What is the reason for the insufficient power of the diesel engine? How to solve it?
1.Faulty injector
Injector faults are generally divided into mechanical faults and wiring faults.
Mechanical failure (stuck needle valve): due to a large amount of dirt or water corrosion in the diesel fuel, the needle valve is stuck in the fuel injector and cannot work. Note: ECU may not report errors.
Wiring fault: due to vibration, wear and other reasons, the harness is disconnected or directly connected to the cylinder head and short-circuited to the ground. The ECU will report an error.
The judgment method is as follows:
The idle speed is unstable, and the sound of the diesel engine is abnormal.
Use the cylinder breaking method or the high pressure oil pipe tactile method to judge (the diagnostic tool is used for acceleration test judgment).
The fault diagnosis instrument generally has the function of excitation test for fuel injector.
2.Coolant temperature, oil temperature, intake air temperature too high
When the coolant temperature, oil temperature and intake air temperature are too high, the ECU will enter the overheat protection mode to limit the engine power.
Reasons and solutions for high coolant temperature:
The radiator water level is too low. Check for water leakage and add water.
The radiator is blocked. Check the radiator, clean or repair it.
The water pump belt is loose. Adjust the tension as required.
The water pump gasket is damaged and the water pump impeller is worn. Check and repair or replace.
Thermostat failure. Replace.
The water pipe seal is damaged and leaks air. Check water pipes, joints, gaskets, etc., and replace damaged parts.
Reasons and solutions for high oil temperature:
The oil level of the oil pan is low or lack of oil. Check the oil level and oil leakage, repair and add oil.
The oil temperature is high. Check and eliminate the above causes of high oil temperature.
The oil cooler does not flow smoothly. Check and clean.
Reasons and solutions for high intake air temperature: check the cooling capacity of the intercooler.
3.Fuel metering unit fault
The fuel metering device is an actuator that controls the fuel rail pressure and is installed on the high-pressure fuel pump. After the metering device fails, the high-pressure oil pump delivers fuel to the fuel rail at the maximum fuel supply. At this time, the pressure relief valve on the common rail pipe will normally open and the diesel engine will make a "click" sound. If the rail pressure sensor is faulty, a similar phenomenon may occur.
In this case, check the circuit to determine whether the fuel metering unit or the fuel rail pressure sensor is faulty.
4.Abnormal fluctuation of rail pressure caused by fuel pipeline leakage
The engine output is insufficient. During vehicle operation, the vehicle speed will be unstable and the vehicle will move forward and backward. At this time, check the sealing of the fuel line and repair the leaking part.
5.Sensor failure
The intake pressure sensor is the sensor used by the ECU to estimate the intake volume (installed on the intake pipe), the coolant temperature sensor is the sensor used to judge the thermal load of the engine (installed on the exhaust pipe), and the common rail pressure sensor is the sensor used to detect the fuel pressure of the common rail pipe (installed on the common rail pipe).
Check the intake pressure sensor, coolant temperature sensor and fuel rail pressure sensor for normal operation. Use a scan tool to check its output data flow to determine whether it works properly. Replace the faulty sensor in time. If the fuel rail pressure sensor does not work properly, replace it with a common rail pipe.
6.Check the operation of turbocharger
Check whether there is noise, oil leakage, air leakage and intercooler heat dissipation during operation. Special attention should be paid to the very high speed of the supercharger compressor. If the lubrication is not in place, it is very likely to be damaged. When the vehicle stops, the engine shall not be stopped immediately. Before the engine stops, reduce the engine temperature and the speed of the supercharger to protect the supercharger.
