How to Deal with Unstable Idle Speed in BMW 1 Series When the Engine is Cold?
2 Answers
Check whether there is excessive carbon buildup in the intake system, such as the throttle valve and idle speed valve; inspect whether the fuel pressure is too low and whether the fuel injector's atomization is poor; examine whether the ignition system's performance is subpar. The engine's power comes from the combustion of fuel, which is achieved through the combined efforts of the fuel injection system, ignition system, and mechanical structure. Therefore, unstable idle speed is often caused by abnormalities in these systems. Below is an introduction to BMW: 1. BMW (Bavarian Motor Works), fully known in Chinese as Bayerische Motoren Werke AG, is a German luxury car brand. BMW's vehicle series include the i, X, Z, and pure numerical models, as well as the 1, 2, 3, 4, 5, 6, 7, and 8 series. 2. BMW was founded in 1916 and is headquartered in Munich, Bavaria, Germany. The blue and white logo of BMW represents the colors of the Bavarian state flag, where the company's headquarters is located.
I also experienced unstable idling issues with my BMW 1 Series, especially during cold starts. The car would shake violently, feeling like it was dancing, and fuel consumption noticeably increased. This is mostly caused by excessive carbon buildup in the throttle body, which affects precise air flow control, or a dirty mass air flow sensor that can't read data correctly. I recommend cleaning the throttle body first—it's inexpensive and can be done DIY or at a shop. After cleaning, reset the ECU to let the computer relearn idle settings, which might solve the problem. If not, check for worn spark plugs or loose ignition coils, as older BMWs often have ignition system issues. Long-term carbon buildup can also clog fuel injectors, so regular maintenance like using fuel additives to clean deposits is crucial. Don't delay fixing this—address it early to avoid engine damage.
