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List of the contents of this article:

• 1. What is the reason for the sudden high and low engine speed
• 2、What are the reasons for the sudden high and low idle speed of the car
• 5, What is the reason for the unstable idle speed of the engine?

What is the reason for the sudden high and low engine speed

gas distribution timing failure. The gas distribution phase is not accurate, the timing belt is installed incorrectly, the intake and exhaust valve is too carbonized, the valve spring is broken, etc., the air intake of each cylinder is different, and the idle speed will be unstable.The ternary catalyst is blocked. The blockage of the ternary catalyst will not only have unstable idle speed, but also lead to insufficient power. Fuel injector failure.

If the engine speed is high and low when the car is hot, there must be a problem. The reasons are as follows: 1. There is too much carbon in the throttlum. Inlet manifold or various valve leaks. This kind of failure also affects the quality and combustion effect of the fuel mixture.

The engine has serious carbon accumulation. The most common cause of idling jitter is excessive carbonisation of the throttle valve or fuel nozzle.

Another reason for the sudden high and low engine speed is the failure of the electronic control module (ECM). ECM is responsible for monitoring and controlling the operation of the engine. When ECM fails, it may cause engine speed instability.

The reason why the tachometer is high and low at low speedAs follows: The charging line is faulty. The failure of the charging line may be caused by generator failure, battery voltage sensor failure, loose battery pile head and other reasons. Because when the vehicle is running, the generator needs to charge the battery.

High-speed engine speed suddenly high and low

Solution: Replace the empty air filter. Low ignition energy: When the vehicle is cold start, the internal temperature of the engine is not enough. When the vehicle is cold start, the fuel injector injects more gasoline to meet the power needs. Fuel requires high ignition energy, and a large gap in the spark plug will lead to a low ignition energy, which in turn affects the power and makes the vehicle shake.

It may be caused by the failure of the charging line. The failure of the charging cable may be caused by generator failure, battery voltage sensor failure, loose battery pile head and other reasons.The main reasons why the engine speed fluctuates up and down during driving are as follows: there is a problem with the charging cable.

If the engine speed is high and low when the car is hot, there must be a problem. The reasons are as follows: 1. There is too much carbon in the throttlum. Inlet manifold or various valve leaks. This kind of failure also affects the quality and combustion effect of the fuel mixture.

The throttle valve is abnormal. The function of the throttle valve is to detect the opening of the throttle valve and control the injection volume. When the throttle valve is abnormal, it will cause the engine intake to change, resulting in a sudden high and low engine speed. The battery is abnormal. Because the vehicle is driving, the engine will charge the battery.

Another reason for the sudden high and low engine speed is the failure of the electronic control module (ECM). AndCM is responsible for monitoring and controlling the operation of the engine. When ECM fails, it may cause the engine speed to be unstable.

Engine speed is unstable and high and low, which may be the generator Obstacle causes

1. Low-speed driving speedThe reasons for the high and low of the meter are as follows: the charging line is faulty, and the failure of the charging line may be caused by generator failure, battery voltage sensor failure, loose battery pile head and other reasons. Because when the vehicle is running, the generator needs to charge the battery.

2. It may be due to generator failure, battery voltage sensor failure, loose battery pile head, etc. According to the driving encyclopedia, the rotation speed of 08 Tianli running to 100 yards may be due to generator failure, battery voltage sensor failure, loose battery pile head, etc.

3. Insufficient idle power generation of the alternator leads to electromagnetic interference. Insufficient idle power generation will lead to distortion of the nonlinear signal of the alternator. The electromagnetic interference generated will affect the fuel injector, resulting in slight shaking of the engine during idling, and returning to normal after starting.

4. The reason why the car tachymeter suddenly rises and falls is: the failure of the charging line: the failure of the charging line is caused by the failure of the generator, the failure of the battery voltage sensor, the looseness of the battery pile head and other reasons; the fault of the throttle valve: the failure of the throttle valve is the failure of the throttle position sensor or the throttle control Motor failure.

5. Speed adjuster failure The elasticity of the speed regulation spring is weakened. Insufficient spring elasticity will reduce the sensitivity of the speed regulation of the speed reducer, and the stability range of the diesel engine speed will increase, which will be high and low. At this time, the speed regulation spring should be replaced.

6. The reasons for the unstable idle speed of the car are the blockage of the idling air volume hole, the poor operation of the idling device, the weak spark of individual cylinder spark plugs, the loose sealing of individual valves, leakage of the intake manifold, too early or too late ignition time, improper idling adjustment, etc.

What are the reasons why the idling speed of the car is suddenly high and low

1. Air flow sensor problem; intake manifold leakage; carbon tank solenoid valve is often open; crankcase forced ventilation valve is often open; air filtration blockage. The reasons for the high and low idling speed of the car may be: excessive carbon accumulation of the throttle valve, the leakage of the intake manifold or various valves.

2. The sudden high and low idle speed may be caused by the following reasons: idle control valve failure: the normal idle speed of the electric injection engine is determined by the idle speed control valve.

3. Water temperature sensor failure: When the engine is idling, the electric control unit of the car will read the hot state of the engine according to the signal input from the coolant temperature sensor, that is, the water temperature sensor, and correct the fuel injection volume.If the water temperature sensor is poor, the output signal is not accurate, resulting in too low idle speed, lack of fire and slow operation.

What is the reason for the unstable idle speed of the engine?

Water temperature sensor failure: When the engine is idling, the automobile electronic control unit will judge the thermal state of the engine according to the signal input by the coolant temperature sensor, that is, the water temperature sensor, and correct the fuel injection volume. If the water temperature sensor is poor, the output signal is not accurate, resulting in too low idle speed, lack of fire and slow operation.

The reasons are as follows: the stolen goods produced in the air and the oil sludge generated by gasoline are easy to cause the vehicle's throttle valve to be too dirty and the idle motor does not work smoothly. Too much carbon accumulation is easy to cause the valve closure to be loose, the fuel injection nozzle is not atomized well, and the combustion is insufficient.The exhaust pipe is blocked, resulting in poor exhaust.

The idling speed may be caused by the following reasons: idle control valve failure: the normal idle speed of the electric injection engine is determined by the idle speed control valve.

The reason why the engine idle speed is unstable and high and low: the throttle valve oil storage and the throttle valve accumulates carbon, the intake duct is too dirty, and the intake duct is blocked will cause idling pulling, and there is carbon or oil in the throttle, which is the most common cause of idle instability.