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Analysis and treatment of common faults of engine
1. Fault classification: engine control circuit fault, engine itself fault and other external faults. Troubleshooting ideas: In principle, first troubleshoot the control circuit-then troubleshoot the engine itself-and then troubleshoot other external faults.
Second, the common fault phenomena and their analysis and treatment (the following is the process of sorting out the possible causes of different fault phenomena. The editor should try to list them in order according to the thinking process of troubleshooting, taking into account the technical ability of different maintenance personnel and their familiarity with different machines. , for maintenance personnel reference only):
1, difficult or unable to start. (For the reason of electrical control, see Electrical Fault, which is not described here. )
Cause analysis and treatment: (The first five items can be checked by operators themselves, and the following items need to be checked by personnel specially trained in engine)
A. the ambient temperature is too low. Treatment method: install a preheating device on the oil tank; Change fuel; Check the condition of preheating spark plugs.
B. the battery is dead or damaged. Disposal: Charge the battery or replace it with a new one.
C, starting motor failure. Cause: The starting motor has no action. Check whether the starting motor is energized. If there is power failure, check whether there is voltage in the external control circuit. If it is energized, check whether the connecting wire of the starting motor is loose or rusted (voltage standard: the measured voltage of 24V shall not be lower than 22. 18v). The starting motor still has no action, and it is judged that the starting motor is damaged. Treatment: The general damage of starting motor may be the damage of solenoid valve or the wear of motor carbon brush. Repair or replace the starting motor. On-site temporary emergency treatment method for damage fault of starting motor: manually pull up the stop solenoid valve to open it; Connect the control line stub of the electromagnetic clutch with the power line stub of the starting motor for 2~3 seconds with a connecting wire or a long screwdriver, and immediately drive the engine to disconnect after starting (this method is harmful to the engine due to improper operation, so it is used in an emergency).
C, lack of fuel leads to failure to absorb fuel or problems with fuel quality and oil supply pipeline. Treatment: (1) Check the oil level, and check whether the exhaust hole of the oil tank is blocked, resulting in the oil suction not being in place. (2) Check whether the pipeline leaks. (3), check whether there is dirt in the pipeline. (4) Whether the sealing ring of the fuel filter element is damaged and whether the cooperation is correct. 5], fuel hose for damage, aging and folding phenomenon. [6], diesel pipe hollow screw copper pad deformation. Once, the diesel filter was dirty.
D, oil viscosity problem. Treatment: Check whether the engine oil meets the standard. Whether to change the appropriate oil due to seasonal changes.
E. Whether the adjusting toothed bar of the fuel injection pump is stuck. Solution: You can easily move the position of the fuel rod by hand to judge whether it is stuck. If it gets stuck, you need to find a professional to repair it. If there is no jamming, check whether the limit position of the fuel rod is correct.
F, smoke limiter solenoid valve problem (applicable to supercharged engines). Solution: Check whether the solenoid valve is energized. If power is on, replace the solenoid valve. If there is no power, check the circuit problem.
G, nozzle problem. Solution: The injection pressure of the fuel injector is incorrect (check with the fuel injector tester, standard 175+8bar). If the pressure is not enough, use the adjusting gasket to correct the injection pressure. Caution: After the fuel injector is removed, a new O-ring and a new adjusting pad must be used for reinstallation.
H, fuel injection pump problems. Treatment: (1) The injection advance angle is incorrect. Solution: Adjust the fuel supply advance angle. ⑵ If the oil delivery valve is not sealed or the parts are damaged, the treatment method: overhaul the fuel injection pump. ⑶ The oil supply advance device is damaged. Treatment: It may be that the spring is broken, the spring support is worn, and the counterweight is stuck. , so check and replace it.
I, the valve clearance is wrong. Treatment: Check and adjust the valve clearance; Check whether the intake and exhaust valves and valve seats are worn or damaged; Check the wear of piston ring and cylinder liner and the coking or fracture of gas ring; Check or adjust whether the piston top clearance is too large.
2. The engine power is insufficient.
Cause analysis and treatment:
A, lubricating oil level is too high. Treatment: check the oil level and pay attention to analyze the reasons for the high oil level.
B, governor fault and treatment: (1), the engine stop lever is not in the working position, treatment: check the crank adjustment position, check the solenoid valve action, and check the position of the high-speed limit screw. (2) When the refueling rod cannot reach the position of the high-speed speed limit screw, check whether the radial shaft is stuck or whether the position of the speed regulating crank is appropriate.
