bulldozers are weak in bulldozing, work efficiency is low, diesel engine power is insufficient, and exhaust gas is accompanied by black smoke. When the load is increased, black smoke is particularly high. This is a common bulldozer engine failure. I believe most operators have encountered it. Then, how do we check and eliminate such failures?

1: Troubleshoot the cause of the fault

Diesel engine water temperature, oil temperature, intake air temperature and pressure (including sensor failure) are abnormal. After the metering unit, rail pressure sensor, fuel line, and injector fail, the diesel electronic control unit detects the failure and will not stop immediately. Instead, the power of the diesel engine is limited, so that the speed of the diesel engine can only be increased to 1 500r/min. When using a bulldozer, it will feel insufficient power.

When there is insufficient power, first check whether the instrument has a fault code display, and then find the fault location according to the fault code to eliminate the fault.

The instrument has no fault code display, and most of the mechanical parts are faulty. For example, a bulldozer user reports that he has been changing the fuel and oil filter elements in accordance with the diesel engine maintenance regulations for 250 hours, and regularly cleaning the air filter. After the second 250h maintenance, there was insufficient power and no fault code. This ruled out the electrical control system failure and judged it as a mechanical failure. The inspection found that there was oil contamination at the connection between the exhaust manifold of the third cylinder of the diesel engine and the cylinder head.

2: Troubleshooting method

Disassemble the exhaust manifold and find that there is oil in the exhaust duct. Remove the injector and send it to a professional maintenance station for testing on special equipment. After testing, it is found that the injector needle valve is stuck and cannot work. From this analysis, the oil in the exhaust duct is caused by the inoperative fuel injector of this cylinder, which causes the volatile oil to condense and leak here.

After installation and maintenance of the fuel injector, start the diesel engine, the diesel engine starts normally, the smoke color is normal, there is no black smoke when working under heavy load, the performance of the whole machine is restored, and the power shortage fault is eliminated.