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60 Vehicle Regular Repair Fault and Solution Part 2

Nov 12, 2021

11. The vehicle shakes at high speed

 

Fault determination: true fault.

 

Cause analysis: when the vehicle runs normally to about 96km / h, the whole vehicle jitters. When the vehicle speed is reduced, the phenomenon disappears. If the jitter occurs again when it accelerates to about 90km / h, it indicates that there is a fault in the vehicle chassis. The fault causes are: tire dynamic balance misalignment; The front and rear suspension, steering, transmission and other mechanisms are loose; Front wheel alignment. Wheelbase misalignment; Half shaft clearance is too large.

 

Solution: eliminate the above faults in time to avoid a vicious circle and cause other faults.

 

12. When the car turns, the big turn of the steering wheel turns into a small turn, and the small turn of the steering wheel turns into a big turn

 

Fault determination: true fault.

 

Cause analysis: the former is called understeer and the latter is called oversteer, which indicates that there is a problem with the steering system. There is also a turning phenomenon,

 

At first, it was understeer, but in the middle, it became oversteer and turned sharply to the inside. This is the most dangerous reversal phenomenon, prone to accidents.

 

Solution: this situation only occurs on individual rear engine vehicles. Remember to repair it in time.

 

13. It is difficult to start the engine cold. After starting, the engine vibrates and then tends to be stable. The engine starts shaking at medium and low speed and improves at high speed.

 

Fault determination: true fault.

 

Cause analysis: it may be spark plug failure or premature ignition time. If it is not the spark plug fault, it can be judged that the ignition time is too early.

 

Solution: in case of the above faults, go to the repair shop for repair in time.

 

14. The engine runs unsteadily, often accompanied by "sudden" sound. When accelerating, the engine power is insufficient, the sound of "Peng Peng" shooting is emitted from time to time, and the exhaust pipe emits black smoke.

 

Fault determination: true fault.

 

Cause analysis: it is possible that the spark plug talks or the ignition time is too late. If the ignition time is too late and the engine piston is very close to the top dead center, the spark plug starts ignition. The mixture combustion lags behind and the combustion is incomplete. When the piston goes down and even when the exhaust valve is opened, the mixture is still burning. The expansion of combustion chamber volume and gas lag expansion lead to low cylinder pressure and engine power decline. Part of the combustion expanded mixture may also return to the carburetor through the inlet valve, resulting in backfire and violent "Peng Peng" sound. The incomplete combustion mixture emits black smoke from the exhaust pipe.

 

Solution: go to the repair shop for repair in time.

 

15. When the temperature is low in winter, the car will be parked for a long time and it is difficult to start the engine

 

Fault determination: false fault.

 

Cause analysis: due to the low temperature, the gasification rate of fuel oil decreases, and the mixture becomes lean and difficult to burn, resulting in difficult starting. At the same time, it is difficult to start due to low temperature, increased oil viscosity and increased engine running resistance. In addition, the chemical reaction of battery electrolyte is slow, resulting in insufficient power output during starting. Insufficient starter power and ignition voltage make it difficult for the engine to start.

 

Solution: warm up the engine before starting the car in cold season. The battery can also be preheated as needed to enhance the power of the battery and increase the starting current and ignition voltage.

 

16. The steering wheel swings when the vehicle is running empty or heavy, and the swing is more serious when driving on a flat road

 

Fault determination: true fault.

 

Cause analysis: it is generally caused by the toe in not meeting the technical standards and the excessive wear of the tie rod ball joint and the internal fit clearance of the steering gear, or the loose fixing bolts of the steering gear and the excessive wear of the steering knuckle pin and bushing.

 

Solution: go to the repair shop for repair in time.

 

17. When the vehicle encounters a fault during driving, it will cause the steering wheel to swing, and the swing is more serious when the vehicle is loaded

 

Fault determination: true fault.

 

Cause analysis: generally, it is caused by uneven wear of front wheel tires, uneven use of newly repaired tires or cushion tires and deformation of steel ring. Because when the wheel speed is fast, the torque driving the steering wheel mainly comes from the deflection of the tire or steel ring. When the swing difference of tire or steel ring exceeds 3mm, the yaw moment can drive the steering wheel to swing left and right.

 

Solution: go to the repair shop for inspection and replace the Chemical tire or steel ring as appropriate.

 

18. When driving at high speed on a good road, the steering wheel swings when the vehicle is heavy and empty. The swing is serious when the vehicle is heavy, and the faster the speed is, the more serious the swing is

 

Fault determination: true fault.

 

Cause analysis: it is generally due to the loose connecting bolts between the brake drum and the wheel hub, the loose wheel hub bearing hole and the deviation of the brake drum boring from the center, resulting in different thickness of the brake drum and imbalance.

 

Solution: go to the repair shop for repair in time.

 

19. There is some jitter when releasing and closing the clutch

 

Fault determination: true fault.

 

Cause analysis: it indicates that the clutch fork, release bearing, pressure plate and friction plate are seriously worn, the transfer case is free of oil, the front telescopic sleeve and its bearing of the rear transmission shaft are seriously worn out and black, and the oil seal of the rear cover of the transfer case has been burnt out. There are only two reasons for the above situation. One is the problem of positioning between transmission shafts, resulting in shaft non parallelism; The other is that the clearance between shafts is too large.

 

Solution: go to the repair shop for replacement and repair in time.

 

20. When unscrewing the radiator cap, it is found that there are always some oil stains floating on the water, and there is water when changing the oil

 

Fault determination: true fault.

 

Cause analysis: the engine has two major circulation systems, one is the coolant circulation system and the other is the lubricating oil circulation system. The two systems are not connected with each other. If there is oil in the water or water in the oil, there is a problem in an isolated place in the two circulating systems“ "Oil into water" and "water into oil" are two different faults“ "Water in oil" is the fault of the engine body itself, while "water in oil" is mostly caused by engine parts, and its fault nature is different.

 

Solution: go to the repair shop for replacement and repair in time.