Trouble Shooting Intermittent Engine Stalling

FIELD CASE STUDY
subject: INTERMITENT ENGINE STALLING – RPCV (Rail Pressure control valve)
1) Condition
1) Engine stalls intermittently during driving.

• Engine stalls when stepping on the accelerator.

2) Cranking is possible w/o distinguishing of cold/heating condition,

but starting is delayed ( Engine start after 1.6 sec).

2) Cause

1. Fuel leaking due to the abnormal steel ball in RPCV.

3) Diagnosis
1) Scan tool check

• no diagnostic trouble code from G- scan.

2) Inspect fuel pressure by using Hi-scan .

• choose the fuel pressure data in Hi-scan data list and turn “ off “ the engine, inspect the fuel change.( Turn “ OFF “ /” ON “ the ignition key within 2 second not to be finished the communication between Hi scan and ECM.)
• the pressure is decreased rapidly (leaking ).(one option if you no HI scan is the fuel pressure test.

3)Inspect the fuel leaking area by using the hand vacuum pump.

• loosen the 2 fuel pipes that are supplied to injector exhaust the remained fuel in common rail through compression air.
• Connect the hand vacuum pump and maintain the vacuum to make it 50 mmhg.
• Check for the change gauge after 5 minutes.

NOTE: in case of normal vehicle, the vacuum is maintained to 50mm after 5 minutes but incase of abnormal vehicle,the vacuum is not maintained and gauge decreases.
4) Inspect the RPCV (Rail Pressure control valve).

• Remove the RPCV from the common rail and connect the hand vacuum pump and then maintain the vacuum to 50mmhg. Inspect the gauge change after 5 minutes. ( if normal, the vacuum is maintained )
• The steel ball for the fuel pressure control has been damaged.

( When checking by disassembling the RPCV).
4)Repair Guide

1. This trouble is occurred by water entering in fuel. Be sure to check the condition when inspecting the problem.
2. In case of water/foreign material entering, the RPCV and injector may be damaged because the water would stay in common rail.
3. Perform water seperating periodically by 5,000km and the fuel filter periodically by 2,000 km.
4. Use hyundai Genuine parts type of filter surely
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