how to diagnose engine misfires in my BMW 5 Series G30/G31 (2017-2024)?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool before starting any work.

2. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the ignition coil connectors.
  3. Use a spark plug socket to carefully remove each spark plug.
  4. Inspect for wear, carbon buildup, or damage, and replace if needed.
  5. Install new spark plugs, ensuring the correct gap, and torque to the manufacturer’s specifications (typically around 20 Nm).

3. Test and Replace Ignition Coils

• Sub-steps:
  1. Remove the ignition coils from the engine by unbolting them.
  2. Test each coil with a multimeter to ensure they are within specified resistance values.
  3. Replace any faulty coils with new ones, ensuring proper seating and connection.

4. Check and Replace Fuel Injectors

• Sub-steps:
  1. Relieve fuel system pressure by removing the fuel pump fuse and starting the engine until it stalls.
  2. Disconnect the fuel lines and electrical connectors from the fuel injectors.
  3. Remove the injectors and inspect for clogs or damage.
  4. Clean or replace the injectors as necessary, ensuring proper sealing upon installation.

5. Inspect Air Intake and Vacuum System

• Sub-steps:
  1. Visually inspect all hoses and connections for cracks or leaks.
  2. Use a smoke machine to identify any hidden vacuum leaks.
  3. Replace any damaged hoses or components to ensure a tight seal.