Poor diesel quality leads to slow excavator operation

A certain customer has oneHitachi EX200-5The excavator moves slowly and weakly, but the engine has no black smoke

Processing procedure:　

1. It was found that the filter element and diesel were dirty. After replacing the filter element, the problem was not solved. It is suspected that the diesel road has been damaged by dirty diesel
2. When making the engine performance curve, it was found that the engine had a load drop, especially at low speeds where the peak suction pressure was only 170KPa (reference data of about 200KPa), the common rail pressure was normal at 133MPa, and the indicated injection quantity was 130 (reference data of 117)
2. Maintenance process
Due to accessory issues, we replaced the SCV valve first, but the cylinder repair situation did not change
Later, all fuel injectors were replaced/ECU QR codes were rewritten, and the machine returned to normal
3. Analysis
1. Low suction pressure may be caused by low fuel injection after the injector is damaged, resulting in low exhaust gas volume and low turbocharger speed
2. After the injector is damaged, the success rate decreases due to low fuel injection volume and engine deceleration
3. When the engine power decreases, the ECU instructs the SCV valve to increase the fuel supply. However, due to damaged injectors, the purpose of increasing engine power cannot be achieved
4. If the common rail is normal, it proves that the fuel supply pump/common rail is normal. If the injector is damaged, the fuel injection quantity will decrease, so the engine does not emit black smoke, which is exactly the opposite of our Type 6 car where the injector is damaged and emits black smoke
5. It is worth noting that the engine cylinder compensation curve shows that all four cylinders are normal, with 1.2.4 being zero, and only three cylinders being 0.3, but all are normal. (Cylinder compensation value:+-4.5, allowable value+-8). Therefore, it cannot prove that the fuel injector is not damaged
4. Solution
Enable customers to use diesel fuel effectively