how to troubleshoot my BMW 3 Series G20/G21 (2019-2024) if it stalls after starting?

Solution

1. Preparation

• Gather tools: OBD-II scanner, fuel pressure gauge, socket set, multimeter, and cleaning supplies.
• Disconnect the negative battery terminal to ensure safety.

2. Fuel System Inspection

• Sub-step 1: Connect the fuel pressure gauge to the fuel rail.
• Sub-step 2: Turn the ignition to the "ON" position without starting the engine and check the pressure reading against manufacturer specifications (typically 50-60 psi for BMW).
• Sub-step 3: If the pressure is low, check for fuel pump operation and relay function. Replace the fuel pump if necessary.

3. Air Intake System Cleaning

• Sub-step 1: Remove the air filter and inspect it for dirt or damage; replace if necessary.
• Sub-step 2: Use a throttle body cleaner to clean the throttle body, ensuring no carbon buildup obstructs airflow.
• Sub-step 3: Reinstall the air filter and throttle body after cleaning.

4. Ignition System Check

• Sub-step 1: Remove the spark plugs using a socket set.
• Sub-step 2: Inspect each spark plug for wear, carbon buildup, or damage; replace if necessary.
• Sub-step 3: Check ignition coils for proper function using a multimeter; replace any faulty coils.

5. Battery and Electrical System Check

• Sub-step 1: Test the battery voltage with a multimeter; it should read above 12.4 volts.
• Sub-step 2: Inspect battery terminals for corrosion and ensure they are tightly connected.
• Sub-step 3: If battery voltage is low, recharge or replace the battery.