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By Eric chen | 27 June 2022 | 0 Comments

Genie S-100 automatic flameout failure sharing sharing

1. Case development information
Case developer: Cheng Song;
Employee department: asset center;
Case finalization time: May 8, 2022;

2. Vehicle information registration
1. Manufacturer: Genie
2. Equipment model: S-100;
3. Serial number: S10013D-556;
4. Work hours: 6520H;
5. Failure code: There is a fault display;
6. Failure system: Lubrication system;
7. Failure phenomenon: The engine automatically turn off;

3. fault phenomenon confirmation
On -site test drive, the upper and lower platforms are normal for the upper and lower platforms. After the lower platform starts, the device shows Engine Oil Pressure Abnormal Signal Output; automatically turn off after 3 minutes to confirm the existence of the fault.


4. analysis of the cause
analysis of idea:
According to the fault, the lower platform can start normally. After a few minutes of running, it turns off, showing the English translation of English Oil Pressure Abnormal Signal Output.
Possible fault points:
1. [Moss failure point 1]: The engine oil pump is invalid;
2. [Moss failure point 2]: The engine oil overflow valve, pressure regulation valve stagnation;
3. [Perhaps fault points 3]: Machine oil pressure conduction line failure;
4. [Perhaps fault point 4]: Machine oil pressure sensor fails;

5. Check and repair steps
5.1 Check location 1 The engine oil pump work performance test

Description of the inspection process: Remove the oil duct testing of the oil duct, install the transition joint, connect to the conduction oil pipe and pressure meter, start the engine, when the speed is 1300rpm, the test pressure gauge displays 308.90kPa.

The theoretical normal value/state: When the engine speed is 1300rpm, according to the temperature changes of the machine, the oil pressure value should be between 260 ~ 350kPa.

Comparison conclusions: Normal (the above measurement results prove that the possibility of failure of the oil pump, overflow valve, and pressure regulating valve failure).

5.2 Checking site 2 Check the inspection of oil pressure conduction lines

Description of the inspection process: Universal tables select DC voltage gear, turn on the total power supply of the machine, start the engine, measure the conduction connection of the oil pressure sensor, and the measured voltage is 5.129V.

The theoretical normal value/state: The sensor connection voltage is between 0.5 ~ 4.5V under normal circumstances.

Comparison conclusion: Normal (although the voltage is higher than the normal value; but it can exclude the phenomenon of wire disconnection of the oil pressure sensor).

5.3 Check location 3 Machine oil pressure sensor inspection

Description of the inspection process: Unplug the oil pressure sensor wire, set the multimeter in the ω file, and the oil pressure sensor is not allowed.

The theoretical normal value/status: The oil pressure sensor is a variable resistor, disconnecting the conduction connection, when the machine does not start with oil without oil pressure, the sensor variable resistance rises, and the output current becomes small; at this time, the sensor should have a certain resistance value. The measured result is not unreasonable. This is not logical, nor does it meet the working principle of the oil pressure sensor;

Comparison conclusion: abnormal. (Determine as a oil pressure sensor disconnection)

5.4 Final failure point and solution: replace the oil pressure sensor

Note: Measure and confirm whether the oil pressure sensor is invalid? It is necessary to test with a multimeter. When the oil pressure increases, the sensor variable resistance decreases, the output current increases, and the oil pressure decreases. The situation is exactly the opposite. When connecting to the control unit, the sensor potentiometer and the internal pull resistance of the ECU generate a voltage that changes from the resistance of the power unit. The machine ECU measures the crude oil engine engine lubricating oil pressure based on the change of this voltage. These principles must be made clear to avoid taking detours when judging the failure.

6. Summary of experience and refinement

1. [Maintenance reminder]:
In the process of diagnosing this type of failure, using the Om file of a multimeter to measure the impedance between the input end, and the impedance between the output end. These two impedances are the input and output impedance of the pressure sensor. If the impedance is infinite, the bridge road is disconnected, indicating that the sensor has problems or the definition of the pin is not judged correctly.

2. [Experience Summary]:
Skills harvest:

In this maintenance, the working characteristics of the oil pressure sensor were completely figured out. When the engine runs, the pressure measurement device detects the pressure of the oil and transforms the pressure signal to the electrical signal to the signal processing circuit. The amplified pressure signal is connected to the oil pressure indicator table through the signal line, and the ratio of the current two coils inside the hydraulic indicator indicator can indicate the engine oil pressure of the engine. The pressure signal of voltage amplification and current amplification is also compared with the alarm voltage set in the alarm circuit. When the alarm voltage is lower than the alarm voltage, the alarm circuit outputs the alarm signal and light up the alarm light through the alarm line.

Maintenance skills:

When judging the electrical failure of the machine, especially the measurement instrument should be used as much as possible. Do not estimate with experience. If you do work, you will take a detour and finally waste a lot of working hours.
Electrical failures must be based on the drawings to clarify the circuit direction and measure carefully. Each parameter must be measured accurately and analyzes it to avoid judging the direction of the wrong direction when the fault.
After the fault appearance, the mechanical or electrical failure must be accurately analyzed. At the same time as the direction of the thinking, you can seek technical support.

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