Is it normal for vv7 engine to make abnormal noise?

Abnormal sound of vv7 engine is normal. Because the engine is a direct injection engine, the direct injection engine will directly inject into the cylinder when injecting fuel. The direct injection engine will have a high-pressure pump with a high-pressure fuel injection pump, which will make abnormal noise when working. This is a normal phenomenon. Causes of abnormal sound of automobile engine: foot glue aging: foot glue is a rubber block between engine and frame. Its function is to reduce the vibration and buffer when the engine works and fix the engine. Once these feet are aged or loose, the engine will shake and produce abnormal noise. Engine cylinder missing: one or more cylinders of the engine are not working normally, the exhaust gas flow from the automobile is obviously intermittent, and the exhaust pipe is seriously shaken. This phenomenon is closely related to the failure of ignition coil. Due to poor lubrication conditions, the piston and cylinder wall are excessively worn, and the clearance fit tolerance between the piston and cylinder wall is beyond the normal range. This situation is more obvious when the engine is running and the piston collides with the cylinder wall at idle speed or low speed. When the engine mixture is too rich, the engine is not easy to start; It is difficult to accelerate after starting, and the engine runs unsteadily; The exhaust pipe emits black smoke, and the engine is accompanied by sudden abnormal noise. Diagnostic method of engine abnormal sound: artificial intuitive audition method: mainly with the help of stethoscope, flameout test, combined with changing throttle opening, etc. Listen and observe the change of abnormal sound with your ears and eyes. In the process of listening, we should also observe the changes of smoke color and smoke quantity in the exhaust pipe and the working conditions of various instruments in time. Instrumental diagnosis method: As the noise, sound pressure and amplitude of various abnormal sounds and vibrations of the engine are different, as long as the friction pair of the engine is worn, the fit gap is increased or a certain part is loose, abnormal sounds and vibrations will be generated, forming a unique sound level, sound pressure and amplitude, which will be reflected by the instrument.