Cause analysis and diagnosis method of Kobelco excavator engine failed to start
Article theme: the cause of "the Kobelco excavator engine cannot start", and the diagnosis method of the fault is introduced in detail (the engine speed / timing diagnosis method, the fuel system diagnosis method and how to diagnose and eliminate the excavator engine can't start the fault when the display panel indicates the fault code).
The reason why Kobelco excavator engine failed to start:
There is a loss of electricity in the battery.
The battery cable is not well connected.
(3) there are some malfunction codes or event trouble codes that make the diesel engine unable to start.
ECM no power supply.
The oil level is too low.
The electromagnetic coil of the starting circuit or the starting machine has trouble.
The boot machine is damaged.
The gear ring of the flywheel is overworn.
There is a failure in the intake heater of the starting auxiliary device.
The stop switch of the diesel engine is in the ON position.
The speed / timing sensor is faulty, incorrect installation and needs calibration.
The pressure of the fuel injection is not normal.
The injector does not work.
There is a failure in the fuel supply system.
There is a burning failure.
The internal parts of the diesel engine are bent and stuck.
Test method of speed / timing for Kobelco excavator engine:
(1) shake the diesel engine to observe the diesel engine speed on the ET screen. If ET shows Or/mim, then check the speed / timing sensor. When the initial shake, it may show the diesel engine speed signal abnormal. Once the ECM can calculate the diesel engine speed according to the signal, this information will be replaced by the diesel engine speed.
Check the calibration of diesel engine speed / timing sensor.
3. Confirm the correct installation of the reference gear. If the gear is reversed, the diesel engine cannot start. Check whether the positioning between the crankshaft and the camshaft drive gear is correct. If necessary, fix the positioning and / or replace the drive gear.
Kobelco excavator fuel injection pressure inspection method:
Check the oil level.
If the diesel engine is repaired in the near future, then there may be air in the fuel injection pressure loop. Let the diesel engine warm up and operate the diesel engine to discharge the air in the injection driven pressure loop.
(3) comparing the actual driving pressure and the required driving pressure on the ET, if the difference between the two readings is not more than 2MPa during the period of the failure, it does not show that the problem is not in the fuel injection pressure loop.
Check the sealing condition of the injection drive pressure control valve. If there is a sealing failure, replace the seal and repeat steps 3.
Check whether wiring harness connected to fuel injection drive pressure control valve is open and / or short circuited.
Measuring the coil resistance of the injection control pressure control valve should be 4~16 ohm; otherwise, the fuel injection pressure control valve should be replaced.
Use ET to perform fuel injection pressure overload test. If the injection drive pressure is low, the high pressure oil circuit may leak.
A. remove the plug of the fuel injection actuating pressure control valve and the injector connector.
B. stop the fuel injector by ET or diesel engine shutdown switch.
C. remove the cover of the valve mechanism.
D. check whether the nozzle of the injector connector and the cross cylinder seal are leaking and turn the diesel engine.
E. excludes leakage faults and repeats step D.
F. if the fuel injection pressure is still low during the rocking period, the fuel injection pressure control valve may be malfunction, replacing the fuel injection pressure control valve and repeating the steps.
Test method for the fuel system of Kobelco excavator:
Check the fuel oil level by visual inspection. Do not rely only on the fuel gauge. Add fuel if necessary. If the diesel fuel is used up, the air must be discharged from the fuel system.
Check whether the fuel pipe has throttling, collapsing and clamped pipelines. If the fuel pipe is faulty, repair or replace it.
Check whether there are foreign bodies in the tank, and foreign matter will hinder fuel supply.
(4) after replacing the fuel filter, repairing the low pressure fuel oil supply loop, or replacing the injector, check the air in the low pressure fuel supply system. Use the observation window in the low pressure oil supply pipeline to judge whether there is air in the fuel oil. 2min.
The air is discharged from the low pressure fuel supply circuit.
Check the fuel quality. If the temperature is below 0 C, check if there is solidified fuel (wax).
When the diesel engine is rocking, check the fuel pressure behind the fuel filter. If the fuel pressure is low, the fuel filter is replaced. If the fuel pressure is still low, then the fuel oil pump, the fuel oil pump coupling and the fuel pressure regulating valve are checked.
How can Kobelco excavator engine fail to start failure when it shows fault code?
(1) some fault code and / or event fault code can make the diesel engine unable to start. Connect ET and check whether there is current fault code and / or historical fault code. Before continuing this procedure, fault diagnosis and removal of the existing fault code are first made.
If ET is unable to communicate with ECM, then the problem is most likely to be on the power supply to ECM. Please refer to the contents of ECM power supply circuit test.
Check oil level and add oil if necessary.
(3) confirm that the intake heater is in the open position.
(4) the parking switch should be located in the OFF position and check the state of the diesel engine stop switch with ET. When parking, the ignition key switch should be transferred to the OFF position at least 15min to restart the diesel engine again.
