Suitable for collecting car maintenance knowledge Teach you to identify fault

1, the exhaust pipe emits black smoke

Fault determination: true fault.

Analysis of the cause: It indicates that the mixture is too rich and the combustion is not complete. The main reason is that the automobile engine is overloaded, the cylinder pressure is insufficient, the engine temperature is too low, the carburetor is improperly adjusted, the air filter is clogged, the individual cylinders are not working, and the ignition is too late. When excluding, check whether the choke valve is completely open and repair if necessary. After the flameout, look at the main nozzle from the carburetor port. If there is oil injection or dripping, the oil level of the float chamber is too high and should be adjusted to the specified range. , tighten or replace the main hole; the air filter is clogged and should be cleaned, dredged or replaced.

2, the exhaust pipe of the vehicle emits blue smoke

Fault determination: true failure.

Analysis of the cause: It is because a large amount of oil enters the cylinder and cannot be completely burned. Remove the spark plug and you will find serious carbon deposits. Check whether the oil level of the oil dipstick is too high; whether the clearance between the cylinder and the piston is too large; whether the piston ring is reversed; whether the intake valve is worn or the seal is damaged; whether the cylinder gasket is ablated, etc., if necessary, repair it.

3, the vehicle exhaust pipe emits white smoke, the cold car is serious, after the hot car does not take white smoke

Fault judgment: false fault.

Analysis of the cause: This is because the gasoline contains water, and the engine is too cold. At this time, the fuel entering the cylinder is not completely burned, resulting in fog or water vapor to form white smoke. When the car is first launched in the winter or rainy season, white smoke can often be seen. It doesn’t matter, once the engine temperature rises, the white smoke will disappear. This condition does not have to be overhauled.

4, the engine noise is large, when the vehicle is stepping on the accelerator pedal, there is “long, long”; abnormal sound, there is vibration in the engine compartment

Fault determination: use type fault.

Analysis of the cause: Lifting the vehicle, you can see that the bottom guard of the engine has bumps. If the road surface has obstacles and forcibly passes, the engine bottom guard will be bumped. After the bottom guard is deformed, the distance from the engine oil sump becomes closer. If the distance is too close, when the oil sump collides with the bottom guard when accelerating, an abnormal sound is emitted and the vehicle body vibrates. Therefore, you must carefully observe the road surface during driving, and do not cause the bottoming phenomenon to occur. Treatment method: remove the bottom guard and flatten it.

5, the steering wheel of the vehicle is always not right, one will turn to the left, one will turn to the right, erratic

Fault determination: true fault.

Analysis of the cause: This is due to the complete damage of the rubber stop block fixed in the groove of the steering gear. After the new limit block is installed, the fault completely disappears.

6. Every time the air conditioner is turned on, the air outlet has a very bad smell, which is more serious when the weather is wet.

Fault judgment: maintenance fault.

Analysis of the cause: The principle of refrigeration of air conditioners is to rapidly evaporate heat through the refrigerant, so that the temperature of the air flowing through it drops rapidly. Due to the low temperature of the evaporator and the high air temperature, water molecules in the air will condense into water droplets on the evaporator, and dust or clothes in the air, small fluff on the seat, etc., easily adhere to the condenser. The surface, which causes mold, bacteria will multiply. Such long-term inhalation of air by the human body will affect the health of the driver and the passenger. Therefore, the air-conditioning system should periodically replace the air-conditioning filter to clean the air passage.

7, the windshield is not clean when it is raining

Fault judgment: maintenance fault.

Analysis of the cause: It is good to use the wiper when it is not raining very much, but when the light rain starts the wiper, it will be found that the wiper will leave uneven marks on the glass surface. Sometimes it will get stuck on the glass and cause poor line of sight. This situation indicates that the wiper blade has hardened. The wiper is converted into a one-to-one motion by the connecting rod by the rotational energy of the motor, and the force is transmitted to the wiper arm.

When the rubber part of the wiper is hardened, the wiper will not fit snugly against the glass surface, or if the wiper blade is scratched, it will cause unevenness in the wiping and form residual dirt. The replacement of the wiper or wiper film side is simple. However, when replacing, it should be noted that the installation method and length of the wiper are different depending on the model and year. Some wiper film replacement is simple. However, when replacing, it should be noted that the installation method and length of the wiper are different depending on the model and year. Some wipers only need to replace the rubber sheet, and some wipers need to be replaced as a whole.

8, the vehicle is noisy

Fault judgment: false fault.

Analysis of the causes: Whether it is high-end cars, low-end cars, imported cars, domestic cars, new cars, old cars, there are different levels of noise problems. The interior noise mainly comes from five aspects: engine noise, wind noise, body resonance, suspension noise and tire sound. When the vehicle is running, the engine runs at high speed, and the noise is transmitted into the car through the firewall, the bottom wall, etc.; the body resonance generated by the car driving on the bumpy road, or the window that is opened when the vehicle is running at high speed, cannot become resonance.

Because of the narrow space inside the car, the noise cannot be absorbed effectively, and sometimes it will resonate in the car. During driving, the noise generated by the car’s suspension system and the noise generated by the tires are transmitted to the vehicle through the chassis. The noise generated by different suspension methods, different tire brands, different tire patterns, and different tire pressures are different; the body shape is different and the driving speed is different, and the wind noise generated by the body is also different. In general, the higher the driving speed, the greater the wind noise.

9, the engine temperature is suddenly too high during operation

Fault determination: true fault.

Analysis of the cause: If the car is in operation, the coolant temperature gauge indicates that it will reach 100 °C quickly, or when the cold car is started, the engine coolant temperature will rise rapidly to boiling, and the coolant will be replenished. After turning to normal, but the engine power dropped significantly, indicating that the engine mechanical system has failed. Most of the causes of such failures are: the water system is seriously leaking; the cylinder liner of the water jacket and the cylinder is damaged; the main valve of the thermostat is detached; the fan belt is loose or broken; the pump shaft and the impeller are loose; the fan clutch is working. bad.

10, the engine oil pressure indicator will light when the car accelerates

Fault determination: true and false faults coexist.

Analysis of the cause: The oil lamp lights up in both real and virtual situations. The so-called real, that is, the oil pressure is really low, as low as the warning level of the indicator light, indicating that the lubrication system is faulty and must be excluded. The so-called virtual, as doubtful, the oil lubrication system is not faulty, but the oil pressure indicator system has failed, and the indicator light is erroneously lit. Although this kind of failure will not affect the normal operation of the engine, it should also find the root cause in time. Usually, the possibility of actual illness is large, and it should be used as the main idea for judging the fault.
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