why does my BMW 3 Series F30/F31 (2012-2019) engine knock on acceleration

Solution

1. Preparation

• Gather all necessary tools and safety equipment.
• Disconnect the negative battery terminal to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plugs

• Tools Required: Spark plug socket, torque wrench, gap gauge
• Remove the ignition coils using a socket wrench.
• Extract the spark plugs using a spark plug socket.
• Inspect the spark plugs for wear, carbon buildup, or damage.
• Replace with new spark plugs if necessary, ensuring they are gapped correctly per manufacturer specifications (typically between 0.028-0.032 inches).
• Reinstall the ignition coils securely.

3. Check and Replace Fuel Quality

• Tools Required: Fuel pressure gauge, siphon pump (if required)
• Check the fuel pressure to ensure it meets specifications (consult service manual for specific values).
• If low pressure is detected, consider replacing the fuel filter.
• If using low-octane fuel, drain the tank and refill with high-octane fuel as recommended by BMW.

4. Clean Combustion Chamber

• Tools Required: Engine cleaner, brush set, vacuum
• Use a carbon cleaning solution and follow the manufacturer's instructions for application.
• Scrub the combustion chamber gently with a brush to remove carbon deposits.
• Vacuum any debris from the engine bay after cleaning.

5. Verify Engine Timing

• Tools Required: Timing light
• Connect the timing light to the battery and the number one spark plug wire.
• Start the engine and check the timing mark against the manufacturer's specifications.
• Adjust the timing if necessary by loosening the distributor hold-down and rotating it gently.