Reasons Behind Engine Misfires in BMWs

BMWs represent some of the highest quality in German engineering and innovation. Made to last and with quality in mind, it is unlikely you’ll experience issues with your car for sometime after purchase. However, even the best-made cars will show signs of wear and tear as they age, and in this article, we will be taking a closer look at engine misfires, what they are, what causes them, and what you should do about them.

What does it mean when an engine misfires?

We’ve all heard of the term “engine misfire,” but what actually happens under the hood when this happens? An engine misfire occurs when the engine of your vehicle skips or does not successfully complete one of the steps in the combustion process.

Most engines have a 4-step or 4-stroke combustion process. Step 1 is intake, which is where the piston, cylinder, and crankshaft of your car work together to let a mixture of fuel and air into your engine via the inlet valve.

Step 2 is compression, which begins with the closing of the inlet valve. The piston then retracts into the cylinder which tightly compresses the concoction of fuel and air, increasing its flammability. Once maximum pressure is reached, the spark plug fires.

Step 3 is power, otherwise known as combustion. The spark created by the spark plug causes a small explosion when it ignites, releasing a hot gas that causes the piston to drop. The energy that has been released now starts to power the crankshaft.

The final step is the exhaust. The outlet valve opens, and exhaust gases that have been created by the burning fuel are forced by the piston out of the exhaust pipe.

If any of these processes run incorrectly or fail to run, engine misfire will occur. Because of the different processes involved in the combustion of your car’s engine, misfire can be defined in multiple ways: lean misfire (to do with air/fuel ratio), ignition misfire (to do with any part involving in the ignition process, i.e., spark plugs), and mechanical misfires (to do with the failure of any of the car’s mechanical parts, i.e., pistons and valves).

Faulty Wiring

Misfires caused by faulty wiring can be quite common in BMWs as they age. The daily-use wiring that is required when your car is running are usually the first to show signs of deterioration. In regards to an engine, the most common fault can come from failed or faulty spark plug wiring. Without the spark plugs working effectively, your BMW will not be able to properly ignite the air/fuel mixture, meaning your car may not start or will run very poorly. Therefore, keeping your BMW’s spark plugs well maintained is essential.

Damage to Crank Position Sensor

As we’ve discussed, the crankshaft is essential to the running of your car’s engine. Because of this, it has a crank position sensor, which allows your BMW’s onboard computer to regulate the position of the shaft and the timing of the engine. This helps to ensure all the various parts and components are running smoothly. If this part is damaged, it is unlikely your car will start properly, if at all.

Head Gasket Damage

The head gasket is essential to achieve maximum fuel compression, which leads to the successful ignition of the fuel. If the head gasket becomes damaged, it can constitute a serious issue for your vehicle and should be dealt with immediately. If it is overlooked, it could seriously damaged your car by creating incorrect pressure, putting strain on other parts, or even causing a rupture or critical damage to them.

Euro Plus Automotive

Any issue involving the misfiring of your engine should be dealt with immediately and always at the hands of a professional mechanic. Luckily, if you’re a BMW owner in the Canoga Park, Woodland Hills, San Fernando Valley, Los Angeles County, or surrounding areas of California, high-quality, knowledgeable auto repair is just around the corner. We are specialists in automotive German engineering. We will have you back on the road in no time.