how to diagnose engine misfire in my BMW 5 Series F10/F11 (2010-2017) with code P0301?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety during the repair process.
• Allow the engine to cool down.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil from cylinder 1.
• Use the spark plug socket to remove the spark plug.
• Inspect the spark plug for wear, carbon buildup, or damage.
• If damaged, install a new spark plug with the correct specifications (torque to manufacturer’s specifications, typically around 20 Nm).
• Reinstall the ignition coil.

3. Inspect and Replace Ignition Coil

• Tools Required: Torque wrench, socket set.
• If the ignition coil was found to be faulty during inspection, remove the coil by unscrewing any mounting bolts.
• Disconnect the electrical connector from the ignition coil.
• Install the new ignition coil and reconnect the electrical connector.
• Torque the mounting bolts to manufacturer specifications (usually around 10 Nm).

4. Perform Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 1.
• Insert the compression tester into the spark plug hole.
• Crank the engine a few times to get a reading.
• Compare the compression value to manufacturer specifications (typically between 150-200 psi).
• If the compression is low, further investigation into the engine internals may be necessary.

5. Inspect Fuel Injector

• Tools Required: Fuel injector cleaner or replacement injector.
• If the injector is suspected to be clogged, remove the fuel injector from cylinder 1.
• Clean the injector with a specialized fuel injector cleaner or replace it if it is malfunctioning.
• Reinstall the injector ensuring a proper seal.