C, combustion air fault and treatment. (1), dirty air filter. Treatment method: clean the air filter or replace it; (2) The maintenance indicator is damaged. Disposal: Replace the maintenance indicator. (3) The intake and exhaust pipes are not sealed. Treatment: Check whether all sealing rings are complete, whether all flange screws are tightened, whether flange fittings are damaged, and check the alignment of cylinder head and the straightness of exhaust manifold flange when exhaust manifold is not sealed. (4) The supercharger (for supercharged engines) and intercooler are dirty. Treatment method: clean the supercharger.
D, smoke limiter problem. Solution: Replace or adjust the smoke limiter.
E, exhaust back pressure problem. Treatment: (1) The exhaust manifold or muffler is blocked. Solution: Clean the exhaust manifold and muffler and replace the damaged parts. Exhaust brake valve is damaged. Treatment: Overhaul exhaust brake valve.
F, valve clearance problem. Treatment: Check and adjust the valve clearance.
G, fuel system failure and treatment. (1), the ventilation device of the oil tank is blocked. Disposal: Check and clean. (2) There is air in the fuel system. Treatment method: exclude air. (3) The oil circuit is blocked. Solution: Clean the fuel filter element and pipeline. (4) The choke oil return pipe is blocked, and treatment: eliminate the blockage. 5], fuel pre-depression, treatment: check the overflow valve and low-pressure oil pump. [6], the nozzle is broken or the nozzle adjusting pad is not suitable. Solution: Replace the fuel injector and adjusting pad. Once, the problem of check valve of high-pressure pump oil return bolt, solution: replace high-pressure pump oil return bolt. ⑻ Solution to the problem of fuel injection advance angle: adjust the fuel injection advance angle. (9) Problems and solutions of fuel injection advance device: check and replace.
3. The engine temperature is too high (cylinder head alarm temperature 175 degrees, oil alarm temperature: supercharged 125 degrees, non-supercharged 1 15 degrees).
A, cooling system failure. Troubleshooting: (1) The heat sink is dirty. Treatment: Clean the cylinder liner, cylinder head, oil radiator and cold radiator of supercharged engine with compressed air. ⑵ The cooling air deflector is not sealed. Treatment method: check and adjust the position of the pull rod of the deflector, and check whether there are cracks and fragments on the deflector. If yes, replace and adjust. (3) The cover plate at the top of the wind pressure chamber is not sealed. Treatment: check whether the cover plate of the wind pressure chamber is deformed or damaged, and check whether the fastening screws of the cover plate are fastened completely. (4) Whether the cooling fan and fence are dirty, and whether the centrifugal oil filter in the hydraulic coupling in the cooling fan is dirty, treatment: clean the dirt on the cooling fan and fence, and clean the centrifugal oil filter. 5], check whether the exhaust thermostat is damaged, treatment: check and replace the thermostat. [6], check whether the temperature sensor and thermometer failure or damage. Disposal: Check and replace.
B. combustion air problem. (1). The air filter is dirty. Treatment: Clean or replace the air filter. ⑵ The maintenance indicator light is broken. Treatment: Check or replace the maintenance indicator. (3) Treatment: Check whether all sealing rings are complete, whether all flange screws are tightened, whether flange fittings are damaged, and check cylinder head centering and exhaust manifold flange straightness when exhaust manifold is not sealed. (4) The booster intercooler is dirty, and treatment: clean the intercooler. 5. Troubleshooting of supercharger: Clean the compressor cover and impeller of supercharger.
C, exhaust back pressure problem. (1) The exhaust manifold or muffler is blocked. Solution: Clean the exhaust manifold and replace the damaged parts. (2) exhaust brake valve damaged. Treatment: Check the exhaust brake valve and replace the damaged parts.
D, fuel system problems. (1) The choke is broken. Solution: Check the injection pressure or replace the nozzle. ⑵ The oil supply advance angle is incorrect, and the treatment method: adjust the oil supply advance angle. (3) The fuel injection advance device is damaged. Disposal: replacement. (4) The fuel injection pump does not match the engine installation (this problem may occur after replacing the new fuel injection pump). Solution: Recalibrate the pump to correct the oil supply.
E, lubrication system problems. (1) The air deflector is missing or damaged. Solution: Replace and adjust the air deflector. ⑵ Dirty oil radiator, treatment: Clean the oil radiator fins. (3) The oil level is wrong. Treatment: Check whether the oil level is within the standard range. (4) The oil temperature sensor is damaged. Treatment: Replace the oil temperature sensor. 5. The temperature control valve in the oil radiator is damaged. Treatment: The temperature control valve works when the oil temperature reaches 90 degrees. If damaged, please replace it.
