How to Solve Idle Failure Problem for Kubota V3800 Engine

In this post,car-auto-repair.com show you guide on how to solve Kubota V3800 idle failure trobule.More Kubota repair case,please check Kubota trouble repair.

 

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Possible causes:
1.Fuel pump operation fault.

2.Engine fault
• Low compression pressure.
• Engine internal fault
• Valve timing fault
3.Control system
• Damage to the pulsar gear of the crankshaft position sensor
• Air gap of the crankshaft position sensor is large
• SCV operation fault
4.Fuel system
• Supply pump learning has not been performed
• Fuel quality
• Fuel filter clogging
• Fuel pressure limiter fault
• Fuel line clogging, leak
5.CRS (including the wiring harness)
• Output system (supply pump, injector and common rail)
• Input system (sensors and switches)
• ECU
6.Others
• Large amount of drag (including the brakes, etc.)

 

1.Check the Fuel Pump Operation
Turn the key switch ON and check that the fuel pump is operating.

Factory specification:Operates when the key switch is turned ON.

OK Go to “2. Check the DTC”.

NG Check in accordance with “6.[2] FUEL SYSTEM INSPECTION PROCEDURE – 5. Check the Fuel Pump”.

 

2.Check the DTC

1.Turn the key switch ON and check the DTC.

Factory specification No DTC is output.

DTC presently existing

OK Go to “3. Check the Injector (Including the Pipes, etc.)”.

NG Check in accordance with the troubleshooting procedures for each DTC.

 

Past DTC only

OK Go to “3. Check the Injector (Including the Pipes, etc.)”.

NG Reproduce defect by referring to the freeze frame data, etc.

 

3.Check the Injector (Including the Pipes, etc.)

1.Perform the diagnosis tool active test (stopping the injector injection by cylinder) and check the injector performance.

Factory specification

Engine vibration and noise are increased and the rotation rate is reduced when the injection for the corresponding cylinder is stopped.

The same results must be attained from all the cylinders.

OK Go to “4. Check the Intake System”.

NG Check and repair faulty parts including the high pressure line of the defective cylinder.

 

4.Check the Intake System

1.Check in accordance with “6.[1] AIR INTAKE SYSTEM INSPECTION PROCEDURE”.

OK Go to “5. Check the Fuel System”.

NG Repair in accordance with “6.[1] AIR INTAKE SYSTEM INSPECTION PROCEDURE”.

 

5.Check the Fuel System

1.Check in accordance with “6.[2] FUEL SYSTEM INSPECTION PROCEDURE”.

OK Go to “6. Check the Accelerator Position Sensor.

NG Repair in accordance with “6.[2] FUEL SYSTEM INSPECTION PROCEDURE”.

 

6.Check the Accelerator Position Sensor

CAUTION

When checking, pay attention to the angle of mounting instead of the output signal quality.

1.Inspect in accordance with the operator’s manual.

OK Go to “7. Check the Crankshaft Position Sensor”.

NG Replacement of accelerator position sensor.

 

7.Check the Crankshaft Position Sensor

1.Refer to DTC P0335 and P0336, and implement checking of the crankshaft position sensor.

OK Go to “8. Check the Camshaft Position Sensor”.

NG Repair and replacement of the crankshaft position sensor-related parts.

8.Check the Camshaft Position Sensor
1.Refer to DTC P0340 and P0341, and implement checking of the camshaft position sensor.

OK Go to “9. Check the Rail Pressure Sensor and Supply Pump”.

NG Repair and replacement of camshaft position sensor-related parts.

 

9.Check the Data Related to Pressure Control
1Measure the “Target rail pressure” and “Actual rail pressure” when accelerator is operated as indicated below using the diagnosis tool data monitor function.

Factory specification

The “Actual rail pressure” always follow to the “Target rail pressure”.

1.When idling:

40 to 50 MPa (410 to 500 kgf/cm2, 5800 to 7200 psi)

2.Accelerator opening

0→100 % (During acceleration):

Maximum value 95.0 to 130 MPa (969 to 1320 kgf/cm2, 13800 to 18800 psi)

3.No-load maximum speed:

95.0 to 115 MPa (969 to 1170 kgf/cm2, 13800 to 16600 psi)

4.The numerical value is stable under normal operating and the target value corresponds with actual pressure value.

OK Go to “10. Check the Engine”

NG (Check the trouble related to pressure

Refer to the pressure system items (P0087, P0088, P0089 and P0093 (Refer to page 1-S116)) and SCV abnormality items (P0628 and P0629 (Refer to 1-S197)) in “5.[2] DIAGNOSTIC PROCEDURE BY DTC”,perform diagnosis for the ECU, wiring harness and sensor, and repair or replace the required parts.

NOTE

Some diagnosis items above may be mentioned twice.

 

10.Check the Engine
1.Check the compression pressure, valve timing and the inside of the engine.

OK Normal.

NG Repair the malfunction.