The normal idle speed of most cars is between 700-800 rpm, and there are also some cars that are lower or higher. If the idle speed of the car is abnormal, it must be a malfunction and needs to be checked in a timely manner. Otherwise, either the fuel consumption will increase, the engine will stall, or the comfort will deteriorate. When the car has traveled more kilometers and has a longer age, abnormal idling is often encountered. There are three common idle faults: unstable idle, high idle, and low idle. Below are the most likely reasons for these situations, and don't waste money on repairs.

    1. Unstable idle speed. In terms of idle speed, unstable idle speed is the most common fault, which can also occur when driving a car for 30000 to 50000 kilometers, and the engine speed fluctuates unstable. Severe shaking can be felt inside the car, and when opening the hood, the engine also shakes. The common reason is that the throttle valve is dirty, and simply cleaning the throttle valve can solve the problem. There are two things to pay attention to. Many repair shops, in order to solve this problem, may not only ask the car owner to clean the throttle valve, but also clean the fuel injector, intake duct, carbon deposits in the cylinder, and so on, which will cost a lot of money. As for whether to clean, it needs to be determined through inspection. If it is really dirty, it needs to be cleaned; if it is not dirty, it does not need to be cleaned. The second point is that for cars with an idle motor, it is not enough to only wash the throttle valve. The idle motor should be removed for cleaning. The idle motor is the fundamental cause of unstable idle, and washing only the throttle valve without washing the idle motor is ineffective.

2. High idle speed. In most cases, the fault light will light up when the idle speed is high, and the car cannot drive normally. Whether in automatic or manual mode, it is difficult to start smoothly and control the low speed. The most common reason for high idle speed is air leakage in the intake pipe, such as a vacuum pipe falling off or breaking, or the intake pipe clip not being tightened, in short, there is air leakage. It is also possible that the throttle valve or idle motor is broken and needs to be replaced. If the throttle valve was cleaned by oneself, then high idle speed is normal, and the computer needs to be re matched to restore normal operation.

      3. Low idle speed. This fault is not very common. If it occurs, either there is a lot of carbon buildup on the throttle valve, or the throttle valve is also broken. It is common to encounter situations where the throttle valve accumulates a lot of carbon, not only due to low idle speed, but also due to the inability to start the engine directly. It is necessary to step on the accelerator to start the engine, which is an obvious phenomenon of a dirty throttle valve. So if you encounter a vehicle that cannot start, don't keep starting it. You should step on the accelerator while starting it, which can eliminate the problem of starting due to carbon buildup.

How to know if the idle speed of the car is normal? When starting a fire, observe the idle speed of your car more often. It is normal for a cold car to have a slightly higher idle speed because there is a warm-up process. When the water temperature is normal, the idle speed will remain stable at a certain value. If it is too high or too low, it is abnormal. In fact, abnormal idling can also cause malfunctions, and unstable idling can cause the vehicle to feel severe shaking; High idle speed will light up the fault light, and the engine noise will also increase, making it difficult to control starting; If the idle speed is low, it is easy to stall, and it is difficult to start the engine after stalling. Without looking at the instrument panel, it is possible to identify issues with idle speed solely through these phenomena. If these phenomena are not present, it indicates that idle speed is normal.

From: WONDEE Autoparts

2023-12-22