The excavator emits black smoke, which can damage some of the owners. It is conceivable that the construction progress will be affected if there are large and small failures of the excavator. Among them, the problem of black smoke from the excavator is a 'troublesome fault' that we don't want to encounter 100%. Today, let's share with you the diagnosis of black smoke maintenance of the excavator engine, hoping to help you.
Diagnosis steps for excavator engine running unevenly and emitting black smoke:
1 First, check the working condition of the engine. You can try to conduct cylinder by cylinder fuel cut-off test when the engine is running. When a cylinder is fuel cut-off, if the engine speed is significantly reduced, black smoke is reduced, and the knocking sound becomes weak or disappears, it means that the fuel supply of the cylinder is too much; If there is no change or little change in the engine, it means that the fuel supply of the cylinder is too small; If the engine speed changes little and black smoke disappears, it indicates that the cylinder injector spray quality is poor. After finding out the faulty single cylinder, further check the cause of the fault, such as the condition of the cylinder injection pump plunger pair, whether the sector gear fixing screw is loose, and whether the plunger spring is broken. If it is normal, the injector can be disassembled for inspection, and if necessary, a new injector can be installed for comparison; If the fault disappears when a new injector is used, the original injector is faulty.
2. If the fuel injection volume of each cylinder is too large, open the governor cover and check whether the scale of the adjusting gear rod moves too much towards the fuel injection pump housing. If the diesel engine emits black smoke, you can hear a crisp knocking sound in the cylinder, which indicates that the fuel injection time is too early, and the fuel injection timing should be calibrated correctly. If the air filter is blocked (the filter element is dirty) during the inspection, it should be cleaned and blown immediately.
3 Secondly, if the plunger tappet of the fuel injection pump is equipped with adjusting screws, check whether the fuel injection timing of each cylinder is consistent.
4 If there is no problem with the above items, the single cylinder with fault can be pressure tested to determine whether the fault is caused by wear and leakage of cylinder, piston, piston ring, etc. or poor valve sealing.
The above briefly summarizes several diagnoses of the excavator emitting black smoke, and finally reminds all operators that when the excavator emitting black smoke is found, in order to ensure the normal use of the excavator, users need to promptly notify professional after-sales service engineers to troubleshoot and repair.
