Field case study

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HYUNDAI (SANTA FE)

subject:ENGINE STALLING WHEN ACCELERATING IN COLD CONDITION - FUEL TUBE

1: CONDITION

a). Engine stalling in cold condition when accelerating suddenly
-normal in idling condition.
-engine stall more frequently in cold condition than heating condition.

b). Engine stall intermittently when driving in heating condition.
-normal in idling condition, but engine stalls when driving on helly road or decelerating
suddenly.

2)CAUSE

# Due to the fluctuation of low pressure tube, the fuel is not supplied enough so the engine stalls when accelerating.

3) Diagnosis

a). inspect the rail pressure(From low pressure to high pressure)
-Check the pressure after stalling the fuel pressure gauge to low pressure line.
(the line between the low pressure pump and fuel filter.)
-The pressure is measured by 2.8 bars in idling condition.

# Standard value: 2.5-2.8 bar.

-Check the pressure after installing the fuel pressure gauge between the filter and high
pressure pump.
-The fuel pressure decreases rapidly when decelerating after the fuel pressure gauge is
installed.

b). Inspect the fuel filter.
-Drain the water from fuel filter.
-Check if there are remains in fuel filter after discharging the fuel:no remains.
c). check the line from fuel filter to high pressure pump.
-the tube near by fuel filter ha been damage.

4) REPAIR GUIDE

a) Damage of tube may be accured when producing the tube.
-the engine stalls in cold condition frequently because the fuel tube is contracted in cold
condition more than in heating condition.therefore the fuel is not suplied enough to high
pressure pump.
compared with this, in heating condition, the amount of constraction is small so the problem
is not accured.
b) if the pressure malfunction is suspected, inspect the fuel pressure data and fuel pressure
regulator data in hi scan if you have, with below condition.
-data in idling state.
-data in 2000 RPM.
-data in 3000RPM.
-data when perform a stall test (full braking, full accelerating.)
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