my BMW 3 Series F30/F31 (2012-2019) has a hard time starting what could be the issue

Solution

1. Preparation

• Gather tools and safety gear.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative terminal of the battery to prevent electrical shock.

2. Battery Inspection

• Tools Required: Multimeter, wire brush, wrench set
• Clean any corrosion from the battery terminals using a wire brush.
• Check battery connections to ensure they are tight and secure.
• If the battery voltage is below 12.4 volts, consider charging or replacing the battery.

3. Starter Motor Testing

• Tools Required: Jumper cables, multimeter
• Connect the positive lead of the multimeter to the starter motor’s positive terminal.
• Use jumper cables to connect the starter directly to the battery.
• If the starter engages and the engine starts, replace the starter motor.

4. Fuel System Check

• Tools Required: Fuel pressure gauge, basic hand tools
• Locate the fuel rail and connect the fuel pressure gauge.
• Turn the ignition key to the "On" position (without starting the engine) to check for fuel pressure.
• If pressure is below the manufacturer's specification, replace the fuel pump.

5. Ignition System Inspection

• Tools Required: Spark plug socket, torque wrench
• Remove and inspect the spark plugs for wear or fouling.
• Replace any faulty spark plugs and ensure they are torqued to the manufacturer's specifications (typically around 15 ft-lbs).
• Inspect ignition coil connectors for corrosion or damage and replace as necessary.