The problem of the engine is reflected by abnormal noise

1. Engine knock. It is a sound similar to metal knocking, which can also be called cylinder knocking. There are three causes of failure:

a. The fuel is unqualified, and inferior fuel or fuel with low grade is used.

b. If the engine timing control is wrong, such as the ignition advance angle is too large, readjust the timing.

c. If there is too much carbon deposit inside the engine, you can try the carbon deposit cleaning effect through disassembly free cleaning or high speed, otherwise you can only clean the carbon deposit by disassembling the engine. Generally, more serious cases are often accompanied by more serious oil burning.

2. Abnormal valve noise. The engine "clatters" after landing. It's the sound of the valve, especially after the car is cold. It's because the oil pressure hasn't gone up at this time and the valve hasn't been lubricated in place. It'll be fine after a while. This will happen if your car is parked for a long time.

If the sound keeps ringing, it may be excessive valve clearance or oil leakage at the camshaft. It is necessary to adjust the valve clearance or replace the relevant oil seal. It is also possible that the oil used is unqualified. For example, vehicles with high mileage use thinner oil, which can be eliminated by changing the oil (for how to select the oil, please refer to how to select the oil correctly).

3. Engine "backfire" fault. There is a "poof poop" sound when the car decelerates and receives oil. It may be the engine "backfire" fault, that is, the usual engine "shooting". Excessive valve carbon deposition or wrong valve timing will produce abnormal noise. Clean the valve carbon deposition or adjust the valve timing.

4. If the engine is short of cylinders and one cylinder does not work, the engine will be unbalanced and produce abnormal noise. In addition, it is accompanied by severe engine shaking, insufficient power and other faults, which may be the faults of ignition module, spark plug and fuel injection nozzle. Replace the corresponding accessories.