What if the modern Tucson is noisy?

It was last Wednesday that a modern Tucson came to the factory and suddenly the sound of the exhaust pipe could be heard far away. Just like shooting, when you are close to the car, you can feel the engine speed rising and falling, as if someone stepped on the accelerator and released it. This car owner has a high turn-back rate on the road and needs to be checked by the master.

After receiving the car, the master sat in the car first, and the speed of the instrument engine was particularly unstable. It is indeed high and low, and the instrument has a faulty light. As shown in the following figure, the vehicle mileage has exceeded 200,000 kilometers, and the vehicle age is 1 1 year.

Opening the hood, the master found the problem at once. As shown by the orange arrow in the figure below, the intake pipe in front of the throttle is broken, and its air flow sensor is still in front of the broken intake pipe!

The green arrow in the figure below indicates the position of the air flow sensor, and the orange arrow indicates the position of the throttle. The trachea connected with it is damaged and leaked.

The air quantity detected by the air flow sensor is seriously inconsistent with the actual air quantity entering the engine, and the data received by the engine computer is wrong, which leads to the computer always adjusting the fuel injection quantity incorrectly, resulting in unstable idle speed and abnormal acceleration of the engine.

At this point, the master unplugged the air sensor. As shown by the green arrow in the figure below, the plug of the sensor has been unplugged, and the engine idle speed is not as high and low as before, but remains high.

Why is this happening? The master said that after unplugging the sensor, the sensor would not work. The computer will only adjust the idle speed of the engine according to a wrong stable signal, and the idle speed is stable; If the plug is plugged in, this sensor will work, but it will always give the engine the wrong signal, and the engine idling is unstable.

Because the owner was in a hurry, the master's solution at that time was to unplug the airflow sensor. Although the idle speed of the engine is still high, at least it won't go up and down, and the sound of the exhaust pipe basically disappears, so there will definitely be no turning back when driving on the road. At the same time, with the consent of the owner, the master ordered the goods: a new intake pipe.

The next day, the new intake pipe arrived and the owner came to replace it. As shown in the figure below, compare the new and old intake pipes. Note the contrast between the green area and the orange area. The old intake pipe is seriously aging.

After installing the intake pipe in a hurry, the master started the engine and found that the idle speed of the engine was much more stable than before, but it was still high and abnormal. When the intake pipe was removed for inspection, it was found that the throttle valve was dirty, and the idle motor on the side was particularly dirty. They have a great influence on the idle speed of the engine, so the master decided to clean it.

Cleaning the throttle is simple. This time we only know the cleaning of idling motor. As shown below, this is the installation position of the idle motor, which has been removed by the master.

Speaking of this, some riders may still have questions. What is the function of idle motor? The master said that the main function of idle motor is to control air intake when the engine is idling. As shown by the green curve in the figure below, this air passage is directly connected in front of the throttle. When idling, the idle motor can be used to adjust the air intake of the engine.

If the idle motor is too dirty, the amount of air entering the engine at idle speed will be abnormal, the computer can't adjust the fuel injection normally, and the engine will shake. Obviously, not only the disassembled idle motor is dirty, but also its installation position is dirty, which is basically a mixture of oil vapor and dust. As shown below, the master is cleaning up the silt at the installation location.

As shown in the following figure, there is also a lot of sludge and dust in the idle motor, which will seriously affect the air intake at idle speed, and then cause engine jitter.

As shown below, the master is cleaning the sludge inside the idling motor with cleaning agent. The sludge sticks tightly and is difficult to clean. At present, there is basically no idle motor in the engine, and the idle speed is directly controlled by the throttle.

When the master installs and cleans the idle motor and throttle, connect the computer to delete the fault code, and then start the engine. The idle speed is stable, the operation is normal, and the exhaust pipe noise basically disappears. The owner is very satisfied with the maintenance result.

This is the process of master maintaining modern Tucson. The reason for the failure is that the intake pipe is aged and damaged, which leads to abnormal air intake, unstable engine idle speed, and the idling motor and throttle valve have not been cleaned for a long time, further aggravating the unstable idle speed. Cheyou have a brief understanding of this maintenance case, hoping to help Cheyou.

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