Forklift common general fault maintenance information
Jul 07 , 2022
Forklift truck common general fault maintenance information

The first starter can drive the engine to run, but there is no sign of starting.
This phenomenon caused by the engine is generally caused by the poor fuel system. It is divided into low-pressure oil circuit and high-pressure oil circuit. When checking, it is necessary to determine which part of the fault comes from. First, deflate the fuel injection pump, loosen the bolt and turn the hand fuel pump to see the oil. If there is no oil or bubble-like diesel flows out, it means that it is a low-pressure oil circuit, otherwise it is a high-pressure oil circuit failure.
(1) Failure of the low-pressure oil circuit
1. There is no oil in the fuel tank: the treatment method is refueling;
⒉The oil pipe is blocked, the treatment method: clean and dredge;
3. The oil pump filter is blocked, the treatment method: clean up;
4. The oil pipe is aging and leaking, replace it;
5. Diesel filter is too dirty, replace it;
6. The piston of the oil pump is damaged, replace it;
(2) High pressure oil circuit failure:
1. The fuel injection pump does not work, correct it
⒉. The injector does not work, correct or replace;
The second phenomenon of premature injection time
1. There is a rhythmic and crisp "quack" metal percussion sound in the cylinder;
2. The engine is overheated, weak, and emits black smoke;
3. Poor idle speed;
4. Not easy to start; handling method
Loosen the fixing screws of the fixing plate, and slowly delay the fuel injection time until the fuel injection situation improves. You can also remove the high pressure pipe of the first cylinder and turn the crankshaft. Pay attention to the oil level in the pressure seat of the oil outlet valve on the fuel injection pump. At the moment when the oil level just fluctuates slightly, check whether the advance angle meets the requirements from whether the fuel injection timing scale line on the flywheel and the mark on the flywheel shell coincide, and if it does not meet the requirements, adjust it again.
The third injection time is too late
1. The cylinder produces a low and indistinct percussion sound.
2. The engine speed cannot be increased with the increase of the accelerator;
3. Engine overheating: powerlessness, white smoke;
Check whether the fixing screw of the connecting plate is loose or displaced, you can loosen the fixing screw of the fixing plate, and slowly advance the fuel injection time until the fuel injection situation improves. If the adjustment is invalid, check the timing adjustment on the plunger tappet of the fuel injection pump Whether the screw is out of balance, if it is out of balance, readjust it.
The fourth reason for engine failure
1. Insufficient oil supply in the low-pressure oil circuit, blocked vent holes in the fuel tank, blocked oil pipes, loose joints and loose gaskets. Treatment method: find out the fault, clear the oil circuit, and replace it;
2. The air filter is blocked and the air intake is not smooth, the treatment method is to replace or clean the filter;
3. Diesel filter is blocked, treatment method: replace;
4. The oil supply of the oil pump is insufficient, the treatment method: repair or replace;
5. There is air or moisture in the fuel system, treatment method: remove the air or moisture;
6. The injection time is too early or too late, the treatment method: adjust;
7. The exhaust pipe or muffler is blocked and the exhaust is not smooth, treatment method: clean;
8. The fuel injection volume of the fuel injection pump is insufficient, the treatment method: correct the fuel pump;
9. Poor atomization of individual injectors, treatment method: find out where the cylinder failure is to replace or repair the injector;
10. The engine temperature is too high, check the cooling system to find out the fault and eliminate it;
11. Improper adjustment of the throttle cable, adjust;
12. Mechanical factors cause the cylinder pressure to be too low. The mechanical factors include: the valve of the valve train is not closed tightly and the piston, piston ring and cylinder liner are seriously worn, etc., adjust the valve clearance, re-grind the valve or replace the piston, piston ring and lining, grinding the cylinder liner, etc.;
Fifth, the engine suddenly turned off during operation
1. The engine suddenly stalls during operation;
⒉. No abnormal symptoms before extinguishing;
Fault causes and solutions:
1. No oil in the fuel tank: treatment method: refuel;
2. Diesel fuel is mixed with water or air, treatment method: exclude water or air;
3. The oil pipe is blocked or ruptured, the treatment method: dredge or replace the oil pipe;
4. The fuel filter is blocked, the treatment method: replace;
5. The oil pipe joint is loose and the air intake is dealt with: squeeze the joint to drain the air in the oil circuit;
6. The oil pump does not supply oil, the treatment method: repair or replace the oil pump;
Transmission system part
The first hydraulic transmission technical parameters
1. Transmission power 40KW;
⒉. Input speed 1800-2400N/min;
3. Turn (viewed from the input end) clockwise;
4. Clutch piston stroke, 1.2-1.7MM;
5. Working oil, 20# turbine oil (or 6# or 8# hydraulic transmission oil)
6. The working oil temperature is 70-95 degrees Celsius;
7. The maximum oil temperature, not more than 110 degrees Celsius;
Second drop in efficiency
(1) Torque converter part
1. The engine speed drops, the treatment method: increase the engine speed
⒉. There are air bubbles in the oil, check the tightness of the pipeline and whether the hydraulic oil is deteriorated
3. The oil temperature rise is too high or too low
(2) Transmission part
1. If the abrasive sheet is stuck or worn, check whether the abrasive sheet has glue, uneven contact, and warpage.
2. Grind the sealing ring or O-ring, check whether the sealing ring and groove width are worn or damaged (3) The oil temperature is too high
(1) Torque converter part
1. The torque converter works in the low speed ratio area for a long time, the efficiency of the torque converter is very low, or the time in the stall state is too long, this working condition should be changed and the above working conditions should be avoided.
2. When the speed ratio is high, the one-way clutch is stuck and out of control, which should be checked and eliminated.
3. If the amount of oil is too small, or bubbles are generated in the system, increase the amount of oil to adjust the pressure of the exhaust valve. 4. If the quality of the oil is not up to standard, it should be replaced with new oil.
(2) Transmission part.
1. The clutch is blocked, check whether the friction plate slips.
2. If the bearing is damaged, check whether the mating surface is damaged.
(3) The gearbox does not work
1. Check whether the control valve has spring stuck and broken.
2. Check whether the main oil pressure is normal, if not, check whether the triple pump is too worn or damaged.
3. If the main oil pressure is normal, check the clutch oil pressure. If it is abnormal, check whether the sealing ring or O-ring is worn or damaged. Check whether the clutch and clutch piston ring are damaged.
4. Check whether the torque converter oil pressure is normal. If not, check the torque converter.
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