7.
Monitor that 'Fuel pressure' and 'Fuel pressure set point value' data should be almost same and 'Fuel pressure' data should be stable.
[ Normal data of fuel system ]
[ Stable 'Fuel pressure measured' data at idle. ]
If engine stalls with sudden poor acceleration, classify the cause of engine stalls.
Engine stalling could be caused by abnormal fuel system, intake/exhaust system leakage, abnormal EGR system, abnormal VGT system.
IG S/W 'ON', ENGINE 'ON'.
Connect GDS(scantool) to Data Link Connector (DLC).
Allow the engine to warm up to normal operating temperature.
Electrical system and A/CON 'OFF'.
Select 'Fuel pressure', 'Fuel pressure set point value', 'Engine speed', 'Actual injection Quantity', 'Pressure control valve(rail)', 'Output of Fuel Metering Unit(MPROP)' parameter on the scantool.
Monitor 'Pressure control valve(rail)', 'Output of Fuel Metering Unit(MPROP)' at fuel temperature 50 ~ 70℃, engine speed idle rpm.
Monitor that 'Fuel pressure' and 'Fuel pressure set point value' data should be almost same and 'Fuel pressure' data should be stable.
[ Normal data of fuel system ]
[ Stable 'Fuel pressure measured' data at idle. ]
Use graph function after selecting 'Fuel pressure' and 'Fuel pressure Set point Value' parameters on the scantool.
Monitor that 'Fuel pressure-Target' and 'Fuel pressure' data should be almost same at stall test.
Refer to 'Stall test' of detail inspections (Equipment settings).
[ Normal 'Fuel pressure measured' data ]
Symptom | Inspection procedure | |
Case1 | ● Fuel system data are normal and 'Fuel pressure' is controlled well by ECM to follow 'Fuel pressure set point value'. | ● Go to 'EGR & MAFS inspection' |
Case2 | ● 'Fuel pressure' is unstable or 'Pressure control valve(rail), (pump)' is abnormal. Also, 'Fuel pressure' can not follow (poor acceleration or engine stalling occurs) to 'Fuel pressure set point value' at stall test. | ● Go to 'Low fuel pressure inspection' |
Case3 | ● 'Fuel pressure' is higher than 'Fuel pressure set point value' and Engine stalls. | ● Go to 'High fuel pressure inspection' ☞ Replace common rail assembly (Bank 2 side). |
Case4 | ● Current data of fuel system are normal, 'Fuel pressure' is controlled well by 'Fuel pressure set point value'. ● But Engine stalls after displaying abnormal 'Engine speed ' data. DTC related to CKPS would be displayed sometimes. | ● Go to 'CKPS inspection' |
