In the beginning of 1985, a batch of RD030 dump trucks were purchased. The engine was a Cummins NTA-855C-C310 inline 6-cylinder turbo-supercharged diesel engine with power: 234KW/2100r/min. During the construction, the batch of vehicles fully utilized its advantages of large power, strong bearing capacity, convenient operation, and other unmatched features of other heavy vehicles. However, in the process of repairing the car's engine, we discovered that some of the faults are universal, and two cases have been taken.
1. The engine emits white smoke: After an engine is overhauled, it enters the tunnel to pull slag. During the process of loading slag, it turns off (but does not turn off the power supply) and restarts. The muffler emits a white smoke. The construction personnel cannot work. After analysis, it is considered that the fuel enters the combustion chamber, resulting in incomplete combustion of the fuel. However, which one of the cylinders cannot be determined. Check the dipstick, the oil plane is higher than the original scale; disassemble the exhaust pipe, observe the exhaust ports of each cylinder, test several times, the results are different, it is still not sure which cylinder into the fuel, replace each cylinder injection seal gasket one by one. The situation remains the same.
As shown in the drawing of the PT fuel injection system, the position of the fuel tank can be seen from the figure. Therefore, when the engine is stopped, the fuel cannot flow to the fuel injector by itself, so a PT pump is set to the fuel injector. Oil check valve. When the engine is off but the power is not turned off, the PT pump solenoid valve is open. Under normal circumstances, the fuel passing through the electric check valve in the oil passage is under the action of the spring force of the one-way valve under the action of the check valve's spring force. The fuel is not entered into the cylinder by the sealing machine; if the check valve spring force is weakened, the fuel depends on the fuel tank. When the high pressure difference between the PT pump and the PT pump is greater than the spring force, the fuel flows through the check valve to the injector .
1.PT Pump 2. Fuel Filter 3. Fuel Tank 4. Return Line 5. Fuel Injector 6. Fuel Distribution Line 7. Solenoid Valve 8. Inlet Check Valve 9. Return Check Valve Replacement Fuel Entry To the valve, the above fault is eliminated immediately. This failure has occurred in most engines.
2, PT pump AFC cover flow valve leakage diesel phenomenon: When the engine starts, there is always a fuel drip from the AFC cover flow valve, generally due to the AFC diaphragm wrinkle surface damage, making the PT pump fuel leakage APC diaphragm cavity caused leakage. As long as the AFC diaphragm is replaced, this fault can be eliminated.
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