4. The engine has no oil pressure or low oil pressure.
First, the oil level and quality of lubricating oil. (1) Operation error, treatment: After starting the machine in a cold state, it must run at a medium speed for a few minutes before accelerating. 2. The oil level is too low. Treatment method: replenish engine oil. ⑶ The viscosity and quality of engine oil are incorrect. Treatment: Fill the engine oil as required.
Assembly and maintenance problems. (1) If the oil is not changed in time, treatment: change the oil at the specified time. ⑵ The oil filter element is dirty. Disposal: Clean or replace the filter element. (3) The oil filter is incorrectly assembled. Treatment: Use metal filter element and pay attention to the correct installation position of the filter element.
C, the oil temperature problem. (1) The oil radiator is dirty. Disposal: Clean the oil radiator. ⑵ The air deflector is missing or damaged. Solution: Replace the air deflector. (3) The temperature control valve in the oil radiator is broken. Solution: Replace the temperature control valve.
D, oil circulation problem. (1) If the oil sensor or pressure gauge is damaged or the wiring is loose, treatment: replace the pressure sensor or pressure gauge. ⑵ The pressure regulating valve is not sealed. Treatment: it needs professional manufacturer's maintenance, and the pressure regulating valve is installed on the main oil passage of crankcase. (3) The connecting pipe of the oil pump is not sealed. Treatment: the connecting pipe (special plastic) between the bypass valve body below the oil radiator and the oil outlet of the oil pump is worn and replaced; The sealing ring at the transition from the main oil gallery accessory bracket to the main oil gallery is damaged and needs to be replaced. (4) The filter screen of the oil pump suction pipe is dirty. Treatment: Check whether the filter screen is blocked and clean it. 5. The oil suction pipe of the oil pump is not sealed. Solution: Check whether there are cracks in the sealing ring and tubing, and tighten the fixing clip. [6]. The check valve of the oil pump is not sealed. Treatment: overhaul by the manufacturer. Once the oil pump is worn, treatment: replace the oil pump.
E. bearing problems. Main bearing and connecting rod bearing wear, treatment: overhaul.
5. The oil consumption is too high.
A, engine load problem. (1) The running-in period of the new engine is normal (the fuel consumption is not more than 1.5%). ⑵ The engine is in a low load state for a long time. Solution: Avoid idling the engine for a long time.
B, oil level and oil quality problems. (1) The oil level is too high. Treatment: reduce the oil level and observe the reasons for the increase. ⑵ The viscosity and quality of engine oil are incorrect. Treatment: Add engine oil as required.
C. oil leakage. (1), crankshaft breather is damaged, treatment: check the crankcase pressure and clean the breather valve. ⑵ Wear of valve guide, treatment: repair cylinder head. Overhaul. (3), (4), piston, piston ring and cylinder liner are worn, and treatment: overhaul.
D, exhaust gas turbocharger is not sealed. Treatment: the labyrinth oil seal used at the joint between the bearing box of exhaust gas turbocharger and the shaft of turbine and compressor is damaged, or the section of the oil return pipe of turbocharger is shrunk due to external collision.
E. air filtration. For engines with oil bath air filters, check whether there is too much oil in the filter oil pool. Treatment: found excess oil.
F. operational issues. The engine works rudely due to frequent throttle or overload, which leads to poor combustion, carbon deposition and piston ring jamming. Treatment: standardize the operation of lifting the throttle.
6. The engine emits blue smoke (like the problem of high fuel consumption, I won't go into details).
A, engine load problem.
B, the oil level is too high.
C. internal problems of the engine.
D, exhaust gas turbocharger problem.
E. air filtration.
7. White smoke from the engine
A, cold start problem. (1), the engine does not enter the working temperature, which is a normal phenomenon and should not be handled. ⑵ Failure of the flame glow plug or solenoid valve, treatment: Check the oil supply of the glow plug, and replace it if there is none. (3) If the preheating device fails, treatment: check the preheating device line step by step or replace the damaged parts.
B, fuel system problems. (1), water in the oil tank, treatment: remove the water in the oil tank, and check the cause of water in the oil tank. ⑵ If the nozzle is damaged or the nozzle adjusting pad is wrong, treatment: check or replace the nozzle and adjust the thickness of the pad. (3) Incorrect fuel supply advance angle. Solution: Adjust the oil supply advance angle and check the oil supply advance device. (4) The flameout at idle speed indicates that the damage of fuel injection pump parts is aggravated and the pump needs to be recalibrated.
C, engine itself. ⑴ Valve clearance is wrong, and treatment: Check and adjust the valve clearance. ⑵ If the compression pressure is too low, treatment: check the wear of intake and exhaust valves and valve seat rings, check the wear of piston rings and cylinder liners and treat them.
