Starting a BMW in cold weather can sometimes be challenging, but it’s important to identify and resolve the issue promptly. There are various reasons why a BMW might not start in cold weather, including dead batteries, clogged fuel injectors, and cold-related engine problems. To resolve the issue and get your BMW running smoothly again, it’s important to identify the cause of the problem, potentially with a YOUCANIC full system OBD-II scanner, and take the appropriate steps to fix it. In this article, we’ll explore some of the most common causes of BMWs not starting in cold weather and what you can do to solve the issue.
The BMW may not start in cold weather and can affect all BMW vehicles, including 1, 3, 5, 7, X1, X3, and X5 series. Typical symptoms include the engine turning over slowly and then stopping. You may be able to start the BMW by either cranking the engine several times or waiting until it gets warmer, which is not the ideal solution. This list of items can prevent a BMW from starting in cold weather.
The first thing that needs to be checked is the battery. This problem can be due to a battery near the end of its life. Battery performance decreases as the temperature decreases. Therefore, it may be harder to start the car if it is cold outside.
The BMW may not start in cold weather for several other reasons. Especially if the engine is turning over without a problem, the battery is charged but refuses to start. The BMW battery may be new, but it must still be registered.
Faulty Spark Plugs or Coils
Old or worn-out spark plugs can cause a BMW to struggle to start in cold weather, as they are responsible for igniting the fuel and air mixture in the engine. If the spark plugs haven’t been replaced in a while, they may not produce a strong enough spark to ignite the fuel and air mixture, causing the engine to crank but not start. Additionally, worn-out spark plugs can cause misfires, leading to a decrease in engine performance and efficiency. Replacing the spark plugs with new ones can quickly solve the problem and prevent further damage to the engine, allowing your BMW to start easily, even in cold weather. It is recommended to replace spark plugs every 100,000 miles or as the manufacturer recommends.
The BMW may not start with low fuel pressure, a bad fuel pump relay, or a faulty fuel pump. A bad fuel pump can also cause this problem. If you have a fuel pressure gauge, you can quickly check the fuel pressure in the morning. Another test you can perform is to cycle the ignition three or four times without cranking the engine. This should build up the required pressure to start the car.
The fuel pump relay may stick when the outside temperature drops drastically. To verify this, remove the fuel pump relay. Take it inside and warm it to room temperature. Do not use methods that would melt the relay. Reinstall it while it is still cold outside, and start the engine. If the engine starts, replace the relay when the relay is warmed.
The variable intake valve control system may be why your BMW won’t start. VANOS adjusts the valves during engine warm-up for the best fuel/air ratio. VANOS is designed to adjust valves at high RPM but can also impact cold-weather performance.
Engine temperature sensor / PCM Coolant Sensor
The engine coolant temperature sensor may also malfunction, making it harder for your BMW to start in the morning. Read the fault codes from the Engine Control Unit (DME). If you have fault codes related to the engine temperature sensor, replace them.
In conclusion, when a BMW won’t start in cold weather, it’s important to identify the cause and take the appropriate steps to resolve the issue. Whether it’s a dead battery, clogged fuel injectors, or another cold-related problem, fixing it will ensure your BMW runs smoothly and gets you where you need to go. The YOUCANIC Full System Scanner can help you read and clear fault codes from all the systems in your BMW.
Regular maintenance and preventative measures, such as ensuring your battery is in good condition, using the right fuel, and keeping your fuel injectors clean, can help prevent BMW cold weather starting problems. If you’re still having trouble, consult a BMW specialist or mechanic to diagnose and repair any underlying issues. Don’t let cold weather keep you from driving your BMW. Take the necessary steps to ensure it starts every time, no matter the temperature.
We hope you find the BMW Won’t Start in Cold Weather guide helpful. Check these troubleshooting and repair guides for more help on your BMW.
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