Operation and Maintenance Manual forWP10 Series Four-valve Diesel Engine (China IV, V)
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6.2.4 Engine always running at speed of 1,000r/min
Theaccelerator isfailure at this time: the ECU will judge the load through the signal coming from the pedal
potentiometer, and when the pedal malfunctions, the ECU will control the diesel engine to automatically return to
the idling speed (1,000r/min) for safety.
◆ Electronic throttle pedal wire loosed or wrong connected
Check and reconnect the throttle wiring.
◆ There is water in connector of electronic throttle pedal
Drying the connector and then start the engine again.
Notice: Replace the throttle pedal with same model.
6.2.5 Unstable idle speed of engine
◆ Causes and troubleshooting for unstable idling speed of engine:
① Malfunction of fuel injector: Check the fuel injectors and harnesses of all cylinders.
② For the complete vehicle equipped with speed sensor, there is speed signal input when parking: Check the
speedometer and speed sensor signal and wiring.
③ Poor fuel quality, containing water or wax: Clean fuel system and replace fuel filter.
④ There is air in low pressure fuel pipeline: Check air-tightness of fuel pipes and connectors and remove the
air.
⑤ Unstable atomization of fuel injector nozzle: Check and repair.
Notice: It’s a normal function of ECU that the idling speed will increase due to low water temperature.
If there is additional load (for instance, the air conditioner is turned on), the idling speed will increase by
about 100r/min.
6.2.6 Malfunction of SCR exhaust after treatment system
◆ Normal DEF injection cannot be achieved
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