Construction machinery diesel engine fuel pump failure in 3 cases

Fuel injection pump is an important part of the diesel fuel system, the quality of its work directly affects the diesel engine power, economy and reliability. In the repair of individual repairman pay less attention to the fuel pump, resulting in some man-made faults. Here are just three cases for troubleshooting reference. (1) A 6135K-9a diesel engine used in a ZL50CII loader has no obvious fault during idling operation, but when it accelerates, the sound of "sudden protrusion" appears and the color of exhaust smoke is white or black and unstable. , The beginning, that injection timing is wrong, but the fuel injection timing after readjustment, the fault still; check the low and high pressure oil, were found no problem. Finally, when removing the fuel pump, it was found that the lock nut at the tip of the fuel injector was loose and the keyway of the fuel injector and the camshaft of the fuel injection pump had been widened due to wear. The thickness of the semicircular key was less than half . Milling key again, installed after the failure disappears. It is understood that the machine's fuel pump has just been repaired not long ago, resulting in the failure of the direct cause is: Maintenance personnel installed in the extension of the fuel injector did not tighten the lock nut torque, so that the engine speed when the operation Due to the fuel injector ahead of the camshaft with loose Kuang and aggravated the keyway and the semicircle key wear and tear, resulting in fuel injection instability. (2) A 6135K-12C diesel engine used for the loading of a TL180 bulldozer with a BH6B100YS490 fuel injection pump. In an engine overhaul, the fuel injection pump and injector are on the test bench were calibrated. The engine after running in, the bulldozers into the earthwork, then because of the engine work unable to work, and in the engine idling throttle, I feel bad acceleration. After examination, the engine, fuel injection timing are normal, oil-free place, governor, fuel injection pump, low pressure and high pressure oil are also no problem, it is suspected that the school pump may be rated working condition fuel Tune too low due. As a result, the fuel pump removed and re-corrected on the test bench, it turned out to be the school pump master mistakenly fuel pump rated operating conditions reduced by 6mL / 200 times. Re-set the fuel pump back, test machine, the operation normal and powerful. (3) A W4-60C excavator fitted with a F6L912 diesel engine suddenly goes out on its way to the worksite, but after many starts it fails to start. Observe the exhaust situation, but no smoke, initially concluded that the oil fault. Check, pump oil with a manual pump, the result is a good oil, the oil no leakage, clogging; swing speed handle, the fuel pump lever adjustment rod did not respond. When disassembled the governor, it was found that the connection between the oil supply lever and the governor lever was loosened and the pin was broken. Reconnect the fuel rod and governor lever, and lock with the new pin, start quickly when activated, indicating that the fault was ruled out. The reason for this failure is that the maintenance personnel did not replace the new pin as required while assembling the governor and still used the new unused and cracked pin to break the pin. The oil supply rod and the speed control lever Connection loose, resulting in failure to start.

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