dingbo@dieselgeneratortech.com
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Oct. 23, 2021
Dingbo power is very pleased to share and discuss the diagnosis methods of diesel engine fuel injector with you. In the previous articles, we discussed some fault analysis and maintenance methods of fuel system. Today, we will talk about the diagnosis methods of diesel engine fuel injector.
The diagnostic methods for diesel engine injector problems are as follows: over time, the injector will become tired and weak. Even if they are electronic, sometimes the mechanical parts in the injector may wear out, stop working normally, or even fail.
In this case, the scan tool will usually find the cylinder that contributes to the problem.
However, in addition to wear or fatigue, fuel injectors may fail. One of the most common faults is fuel injector body rupture. When cracking, it will cause other problems, which is more difficult to determine. Although the injector body may break, the engine may still run well and only take a long time to start.
In addition, an increase in the oil level may be noticed, noting some fuel dilution in the oil. When the engine is shut down, cracks in the injector body usually cause fuel to drain back to the tank from the fuel line and rail. When a leak occurs, the engine must be over rotated for a period of time in order to recharge the injection system.
The normal starting time of the common rail injection system is usually about three to five seconds. This is the time required for the common rail pump to establish the fuel pressure to the threshold. In the engine, the controller does not activate the fuel injectors until the fuel rail pressure reaches the threshold. When the fuel injector breaks and the fuel leaks downward in the injection system, the starting time will almost double in order to refill the fuel system and reach the threshold required for ignition.
Determining exactly which injector is broken can be a long process. First remove the valve cover, and then turn the engine to idle. Study the injector body of each cylinder with a lamp. Sometimes, if the outside of the injector body is cracked, you may notice a small wisp of smoke from the injector. The wisp of smoke that can sometimes be seen is actually the atomization of fuel released from the crack. But this wisp should not be confused with channeling gas, which can also be seen. If the outside of the fuel injector breaks and produces a wisp of smoke, you can smell diesel in the air.
Although today's diagnostic tools and advanced engine electronics make it easier to identify the performance problems of diesel engines, this does not mean that all problems can be solved so easily. For more details, please contact Dingbo power.
What are the abnormal phenomena when the fuel injector of diesel generator set fails?
1) Black smoke from exhaust;
2) Abnormal vibration occurs in the power part of each cylinder;
3) Power drop.
In order to find out the faulty fuel injector, check it according to the following methods: first run the generator at low speed, then stop the fuel injection of the fuel injector of each cylinder in turn, and pay attention to the changes in the working conditions of the diesel engine. When the fuel injector of a cylinder is stopped, if the exhaust no longer emits black smoke, and the diesel engine speed changes little or does not change, it indicates that the fuel injector of the cylinder is faulty; If the diesel engine becomes unstable, the speed drops significantly, or even stalls, the cylinder injector works normally.
Test and check the fuel injector corrector. If the following conditions occur, the fuel injector is faulty.
1) The injection pressure is lower than the specified value.
2) The fuel injection does not atomize, forming an obvious continuous oil flow.
3) For multi hole injector, the oil beam of each hole is uneven and the length is different.
4) The fuel injector drips.
5) The spray hole is blocked and does not give oil or the spray is dendritic.
Dingbo Power suggest to repair and replace the fuel injector if the above problems are found.
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