how to fix P0302 misfire in BMW 3 Series F30/F31 (2012-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to avoid any electrical issues during repairs.
• Allow the engine to cool down before beginning work.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench.
• Remove the ignition coil for cylinder 2 by unscrewing the retaining bolts.
• Carefully pull out the ignition coil.
• Use the spark plug socket to remove the spark plug from cylinder 2.
• Inspect the spark plug for wear (electrode condition, carbon buildup).
• Replace with a new spark plug, ensuring it is gapped correctly (typically 0.028 inches for BMW).
• Torque the spark plug to manufacturer specifications (usually around 18 lb-ft).

3. Test and Replace Ignition Coil

• Tools Required: Multimeter.
• Reconnect the ignition coil and check for voltage using a multimeter while cranking the engine.
• If there is no voltage or the coil is not functioning, replace the ignition coil with a new one.
• Reinstall the ignition coil and securely fasten it.

4. Inspect and Clean Fuel Injector

• Tools Required: Fuel injector cleaning kit or professional cleaning service.
• Disconnect the fuel line and electrical connectors from the fuel injector for cylinder 2.
• Remove the injector using appropriate tools.
• Clean the injector or replace it if it is clogged or malfunctioning.
• Reinstall the injector, ensuring it is seated properly.

5. Check Compression

• Tools Required: Compression tester.
• Remove the spark plug for cylinder 2.
• Insert the compression tester and crank the engine several times.
• Compare the compression reading with manufacturer specifications (usually around 150-200 psi).
• If the compression is low, further engine diagnostics may be required.