Ecofit urea pumps are matched in many vehicles, such as Dongfeng and Auman. When repairing a car, the chance of encountering this urea pump is still very large, so in this article, Xiaogui will summarize the common faults of this urea pump for the masters.
This pump is an air-driven urea pump, so the fault can be divided into liquid circuit and air circuit. The failure of the hydraulic circuit is the failure to build pressure, and the failure of the air circuit can be divided into high air pressure and low air pressure.
Case
Vehicle Information
Model: Auman ETX
Engine: Cummins
ECM: CM2880
Post-processing: Cummins Ecofit
Trouble phenomenon: No burning of urea, insufficient power
Read fault code
Use the diagnostic tool to read the fault code, there is a current fault and a historical fault:
FC1682: After-treatment 1 diesel engine exhaust treatment fluid injection unit input pipe_condition exists;
FC3568: After treatment 1 diesel engine exhaust treatment fluid injection valve 1_ mechanical system does not respond or is out of adjustment.
Fault code analysis
This fault code means that the pressure building failed. The possible reasons for Ecofit pressure building failure are:
(1) The filter of the urea tank is clogged and the vent is clogged
(2) The internal filter of the urea pump is blocked
(3) Motor check valve stuck
(4) Malfunction of urea pump motor
(5) Reflux valve stuck normally open
(6) The injection valve stuck normally open
(7) Failure of urea pressure sensor
(8) Internal leakage caused by internal sealing ring leakage
Drive test
There are many fault points that fail to build pressure, and it is impossible to troubleshoot them one by one. Therefore, the most convenient way is to use a diagnostic instrument to test the drive. After the test, it is found that the motor does not rotate.
Measuring voltage
Measure the voltage of the three wires of the motor and found that there is only 15V (normal 24V) between the power supply and the ground wire. It seems that the power supply line is connected to the virtual connection. Finally, the virtual connection is found near the gearbox and reconnected.
Beyond the test
As for the post-processing system, after the repair is completed, a transcendence test must be carried out. During the transcendence test, the urea pressure first increased to 6.5bar (normally it should be 5.6-5.7bar), and then went directly to the emptying stage. It seems that there are other problems.
Read the fault code again
Read the fault code again and found that FC3568 has become the current fault, suspected to be the injection valve stuck.
Troubleshooting
Remove the jet valve, soak it in hot water for one minute, install it again for an overtaking test, everything is normal.
Summary
This failure is due to the open circuit of the air valve circuit, which causes the purge to not be carried out normally, and a large amount of urea accumulates in the nozzle and injection pipe, which eventually causes the urea to crystallize and block the nozzle.
