(1) The relationship between abnormal noise and engine speed The existence of the most common abnormal noises in engines depends on the condition of the engine speed. ① Abnormal noise only exists at idle or low speed. The reasons for the noise include: too much clearance between the piston and the cylinder wall; too tight mounting of the piston pin or too tight mounting of the connecting rod bearing too much clearance between the pusher and its valve guide hole; cam profile; sometimes the starter latch is loose and the pulley is damaged (squealing visible when changing speeds). ②The sound is chaotic when maintaining a certain speed, and short-term sounds occur one after another during rapid deceleration. The reasons for the noise are: the camshaft timing gear is cracked or its fixing nut is loose; the crankshaft is broken; the piston pin bushing is loose; the axial play of the arcamber is too large or its ring is loose. ③ Abnormal noise occurs when the engine accelerates quickly, and the sound still exists when the engine runs at high speed. The reasons for the noise are: the connecting rod bearing is loose, the bushing is burned, or the size does not match and rotates; the crankshaft bearing is loose or the bushing is burned; broken. (2) The relationship between abnormal noise and load. Many abnormal engine noises have an obvious relationship with load. When diagnosing, the cylinder-by-cylinder load unloading method can generally be used for testing. The double-cylinder ignition method is used to relieve the load of one or two cylinders to identify the relationship between abnormal noise and load. ① The fire in a certain cylinder is cut off, and the abnormal noise disappears or is reduced. The reasons for this noise are: knocking of the piston on the cylinder ; connecting rod bearing clearance; leaking broken piston pin; ② If the fire in a certain cylinder is cut off, the sound will increase, or there will be no sound at that time instead of no sound at the beginning. The reasons for the noise are: the copper sleeve of the piston pin is loose; the conicity of the piston skirt is too great; the connecting rod bearing cover mounting bolts are too loose; or the connecting rod bearing is too loose; the alloy melted; The steering wheel mounting bolts are too loose. ③ The abnormal sound of two adjacent cylinders cutting the fire is reduced or disappears. The reasons for the noise are: a loose crankshaft bearing. (3) The relationship between abnormal sound and temperature ① It makes noise at low temperatures. As the temperature increases, the sound decreases or even disappears. The reasons for the noise are: the gap between the piston and the cylinder wall is too large; the piston is not aligned in rison the depth and width of the main bearing oil groove; engine oil pressure is low and lubrication is poor; . ② There is a sound when the temperature increases, and the sound decreases or disappears when the temperature drops. Reasons for noise include: premature ignition caused by overheating; the long and short axes of the piston skirt ellipse are in opposite directions; the ovality of the piston is small and the gap between the piston and the cylinder wall is too small; is distorted; the gaps between the piston rings are too small. (4) The relationship between abnormal noise and engine duty cycle. The abnormal failure of engine noise is often obviously related to the engine duty cycle. Particularly, the abnormal noise of the crank rod mechanism and valve system is related to the abnormal noise. work cycle. For a four-stroke engine, any noise provoked by the crank connecting rod mechanism is output twice once when the engine is running; all sounds caused by the valve mechanism are emitted once when the engine is running; ① The causes of abnormal noise caused by the crank-connecting rod mechanism include: the piston hits the cylinder wall; knocking noise from the piston pin and connecting rod bearing are too loose; the ring is leaking. ② The causes of abnormal noise caused by the valve mechanism include: excessive valve clearance; excessive clearance between the lifter and its guide hole; loss of excessive clearance between the valve stem and camshaft timing gear diameter; towards breakage;Valve seat ring is loose; the valve is stuck and cannot be closed. ③If the abnormal sound has nothing to do with the work cycle, you should pay attention to the area where it makes the sound. Usually the noise caused by thecart which has nothing to do with the duty cycle is mainly a fault in the engine accessories; If there is a continuous metallic friction noise coming from the machine parts that has nothing to do with the work cycle, this may indicate that some rotating parts are defective. (5) The relationship between abnormal noise and engine parts When abnormal noise occurs in the engine, it will inevitably produce a certain degree of vibration. The characteristics and location of the vibration can help diagnose the cause of the abnormal noise.
Hello! For the problem you reported, we recommend observing it and seeing if it is an occasional problem or if it happens all the time. If it was an accident, it may have something to do with your current driving style. If it continues, you can go to the 4S store to check. The engine clicking noise may be thenoise near the pulley or valve may be abnormal. The suggestions above are for reference only.