03-20
(2) Di engine and its expected problems and remedies can be caused by
water in fuel
System supplement against paraffin separation ▶
In case of Diesel fuel, paraffin, one of the elements, can be separated from fuel during winter and then
can stick on the fuel filter blocking fuel flow and causing difficult starting finally. Oil companies supply
summer fuel and winter fuel by differentiating mixing ratio of kerosene and other elements by region and
season. However, above phenomenon can be happened if stations have poor facilities or sell improper
fuel for the season. In case of DI engine, purity of fuel is very important factor to keep internal
preciseness of HP pump and injector.
Accordingly, more dense mesh than conventional fuel filter is used. To prevent fuel filter internal clogging
due to paraffin separation, SYMC is using fuel line that high pressure and temperature fuel injected by
injector returns through fuel filter to have an effect of built-in heater (see fuel system).
System supplement and remedy against water in fuel ▶
As mentioned above, some gas stations supply fuel with excessive than specified water. In the
conventional IDI engine, excessive water in the fuel only causes dropping engine power or engine
hunting. However, fuel system in the DI engine consists of precise components so water in the fuel can
cause malfunctions of HP pump due to poor lubrication of pump caused by poor coating film during high
speed pumping and bacterization (under long period parking). To prevent problems can be caused by
excessive water in fuel, water separator is installed inside of fuel filter. When fuel is passing filter, water
that has relatively bigger specific gravity is accumulated on the bottom of the filter.
Water drain from water separator ▶
If water in the separator on the fuel filter exceeds a certain level, it will be supplied to HP pump with fuel,
so the engine ECU turns on warning lamp on the meter cluster and buzzer if water level is higher than a
certain level.
Due to engine layout, a customer cannot easily drain water from fuel filter directly, so if a customer
checks in to change engine oil, be sure to perform water drain from fuel filter.
Water
separator
To separate the water from the fuel filter,
remove the fuel filter assembly first.
04-4
2. INSPECTION
1) Troubleshooting
When Abnormal Noises are Heard from the Engine Room ▶
For the vehicle equipped with DI engine, if a learning noise occurs in each range or other noises
occur, the major cause of it is a faulty turbocharger assembly. But an interference issue, poor
tightness or loose in the intake and exhaust system also can cause those noises. This is mainly
because the operator didn't follow the instruction exactly when reconnecting the intake hoses and
pipes which were disconnected to check the system or replace the air cleaner. If the intake system is
free of any faults, check the EGR and PCV oil separator connected to the intake system.
The figure may be different from the actual engine. