What is the reason for the abnormal sound of the exhaust pipe when the Jetta cool car starts

1) Whether the exhaust pipe connection is loose, 2) Whether the three-way catalytic converter is broken inside, resulting in abnormal noise when just landing or when accelerating sharply.

3) When the car is on in the morning, the vibration is relatively large, which will cause the exhaust pipe to shake violently, it is recommended to check the spark plug, and the idle motor, check the oil circuit, whether the engine carbon deposit is serious. See if there is a problem that causes the engine to shake when the car is cold, resulting in abnormal sound of the exhaust pipe.

The exhaust pipe is: 1) a part of the engine exhaust system, the exhaust system mainly includes the exhaust manifold, the exhaust pipe and the muffler, generally the three-school catalytic converter to control the emission of engine pollutants is also installed in the exhaust system, the exhaust pipe generally includes the front exhaust pipe and the rear exhaust pipe.

2) When the engine is ignited, the piston starts radial force travel, and the exhaust valve opens before the piston reaches the bottom dead center. At this time, the back pressure in the pipe will block the exhaust gas from rushing out, so that the mixture can be completely combusted. However, if the back pressure is too strong, the exhaust gas will not be completely discharged from the cylinder, resulting in the combustion of the exhaust gas and the mixture gas to reduce the combustion efficiency, of course, the most direct is to trigger the horsepower output.

3) Its advantages: low noise, good torque at low speed.

Disadvantages: The exhaust gas cannot be discharged quickly at high speed, which affects the power output of the engine and the volume is low.

According to what you said, vehicles with oil burning will have different degrees of "blue smoke" symptoms from exhaust gas, and the oil consumption will increase significantly, and the oil will have to be replenished in a short period of time. The phenomenon of burning engine oil in the vehicle will lead to an increase in carbon deposits in the combustion chamber, a decrease in the economy and power of the vehicle, and excessive exhaust emissions. The poor sealing of the cylinder is the main cause of oil burning.

The poor sealing of the cylinder is mainly due to the excessive matching gap between the piston and the cylinder wall, the improper installation of the piston ring or the poor sealing, and the oil on the cylinder wall enters the combustion chamber, causing the phenomenon of burning oil. In addition, poor sealing performance of the valve seal, damage to the crankcase vent valve, or crankcase vent blockage will cause the oil to enter the cylinder with the crankcase gas to participate in combustion. At the same time, the vehicle needs to be cleaned for carbon deposits.

Possible reasons for the abnormal noise of Jetta cold starting:1. Whether the oil has not been changed for a long time is caused by the deterioration of the oil quality.

2.It may be caused by the aging of the belt. 3.

Check whether the exhaust pipe is leaking, whether the engine is missing, and whether the engine has resonance.

Many new owners of Volkswagen Jetta will suspect that the car engine has an abnormal sound when the front cover is idle and opened. If you can't hear this sound in the car, don't make it too loud, it's usually the sound of the valve or injector. The canister solenoid valve also has this sound, but the sound is relatively brittle.

There is a way to distinguish between them, which is to give some oil at idle and see if the frequency changes. If the frequency does not change, it is the sound of the solenoid valve, and if the frequency changes, it should be the abnormal sound at the valve. If you can't hear clearly in the nuclear Sakura car, it's not a big deal.

The car will have a corresponding click, one is the sound of the injectors working, one is the sound of the valve position, and there is a similar sound, which is the sound of the timing chain, but it is not the same as the click, and there is also a glagla sound. Generally, when a car starts cold, the engine will be a little louder than a hot car. As long as the sound is even, soft and not harsh, there is generally no problem.

This is because the gap between the cylinder wall and the piston is not yet optimally sized when the car is cold, and the lubrication of the oil is not sufficient. Usually, when the engine block temperature reaches around 95 degrees, the sound returns to normal.

Lower-profile about the question you asked, in general, three-way catalytic converters.

It is easy to damage the tail section of the exhaust pipe, if it is an abnormal sound inside the three-way catalytic converter, it means that the ceramic carrier during the catalytic period is broken, and the three-way catalytic converter needs to be replaced in time. If it is an abnormal sound in the tail section of the exhaust pipe, it means that the inside of the tail section of the exhaust pipe is falling off, and it is recommended that you go to the 4S store immediately.

Replace the tail section with a new one. Then there is a lack of accommodation is the entry of foreign objects into the tail section of the exhaust pipe, resulting in volcanic dismantling and idling. Information.

