Signs of Fuel Pump Failure in a Mercedes-Benz E-Class W213 (2016-2024)

A failing fuel pump can lead to various performance issues in your Mercedes-Benz E-Class W213. Here are the common symptoms indicating a potential fuel pump failure:

Symptoms

1. Engine Stalling: The engine may stall unexpectedly, especially during acceleration or at idle.
2. Difficulty Starting the Engine: The vehicle may take longer than usual to start, or it may not start at all.
3. Loss of Power: You may experience a noticeable drop in power while driving, particularly during acceleration.
4. Poor Fuel Economy: A failing fuel pump can lead to reduced fuel efficiency, as the engine may not be getting the right amount of fuel.
5. Noisy Fuel Pump: A whining or humming noise coming from the fuel tank can indicate a failing pump.
6. Check Engine Light: The check engine light may illuminate due to fuel delivery issues, which could be related to the fuel pump.
7. Vibrations or Pulsations: You may feel vibrations or pulsations in the vehicle while driving, indicating inconsistent fuel delivery.

Diagnostic Steps

1. Visual Inspection:

   • Check for any visible damage or leaks around the fuel tank and fuel lines.
   • Inspect the fuel pump fuse in the fuse box and replace if blown.

2. Fuel Pressure Test:

   • Use a fuel pressure gauge to measure the fuel pressure at the fuel rail.
   • For the W213, the fuel pressure should typically be around 50-60 psi. If it's below specifications, this indicates a possible fuel pump issue.

3. Listen for Pump Operation:

   • Turn the ignition key to the "ON" position (do not start the engine) and listen for a humming noise from the fuel tank for a few seconds. If you do not hear anything, the pump may be faulty.

4. Scan for Error Codes:

   • Use an OBD-II scanner to check for any diagnostic trouble codes (DTCs) related to fuel delivery or the fuel system.

5. Check Fuel Filter:

   • A clogged fuel filter can mimic fuel pump failure symptoms. Inspect and replace the fuel filter if needed.

Tools Required

• OBD-II Scanner
• Fuel Pressure Gauge
• Multimeter (for electrical testing)
• Basic Hand Tools (screwdrivers, wrenches, etc.)
• Safety Glasses
• Fuel Line Disconnect Tool
• Jack and Jack Stands (if needed for access)

Repair Instructions

Step 1: Access the Fuel Pump

1. Safety First: Ensure the vehicle is parked on a flat surface, and disconnect the negative battery terminal to prevent electrical issues.
2. Raise the Vehicle: If necessary, use a jack and jack stands to elevate the rear of the vehicle for better access.
3. Remove Rear Seat: In many cases, the fuel pump access is under the rear seat. Remove the seat bottom and locate the access cover.

Step 2: Test the Fuel Pump

1. Check Electrical Connections: Ensure all wiring and connectors to the fuel pump are secure and free of corrosion. Use a multimeter to test for voltage at the pump connector.
2. Remove the Fuel Pump: Disconnect the fuel lines using a fuel line disconnect tool and remove the electrical connector. Unscrew the retaining ring and lift the pump assembly out of the tank.
3. Check Pump Operation: If you have a replacement pump, test it outside of the tank by applying power to it and ensuring it operates.

Step 3: Replace the Fuel Pump (if necessary)

1. Install New Pump: If the pump is faulty, install the new fuel pump into the assembly, ensuring all seals are correctly placed.
2. Reconnect Fuel Lines: Carefully reconnect the fuel lines and electrical connector, ensuring they are secure.
3. Reinstall Access Cover: If you removed an access cover, reinstall it back onto the vehicle.

Step 4: Test the New Installation

1. Reconnect Battery: Reconnect the negative battery terminal.
2. Turn Key to ON: Cycle the ignition to the "ON" position and listen for the pump operation.
3. Start the Engine: Start the engine and check for leaks or any abnormal noises.
4. Perform Fuel Pressure Test: Check the fuel pressure again to ensure it is within specifications.

Step 5: Final Checks

• Clear any DTCs if present and take the vehicle for a test drive to confirm proper operation.

By following these steps, you can effectively diagnose and repair fuel pump issues in a Mercedes-Benz E-Class W213. Always consult the vehicle's service manual for specific details and torque specifications.