Smoke limiter solenoid valve problem. For supercharged engines, it is necessary to check the solenoid valve of the smoke limiter.
8. The engine emits black smoke
A, combustion air problem. (1) The air filter is dirty, and the treatment method: clean the air filter. ⑵ If the maintenance indicator is damaged, treatment: replace it. ⑶ The intercooler is dirty, and treatment: clean the cooling fin of the intercooler. (4) The intake and exhaust pipes are not sealed. Treatment: Check the state of the sealing ring, check the fastening of the flange screws, check the alignment of the cylinder head and the straightness of the exhaust pipe. 5] The supercharger is dirty. Disposal: Clean the supercharger.
B, exhaust back pressure problem. (1) The exhaust manifold or muffler is blocked. Solution: Clean the exhaust manifold or muffler and replace the damaged parts. (2) exhaust brake valve damaged. Treatment: Check and replace the damaged parts in exhaust brake valve.
C, fuel system problems. (1) The electromagnetic valve of the flame preheating device is not sealed. Solution: When the engine is running, loosen the threaded pipe on the flame heating plug joint for several turns. If there is fuel in the loose threaded pipe, it means that the solenoid valve is not well sealed and needs to be replaced (note: if the solenoid valve is not well sealed, the fuel will enter the engine intake pipe through the flame heating plug, which may lead to serious engine accidents due to excessive temperature). ⑵ If the nozzle is damaged, the treatment method: adjust the pressure or replace the nozzle. ⑶ The fuel supply advance angle is incorrect, and treatment: adjust the fuel supply advance angle. (4) The fuel injection advance device is damaged. Solution: Replace the fuel injection advance device. 5. The fuel return pipe of the fuel injector is blocked, and treatment: eliminate the blockage.
D, engine problems. ⑴ The valve clearance is wrong, and treatment: adjust the valve clearance. ⑵ If the compression pressure is too low, treatment: check the wear of intake and exhaust valves and valve seat rings, check the wear of piston rings and cylinder liners and treat them.
E, smoke limiter problem. The smoke limiter opens the stroke of the speed regulating toothed bar prematurely. Treatment: It needs to be adjusted on the high-pressure pump test bench.
9. Other abnormal conditions of the engine.
A, working speed is too low under full load. (1). The position of the engine parking lever is incorrect. Solution: Adjust the parking lever to the working position. ⑵ The refueling rod cannot reach the position of the high-speed limit screw. Treatment: Adjust the pull rod to make the radial shaft rotate flexibly. (3) Improper speed adjustment, treatment: (by professionals), unload the engine to make the engine enter the highest idle speed. If the ratio of the highest idle speed to the rated speed is about 5%~ 10%, it means that the governor is adjusted correctly, otherwise the fuel quantity of the fuel injection pump will be adjusted. (4) The engine is overloaded. Handling: Check the load. 5], according to the engine power shortage (article 2) for inspection.
B, the engine speed drops too fast. (1), the oil tank exhaust device is blocked. Solution: Remove the fuel tank cover and check whether the fault disappears. If yes, clean the fuel tank exhaust. 2, fuel filter or tubing blockage, treatment, cleaning and exhaust.
C, engine speed fluctuation. (1) Improper idle speed adjustment, treatment: loosen the idle spring to make the engine enter the maximum idle speed, adjust and tighten the idle spring to increase the maximum idle speed by 5~ 10 rpm, tighten the lock nut and screw on the spline nut. ⑵ If the air in the fuel is not exhausted, treatment: exhaust the air in the fuel. (3) Serious oil leakage or partial oil injection from the nozzle. Solution: Replace the faulty nozzle. (4) Idle flameout, treatment: After the above problems are eliminated, it is judged that the wear of fuel injection pump parts is increased and the pump needs to be recalibrated. 5]. The governor parts are worn or the speed regulating toothed bar is not flexible. Solution: Calibrate the pump or regulator.
D engine vibration or abnormal noise. (1) The engine suspension is loose. Handling: Check the fastening of accessories connected to the engine and re-fasten them. ⑵ The rubber shock absorber installed on the engine crankshaft is damaged. Solution: Replace the rubber shock absorber on the crankshaft. (3) The coupling at the output end of the engine is seriously worn, resulting in different power output shafts during operation. Solution: Replace the output coupling and adjust it in place. (4) The engine bearing bush is damaged and the box body is deformed. Treatment: engine disassembly and maintenance. 5. The rubber shock absorber at each joint of the engine is aged and deformed. Treatment: Replace and adjust the aging and deformed rubber shock absorber and bolts.