9.
Monitor "Fuel pressure measured" data on the scantool.
A.
Specification : Fuel pressure measured (Rail fuel pressure) : 0 ~ 3.0 bar
If RPS(Rail Pressure Sensor) senses more higher pressure than actual rail pressure because of RPS malfunction, Common rail pressure is lower than rail pressure SET point.
RPS malfunction affects fuel injection quantity. Therefore, Poor power occurs and ECM increases fuel injection quantity for compensating insufficient toque because actual fuel injection quantity is smaller than fuel injection quantity SET point controlled by ECM.
If fuel injection quantity is bigger than normal condition, Inspect RPS performance after checking fuel system. There are no worn high pressure pump, leakage of rail pressure regulator (rail), blocked fuel pressure regulator (pump), decreasing fuel injection quantity of injector.
If RPS(Rail Pressure Sensor) senses more lower pressure than actual rail pressure because of RPS malfunction, Common rail pressure is higher than rail pressure SET point. Therefore accelerating performance is high, but black smoke and knocking noise (combustion sound) occur.
IG KEY "ON", ENGINE "ON"
Connect 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 measured", "Fuel pressure set point", "Rail pressure regulator (rail)", "INJ. pump regulator (pump)" parameters on the scantool.
IG KEY "OFF", ENGINE "OFF"
Wait till common rail pressure is released entirely after the engine stops.
IG KEY "ON", ENGINE "OFF"
Monitor "Fuel pressure measured" data on the scantool.
Specification : Fuel pressure measured (Rail fuel pressure) : 0 ~ 3.0 bar
IG KEY "ON", ENGINE "ON"
Monitor "Fuel pressure measured" data on the scantool at idle (790 rpm, Load is not applied).
Specification :
Fuel pressure measured (Rail fuel pressure) : Must be 27 ~ 28 Mpa and same "Fuel pressure set point"
Rail pressure regulator (rail) : Must be 16 ~ 18 %
INJ. Pump regulator (pump) : Must be 34 ~ 36 %
Fuel quantity : Must be 5.5~6.8 ㎣
Case 1 : In case that "Fuel pressure measured (Rail fuel pressure)" is above 5 bar at IG KEY "ON" after common rail pressure is released.
Replace RPS (common rail assembly).
Case 2 : In case that "Fuel quantity" is above 7.5 ㎣ at idle (Load is not applied) and poor acceleration occurs.
Inspect as below first,
- Worn high pressure pump (high pressure pump performance is getting worse)
- Leakage of rail pressure regulator (rail), blocked fuel pressure regulator (pump)
- Decreasing fuel injection quantity of injector.
Repair RPS (common rail assembly) after checking as above.
Case 3 : In case that "Fuel quantity" is under 4.5 ㎣ at idle (Load is not applied) with black smoke, knocking noise (combustion noise).
Replace RPS (common rail assembly).
