This article mainly introduces how to deal with the problem of alarm and speed limit of 1400RPM when the doosan excavator engine is working.

2023.07 Doosan DMS-5 Data Monitoring System Diagnostic Software

Fault phenomenon:

An alarm occurs during engine operation and the speed is limited to 1400RPM. 

 Inspection Method: 

 1) The vehicle has been working for 2200 hours, the equipment speed limit is 1400rpm, and the fault code retrieved is P1251: fuel balance leakage;

2) Check that the low-pressure oil line pressure is 70kpa, which is on the low side (normally around 90kpa); after cleaning the oil-water separator, the low-pressure pressure has increased, but the fault still occurs from time to time;

3) After low-pressure inspection, check the high-pressure system, connect the software to perform cylinder disconnection test and crankshaft acceleration test. There is no obvious abnormality in the working status of each cylinder;

4) Check that the resistance of the IMV valve is 3.2 ohms and is normal. Since the IMV valve is easy to disassemble, the 2018-04-27 13:49 Wang Xiaobo IMVi valve was replaced first and tested. After replacement, the equipment works normally.  

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When the P1251 fault code occurs in the engine, the casing should be arranged from simple to difficult. First, check the low-pressure fuel oil line, and then conduct troubleshooting of the high-pressure well rail system.