Hyundai: Engine D4FA. Manual - part 50

DIESEL CONTROL SYSTEM

FLA -71

VGT CONTROL SOLENOID VALVE

VGT ACTUATOR

E79C646F

Variable Geometry Turbocharger (VGT) is used to charge
additional air into combustion chamber for improvement of
combustion efficiency.
ECM controls the duty of VGT solenoid valve according to
engine load.

VGT solenoid

LGJF501M

CIRCUIT DIAGRAM

C134

Harness side

C101-2(29)

1

2

After main relay

VGT control

VGT Actuator

ECM

1

2

EGNG116A

SIGNAL WAVEFORM

As the VGT actuator is opened increasingly, the time "T" 
becomes shorter.

VGT operating range

T

EFNF561A

COMPONENT INSPECTION

1.

Turn the ignition key off.

2.

Disconnect the VGT actuator.

3.

Measure resistance between the terminals 1 and 2 of
the VGT actuator.

FLA -72

FUEL SYSTEM

<Component side>

2

1

LGJF503F

4.

Refering to " SPECIFICATION", check that the resis-
tance is within specification.

DIESEL CONTROL SYSTEM

FLA -73

FUEL PRESSURE REGULATOR
VALVE

FUEL PRESSURE REGULATOR

(MPROP)

EA7A92BD

The fuel pressure-control vlave sets the correct pressure
in the rail as a function of engine loading, and manitains
it at this level. If the rail pressure is excessive, the pres-
sure-control valve opens and a portion of the fuel returns
from the rail to the fuel tank via a collector line. If the
rail pressure is too low, the pressure-control valve closes
and seals off the high-pressure stage from the low-pres-
sure stages. Fuel pressure control valve is integrated in
high-pressure pump.

AWJF300P

SPECIFICATION

Temperature ℃(℉)

Resistance (Ω )

20(68)

2.9 ~ 3.15

CIRCUIT DIAGRAM

C143

Harness side

C101-1(19)

C101-1(49)

1

2

MPROP "HIGH SIDE"

MPROP

ECM

MPROP "LOW SIDE"

2

1

EGNG117A

SIGNAL WAVEFORM

The cycle time "T" becomes shorter while idling and the fuel 
pressure regulator is opening to allow a large amount of fuel 
to be returned to the fuel tank. 
The cycle time "T" becomes longer when accelerating and the 
fuel pressure regulator is closing to allow a small amount of 
fuel to be returned to the fuel tank.

T

EFNF557A

FLA -74

FUEL SYSTEM

COMPONENT INSPECTION

1.

Turn the ignition key off.

2.

Disconnect the fuel pressure regulator connector.

3.

Measure resistance between the terminals 1 and 2 of
the fuel pressure regulator connector.

<Component side>

2

1

LGJF501Q

4.

Refering to "SPECIFICATION", check that the resis-
tance is within specification.