why does my BMW X5 G05 (2019-2024) have a rough cold start

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety during repairs.
• Allow the engine to cool if it was recently operated.

2. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the ignition coil cover (if applicable) using a socket set.
  2. Disconnect the ignition coils from the spark plugs.
  3. Remove the old spark plugs using a spark plug socket and ratchet.
  4. Inspect the spark plug gaps and condition; replace with OEM-spec plugs if necessary.
  5. Install the new spark plugs by threading them in by hand and then tightening to the manufacturer’s torque specification.
  6. Reconnect the ignition coils and replace the ignition coil cover.

3. Check and Replace Fuel Filter (if necessary)

• Sub-steps:
  1. Locate the fuel filter (may be integrated into the fuel pump assembly).
  2. Relieve fuel system pressure by removing the fuel pump fuse and running the engine until it stalls.
  3. Disconnect fuel lines carefully, using appropriate safety equipment.
  4. Remove the old fuel filter and install the new one, ensuring correct orientation.
  5. Reconnect the fuel lines and replace the fuel pump fuse.
  6. Turn the ignition to the "ON" position (without starting) to prime the fuel system.

4. Test Coolant Temperature Sensor

• Sub-steps:
  1. Locate the coolant temperature sensor, typically near the thermostat housing.
  2. Disconnect the electrical connector from the sensor.
  3. Use a multimeter to check the sensor’s resistance at various temperatures.
  4. If out of specification, replace the coolant temperature sensor.
  5. Reconnect the electrical connector after replacement.