why is my Volkswagen Passat B8 (2015-2022) using so much fuel?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety while working on electrical components.

2. Address Fuel System Issues

1. Check Fuel Pressure

   • Connect the fuel pressure gauge to the fuel rail.
   • Start the engine and observe pressure readings.
   • Compare readings with manufacturer specifications; replace the fuel pump if pressure is low.

2. Inspect and Clean Fuel Injectors

   • Remove the fuel rail from the engine, taking care to avoid fuel spillage.
   • Disconnect the electrical connectors from the fuel injectors.
   • Use a fuel injector cleaning kit to clean the injectors or replace them if they are clogged.

3. Inspect Air Intake System

1. Check for Leaks

   • Visually inspect all air intake hoses and connections for cracks or loose fittings.
   • Use smoke testing if necessary to detect vacuum leaks.
   • Replace any damaged hoses or gaskets.

2. Clean Mass Air Flow Sensor

   • Carefully remove the MAF sensor from the air intake path.
   • Use MAF sensor cleaner to clean the sensor element; allow it to dry before reinstallation.

4. Examine and Replace O2 Sensors

• Locate the upstream and downstream O2 sensors.
• Disconnect the electrical connectors and remove the sensors using an O2 sensor socket.
• Install new sensors according to manufacturer's torque specifications.

5. Inspect Engine Oil

• Check engine oil level; if excessively low, top off or change the oil.
• Look for signs of oil consumption (e.g., blue smoke from the exhaust), which may indicate further engine issues.