The fault phenomenon of black smoke is: when the engine is working, the exhaust pipe emits black smoke, and can smell the pungent gasoline smell, which is more obvious when accelerating. The cause of the failure may be: the mixture is too thick; The spark plug is not working well; Ignition is too late.

The cause of the failure may be: the oil level is too high; The cylinder compression pressure is lower than the specified value; The gap between the piston, piston and cylinder barrel increases.

2. The original fault phenomenon of white smoke is: when the engine is working, white smoke comes out of the exhaust pipe. The causes of the failure may be: the fuel contains moisture; There is moisture in the cylinder or muffler.

1. Abnormal sound of cold start.

Usually the car is parked for a period of time and then starts, and there is a relatively large vibration and abnormal sound of "da-da".

When the car is parked for a long time, the oil flows back to the oil pan, and the oil pump cannot immediately establish the oil pressure when the cold car starts, especially in the upper part of the engine, the valve is not sufficiently lubricated, and the hydraulic tappet and mechanical rocker arm fail to work normally, resulting in abnormal noise.

Solution: Normal phenomenon, don't pay attention to it, it will be fine in a while.

Second, the engine oil is not suitable.

The oil viscosity is too high, which will lead to insufficient lubrication during engine operation, resulting in friction and abnormal noise, which will occur after many riders maintain and replace different engine oils.

Solution: Change the right oil.

3. The tightness of the belt is not suitable.

If the belt is not tightened enough, it will make a squeaky and squeaky noise, which is particularly uncomfortable to sound.

Solution: Adjust the tightness of the engine belt.

Fourth, the engine "tempering" failure.

When the engine's valve has too much carbon or the timing is not adjusted correctly, the engine will have a "poof" sound.

Solution: Clean the valve carbon deposit and adjust the valve timing.

Regarding the question you asked, the control characteristics of the electric injection engine are determined, the cylinder is first injected and then ignited every time it works, and the ignition is cut off immediately when the engine is extinguished, but the gasoline sprayed out by the working cycle can not be **, can only be attached to the intake valve and the combustion chamber wall, the gasoline is easy to volatilize, but the wax and gum in the gasoline are left, and the wax and gum in the gasoline accumulate more and more thickly, and the carbon deposit is formed after repeated heating and hardening. There is also the possibility of using "high-grade and low-speed" bad driving habits; prolonged idling and low-speed driving; The use of gasoline that does not meet the requirements of purity and quality can lead to the formation of carbon deposits.

If you want to slow down the formation of carbon deposition, you must choose the gasoline suitable for the model according to the manufacturer's instruction manual, and the driving habits and conditions of use are also very important. Avoid long-term engine idling, long-term low-speed running vehicles, should often run at high speed, high-speed driving can make the mix fully combusted, improve fuel economy, and can reduce the generation of carbon deposits, restore the sensitivity of the oxygen sensor, clean the carbon deposits between the spark plug electrodes and on the surface of the three-way catalytic converter. There is no specific cleaning time, you can pay attention to check it during regular maintenance.

Some engine noises change with the condition of the vehicle, but the most noise comes from the engine's lubrication system. Mainly due to the nature of the oil and abnormal maintenance

1. Carbon deposits, solid carbon-like substances with large thickness in high-temperature areas such as cylinder heads, fuel injectors, and piston tops.

2. Paint film, the piston ring and piston skirt, due to high temperature and metal catalysis, the production of gum.

3. Oil sludge is formed with impurities entering the engine under low temperature and low pressure, which also has a certain relationship with crankcase ventilation, so it is necessary to replace the air filter regularly.

There is also the wear and tear of the engine will also increase the noise of the engine, for the noise when the air conditioner is turned on, the main ones are:

1. The increase of load, about this model will consume about 2 horsepower of engine power.

2. The work of the system, the operation of the electronic fan when the air conditioner is working.

It is recommended that you check whether the generator belt is aging and loose, the generator belt is stiff in the case of a cool car, if it is loose and will cause slippage, it is recommended that you adjust the tensioner first, if not, it is recommended to replace the belt. Secondly, check the starting motor, due to the cold weather, the front armature bearing is slow to return, there is a sound of teething, it is recommended that you check it.

The valve drum has pressure relief, and if the hot car does not sound, it can not be repaired, and it can be maintained on time [If you have a problem with the car, ask the car master. 4S shop professional technician, 10 minutes to solve. 】