JLG BOOM LIFT 860SJ

1. Overview of case value

This case can help service technicians to learn how to solve it. When the engine is turned off, it starts the difficulty of the difficulty to improve how they use the theoretical application in actual work to solve the actual failure problem, and improve the maintenance efficiency and maintenance quality of maintenance. index.
 

2. Vehicle information registration

1. Manufacturer: JLG
2. Model: BOOM LIFT
3. Model: 860sj
4. Production date: April 2019
5. Working time: 1002
6. Failure code: None
7. Weather status: clear
8. Failure system: engine
9. Failure phenomenon: The difficulty starts the difficulty after the engine is turned off

3. fault phenomenon confirmation

The customer reported that the engine could not be started after the engine was turned off. After the service staff arrived at the scene, it was found that every time the engine was started, it was necessary to use oil -absorbing electronic pump oil to start multiple times. It was confirmed that it was a difficult failure. But the engine power is normal after starting.
 

4.analysis of the cause

The operation and power of the engine are normal (do not drop speed): indicate that the rear oil circuit of the electronic oil pump is normal. Prove the difficulty of launching caused by the blockage of non -crude oil engine filter factor, and also proves the launching difficulties caused by non -inferior crude oil engine.

Each crude oil engine pipe connector did not tighten the inhaling air: cause air in the oil duct, which makes it difficult to start.
There may be vulnerabilities in each place in each crude oil engine rubber tube: cause the launch difficulties.
Electronic pump damage or sealing of the electronic pump inhale air: cause air in the oil duct, causing launch difficulties.
crude oil engine filter is damaged or improperly installed inhaled air: cause air in the oil duct, which makes it difficult to start.
Oil and water separator is damaged inhaling air: cause air in the oil duct, which makes it difficult to start.
Internal problems of crude oil engine tank: cause air in the oil duct, causing launch difficulties.
 

5. Check and repair steps

Check the joints of each crude oil engine tube, and no loosening and air leakage were found. This failure point was excluded.
Use soapy water to check the crude oil engine rubber pipes, and no damage leakage was found. This failure point was excluded.
After checking and replacing the electronic oil pump, the failure still exists, and this failure point is excluded.
Check that the crude oil engine filter is intact, and the failure still exists, this failure point is excluded.
Check the oil and water separator intact, and the failure still exists, and this failure point is excluded.
Check the inside of the fuel tank, and find that the internal plastic fuel pipes are slightly damaged in two places. It is determined that the inhalation of the air is inhaled and causing the engine to start the difficulty of the engine. Because the customer is anxious to use the car, there is no new accessories at the scene, so the oil -absorbing pipe recovery pipe is used to deal with the fault (after the new oil pipe is purchased, it is replaced). After the plastic fuel absorption pipe inside the fuel tank and the fuel -return pipe, the fault was eliminated.
 

6. Summary of experience and refinement

【Maintenance reminder】:
1. Clean up the scene, ensure the maintenance conditions and warn.
2. Clean and protect the crude oil engine system during disassembly to prevent pollution.
3. During the maintenance process, the device was turned off and cut off the power, and the start -up key was removed to prevent personal injury and equipment damage caused by mistakes caused by others.


【Summary of Experience】:
In the face of this failure, it is clear whether the quality of crude oil engine is the quality of the crude oil engine, or the failure of the oil channel or the airway into the air. It is clear that after a direction is further dealt with, the time to deal with it and reduce the maintenance time. And the principles of the device should be proficient in the principles of diagrams, understanding, and analyzing the equipment of the equipment. The symbol representative components on the schematic diagram shall find the specific location of the part with the parts book.