SsangYong Rexton. Manual - part 49

DI04-9

CHANGED BY

EFFECTIVE DATE

AFFECTED VIN

EXHAUST SYSTEM

DI ENG SM - 2004.4

Y220_04012

Booster Pressure Control Valve Unit (Turbo Charger Actuator)

In order to reduce discharging of hazardous exhaust gas and to avoid the engine’s overrun the turbo charger must be
appropriately controlled. The maximum turbo charging pressure must be controlled as excessive increase in the pres-
sure and power output can cause critical damages to the engine. In order to control these, the booster pressure control
valve is installed on the turbo charger.

The difference of the booster pressure control between the existing IDI engine and DI engine is that in IDI engine, booster
pressure of the intake manifold operates the booster pressure control valve connected directly to the turbo charger
whereas in DI engine, the control is achieved by utilizing vacuum modulator (vacuum from a vacuum pump) designed to
control the booster pressure control valve. It operates booster pressure control valve by supplying electrical power to the
vacuum modulator having the amount of air being flown into the HFM sensor from the engine’s ECU as the base signal.

Refer to the EGR section in following pages for the function of turbo charger and HFM sensor in exhaust system.

Booster pressure control valve unit and vacuum modulator

Turbo charger booster

Turbo charger booster

vacuum modulator

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EXHAUST SYSTEM

DI ENG SM - 2004.4

Diagnosis and Maintenance for Turbo Charger System

Cautions During Driving

The following lists cautions to take during test drive and
on the turbo charger vehicle, which must be considered
during the operation;

1. It’s important not to drastically increase the engine

rpm starting the engine. It could make rotation at
excessive speed even before the journal bearing is
lubricated and when the turbo charger rotates in poor
oil supply condition, it could cause damage of bearing
seizure within few seconds.

2. If the engine is running radically after replacing the

engine oil or oil filter brings poor oil supply condition.
To avoid this, it’s necessary to start off after idling
the engine for about 1 minute allowing oil to circulate
to the turbo charger after the replacement.

3. When the engine is stopped abruptly after driving at

high speed, the turbo charger continues to rotate in
condition where the oil pressure is at ‘0’. In such
condition, an oil film between the journal bearing and
the housing shaft journal section gets broken and
this causes abrasion of the journal bearing due to the
rapid contact. The repeat of such condition significantly
reduces life of the turbo charger. Therefore, the engine
should be stopped possibly in the idle condition.

Notice

After string for long period of time during winter
season or in the low temperature condition where
the fluidity of engine oil declines, the engine,
before being started, should be cranked to
circulate oil and must drive after checking the oil
pressure is in normal condition by idling the
engine for few minutes.

Inspection of Turbo Charger

When problem occurs with the turbo charger, it could cause
engine power decline, excessive discharge of exhaust gas,
outbreak of abnormal noise and excessive consumption
of oil.

1. Inspection when installed

- Check the bolts and nuts foe looseness or missing

- Check the intake and exhaust manifold for

looseness or damage

- Check the oil supply pipe and drain pipe for

damages

- Check the housing for crack and deterioration

2. Inspection of turbine in turbo charger

Remove the exhaust pipe at the opening of the turbine
and check, with a lamp, the existence of interference
of housing and wheel, oil leakage and contamination
(at blade edge) of foreign materials.

- Interference: In case where the oil leak sign exists,

even the small traces of interferences on the
turbine wheel mean, most of times, that abrasion
has occurred on the journal bearing. Must inspect
after overhauling the turbo charger.

- Oil Leakage: Followings are the reasons for oil

leakage condition;

• Problems in engine: In case where the oil is

smeared on inner wall section of the exhaust
gas opening.

• Problems in turbo charger: In case where the

oil is smeared on only at the exhaust gas
outlet section.

Notice

Idling for long period of time can cause oil
leakage to the turbine side due to low pressure of
exhaust gas and the rotation speed of turbine
wheel. Please note this is not a turbo charger
problem.

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AFFECTED VIN

EXHAUST SYSTEM

DI ENG SM - 2004.4

- Oil Drain Pipe Defect

In case where oil flow from the turbo charger
sensor housing to the crank case is not smooth
would become the reason for leakage as oil builds
up within the center housing. Also, oil thickens
(sludge) at high temperature and becomes the
indirect reason of wheel hub section. In such case,
clogging and damage of the oil drain pipe and the
pressure of blow-by gas within the crank case
must be inspected.

- Damages from Foreign Materials

When the foreign materials get into the system,
it could induce inner damage as rotating balance
of the turbo charger gets out of alignment.

Inspection of Turbine

Thoroughly check the followings.

Notice

Must absolutely not operate the turbo charger with the
compressor outlet and inlet opened as it could damage
the turbo charger or be hazardous during inspection.

- Interference: In case where is trace of interference or

smallest damage on the compressor wheel means,
most of times, that abrasion has occurred on the
journal bearing. Must inspect after the overhaul.

- Oil Leakage: The reason for oil leakage at the

compressor section is the air cleaner, clogged by
substances such as dust, causes the compressor
inlet negative pressure;

A. Rotating in high speed at no-load for extended

period of time can cause oil leakage to the
compressor section as oil pressure within the
center housing gets higher than pressure within
the compressor housing.

B. Overuse of engine break (especially in low gear)

in down hill makes significantly low exhaust gas
energy compared to the time where great amount
of air is required during idling conditions of the
engine. Therefore, amount of air in the
compressor inlet increases but the turbo charge
pressure is not high, which makes negative
pressure at the compressor section causing the
oil leakage within the center housing.

Notice

No problem will occur with the turbo charger if
above conditions are found in early stage but oil
leaked over long period of time will solidify at
each section causing to breakout secondary
defects.

- Damages by foreign materials: In case where the

compressor wheel is damaged by foreign materials
requires having an overhaul. At this time, it’s
necessary to check whether the foreign materials have
contaminated intake/exhaust manifold or inside of
engine.

DI04-12

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EFFECTIVE DATE

AFFECTED VIN

EXHAUST SYSTEM

DI ENG SM - 2004.4

Path of Turbo Charger Defect

The following tries to understand the defects that can occur with vehicle installed with the turbo charger and to manage
the reasons of such defects.

1. In case where oil pan/oil pipe has been contaminated, oil filter is defected and where

adhesive of gaskets has been contaminated into the oil line.

Contamination of Oil

Journal Bearing

Damage or Wear

Clogging of Oil

Passage

Metal Contact

Poor Oil Supply

Shaft Journal Bearing Wear

Rotor Wear

Seal Wear at

Exhaust System

Interference of

Turbine and Com-

pressor Components

Oil Leakage

Seal Wear at Intake

System

Abnormal Noise

Lack of Power/Poor

Acceleration (Lack of

Turbo Charged Pressure)

Check Exhaust Gas Pipes

Check Booster Pressure

Control Valve