What is the reason for the exhaust pipe jitter?

First of all, the exhaust pipe and the engine are soft connected, which may be caused by the damage of the soft connection after the car has been used for a long time. Secondly, the connection between the exhaust pipe and the frame is fixed by several rubber rings, so it can be checked whether the rubber rings are damaged or whether the rubber is aging; Finally, there are seals between the exhaust pipe and the flexible joint and between the flexible joint and the engine. You can check whether the seal is damaged.

Common fault points of unstable idle speed of automobiles are as follows:

1. The intake manifold or various valves leak. When the intake of the engine is incorrect, the mixture will be too rich or too lean, causing the engine to burn abnormally. Will lead to engine idling jitter.

When the position of air leakage affects the vacuum degree of the engine, the engine will shake violently, which has a great influence on the idle speed of the cold car.

Common reasons are: air leakage caused by aging of intake manifold gasket, damaged intake manifold or worn holes of other parts, vacuum tube plug falling off, EGR valve damaged and not closed properly, etc.

2. There is too much dirt on the throttle and air intake. Too much carbon and dirt are deposited in the throttle valve and the surrounding air intake, and the cross-sectional area of the air passage changes, which makes the control unit unable to accurately control the idle intake, resulting in the mixture being too rich or too thin and abnormal combustion.

The common reasons are: carbon deposition on the throttle, and oil pollution and carbon deposition on the air intake around the throttle.

3. Idle air actuator failure Idle air actuator failure leads to inaccurate idle air control.

The common reasons are: the throttle motor is damaged or stuck, and the throttle valve plate is stuck with carbon deposition.

4. The air intake misalignment control unit receives the signal from the wrong air flow sensor and sends out the wrong instruction, which leads to inaccurate air intake at idle speed of the engine and abnormal combustion of the engine due to abnormal concentration of mixed gas, which is the indirect cause of unstable idle speed.

Common causes are: air flowmeter or its line failure; Intake pressure sensor or its line fault; Poor contact of engine control unit harness or failure of engine control side itself.

It is recommended to check the above components when the vehicle is idling unsteadily.