The exhaust sound of BMW 325 becomes louder after washing.

After washing BMW 325, the exhaust noise becomes louder because the throttle valve needs cleaning.

As the earliest valve in the intake structure, the throttle valve is also the so-called throttle valve in the popular sense. Generally, it can be cleaned according to the specific mileage and environment, regardless of the age of the car. The front end of the throttle touches the air, and it is not easy to get dirty about 40 thousand kilometers. Cleaning once is more reasonable. On the other hand, ea888 engine with throttle a4l, whether it is the new third-generation mixed injection or the second-generation in-cylinder direct injection, has a large carbon deposit. This is an important thing to clean. Under normal circumstances, the amount of carbon deposition will be very high, around 20 thousand.