Diagnosis and Maintenance of Strange Sound Fault of Diesel Engine of Diesel Forklift with Side Shift
1. There is a knocking sound
Fault phenomenon: Generally, for diesel engines without fuel supply advance device, in order to obtain the best advance angle at the rated speed, the fuel supply appears to be too early at low speed, resulting in a uniform "click" knocking sound, which is normal . After the fuel supply time is delayed, the knocking sound is reduced or disappeared, but the power is also reduced accordingly. cause of issue:
1. The oil supply time is too early;
2. The injector drips oil, and the oil outlet valve is worn or stuck;
3. The oil supply volume of each cylinder is uneven.
Diagnosis and exclusion methods:
1. When the oil outlet valve is stuck, remove the high-pressure oil pipe and pump oil with the hand oil pump, diesel oil will come out from the oil outlet valve joint;
2. When the fuel injector is stuck and the diesel engine is running, remove the high-pressure oil pipe joint at the fuel injector end, and the high-pressure gas will be ejected from the fuel injector during the compression stroke;
3. When a certain cylinder has knocking sound, it can be checked by cutting off the oil. When the high-pressure oil pipe of a certain cylinder is loosened, the knocking disappears, which means that the cylinder and the fuel injector of the cylinder are faulty. When the fuel injector of this cylinder is exchanged with the fuel injector of another cylinder, if the fault is transferred to another cylinder, it means that the fuel injector is faulty and should be removed for inspection and adjustment.
2. "Traveling Car"
Fault phenomenon: The speed of the diesel engine is unstable when it is working. There are two situations: one is that the speed fluctuates greatly, and the sound is loud and small, which can be clearly distinguished; the other is that the speed fluctuates within a small range, and the sound is not easy to distinguish clearly. And irregular, when it may occur at any speed or under any load conditions, it often causes the engine to stall.
cause of issue:
1. There is poor contact between the fuel supply rack of the fuel injection pump and the moving gap of the plunger, or there are foreign objects. When the fuel supply rack moves with a strong negative force, the sensitivity of the governor decreases, resulting in "swimming";
2. Partial air leakage of the vacuum speed controller;
3. Improper adjustment of the speed governor, failure of the speed regulating spring, and wear of the joints of each rod system. The gap increases, so that the governor does not adjust the speed in time, and the engine speed fluctuates.
Diagnosis and exclusion methods:
1. Readjust the fuel supply of each cylinder;
2. Clean, grind or replace the injector;
3. Repair or replace the gear rod connecting pin;
4. Adjust the axial clearance of the camshaft to the specified value;
5. Replace the plunger spring or oil outlet valve spring;
6. Replace the bushing and flying iron pin;
7. Readjust and assemble the adjusting rack and adjusting gear;
8. Repair or reassemble the adjustment gear rod or throttle lever;
9. Use the hand oil pump to remove the air;
10. Readjust the low speed stabilizer or low speed limit screw.
3. "Flying Car"
Fault phenomenon: The speed of the diesel engine is out of control, and the speed exceeds the maximum allowable speed. When "speeding", if measures are not taken in time, the diesel engine may be damaged.
cause of issue:
1. The vacuum hose of the vacuum speed controller is inserted incorrectly;
2. Improper adjustment of the governor, or failure of the governor;
3. The gear rod of the fuel injection pump is not flexible and is stuck at the maximum fuel supply position.
Diagnosis and exclusion methods:
1. Unplug the hoses of the vacuum chamber and atmospheric chamber of the vacuum speed controller;
2. Remove the air filter, block the intake pipe, and prevent air from being sucked into the cylinder;
3. Pull the oil supply gear lever of the fuel injection pump to the flame-off position, so that the fuel injection pump stops fuel supply;
4. Check and open the joint of the high-pressure oil pipe or the low-pressure oil pipe of the fuel injection pump, and cut off the oil circuit;
5. Put in the high gear, step on the brake pedal, and force the diesel engine to stop. To reassemble the adjuster rod or throttle lever connection, replace the governor spring.