fuel pump has a limited lifespan...it, unfortunately, doesn't last forever. Age and general wear and tear take their toll on internal parts, causing the pump to lose its ability to create and hold proper fuel pressure. Dirt and debris in the fuel can slowly clog the pump causing it to overheat under the additional workload leading to pump failure. A BMW E46 fuel pump can deteriorate slowly or it can break down without warning...there is unfortunately no standard formula. Common symptoms of a failing pump include engine hard to start, engine stalling, whining or irregular sound coming from under the rear seat, and decreased performance. If the fuel pump completely fails, the vehicle will not start.
The BMW E46's fuel pump is located underneath the rear seat on the right side of the vehicle. It is an "in-tank" submersible pump that draws fuel through an inlet valve and pressurizes it through a feed line to the engine's fuel injectors. The E46's fuel pump is controlled by the vehicle's DME (engine control unit). When the ignition key is turned to the start position, the DME closes the fuel pump relay allowing power to be sent to the pump. The fuel pump operates continuously while the engine is running providing a steady flow of pressurized fuel to the engine.
The good news is a BMW E46 fuel pump replacement is a relatively simple repair, even for the beginner mechanic. The pump is easily accessed under the rear seat and there are no special tools needed to complete the repair. In fact, a BMW E46 fuel pump replacement can be performed in about 30 minutes with just a socket wrench and flat blade screwdriver.
Since there are other factors that can cause a BMW E46 fuel pump not to operate, we strongly recommend reading our article BMW E46 Fuel Pump Test . Even though the article deals specifically with E46 325i models, it gives excellent information on diagnosing relay-controlled fuel pumps in any BMW.
View the detailed parts diagram for this repair.
Includes detailed part diagrams, part numbers and links to purchase all of the required components needed to complete this repair.
Before starting this repair, you must have the following required parts.
All BMW E46 models
A failing fuel pump has many potential symptoms, including: hard starting cold or after a heat soak, an illuminated check engine light, engine misfire under load or when cold, stalling, or a no-start.
All BMW E46 models
Gasket between the fuel pump/sending unit assembly and retaining collar that secures the assembly to the fuel tank.
All BMW E46 models
A standard high-quality E46 fuel pump for our European friends. (45% off year-round with code 'GSF45REW')
Repair Steps
Section 1 - BMW E46 Fuel Pump Replacement
As mentioned earlier in this article, replacing the fuel pump in your BMW E46 is a simple procedure that can usually be done in less than 30 minutes. Always install the rubber sealing gasket in the top of the gas tank before installing the pump (see step 10 below). You will not get the locking ring back on the pump if you do not install the gasket first.
  1. The BMW E46 fuel pump is located under the rear seat of the vehicle. To access it, grasp the bottom of the rear seat and pull out and up to release it from the body of the car. Use a bungee cord if necessary to safely stow it out of the work area.bmw E46 fuel pump replacement - Grasp right side of rear seat and pull out and up bmw E46 fuel pump replacement - Grasp the left side of the rear seat and pull out and up bmw E46 fuel pump replacement - Use a bungee cord to hold the rear seat out of the work area
  2. Lift the sound insulation off of the top of the fuel pump and fold it backwards. You can now access the fuel pump cover. bmw E46 fuel pump replacement - Lift the sound insulation off of the top of the fuel pump and fold it back.
  3. Use a 10mm socket wrench to remove the four nuts securing the fuel pump cover. Remove the fuel pump cover and lay to the side out of the work area.bmw E46 fuel pump replacement - Use a 10mm socket wrench to remove the four cover mounting nuts bmw E46 fuel pump replacement - Remove the fuel pump cover and lay out of the way
  4. Grasp the fuel pump electrical connection and slide its locking mechanism out to release it. Disconnect the plug from the pump.bmw E46 fuel pump replacement - Slide the plastic lock open on the fuel pump plug Pull the plug out of the fuel pump
  5. Use a flat blade screwdriver to loosen the hose clamp securing the fuel feed line to the pump's outlet tube. Grasp the fuel feed line and pull it free from the outlet tube.bmw e46 fuel pump replacement - Loosen the hose clamp attaching the fuel feed line to the pump. Pull the fuel feed line free from the pump
  6. Use a flat blade screwdriver to loosen the fuel pump's locking ring. Position the flat blade screwdriver behind one of the locking ring's raised tabs and use the palm of your hand to gently loosen it in a counterclockwise direction.bmw e46 fuel pump replacement - use a flat blade screwdriver to loosen the locking ring
  7. Remove the locking ring from the pump.bmw e46 fuel pump replacement - Remove the locking ring from the pump.
  8. Grasp the fuel pump and remove it from the fuel tank.Remove the fuel pump from the gas tank
  9. If your new pump didn't come with a rubber sealing gasket (and you didn't purchase a new one from our parts list), then remove the gasket from the old pump.
  10. Install the rubber sealing gasket in the fuel pump opening in the top of the gas tank. It is very important that the gasket is installed before the pump. You will not be able to get the locking ring back on if you don't install the gasket first.bmw e46 fuel pump replacement - Install the sealing gasket in the gas tank opening bmw e46 fuel pump replacement - A properly installed sealing gasket
  11. Carefully install the new pump into the gas tank, being careful not to pull or twist the rubber gasket. Note that the tab on the back of the pump must line up with the opening on the top of the tank (see image below).bmw e46 fuel pump replacement - Install the new fuel pump into the gas tank
  12. Press the pump down with the palm of your hand to seal it into the rubber gasket.bmw e46 fuel pump replacement - Use the palm of your hand to push the pump down until it is seated in the rubber gasket
  13. Reinstall the locking ring. Use a flat blade screwdriver and the palm of your hand to tighten the ring in a clockwise direction until it is snug. DO NOT over tighten the ring.Reinstall the locking ring and use a flat blade screwdriver to tighten it
  14. Reattach the pump's electrical connection.
  15. Reinstall the back seat cushion.
  16. Test the car for proper operation.
BMW E46 Fuel Pump Replacement Finished
Genuine BMW E46 M3 Fuel Baffle Support
Part #: 16112229656
Genuine BMW E46 Fuel Pump Control Unit
Part #: 16146912019
Bremmen Parts E46 M3 Fuel Pump
Part #: 16142229684
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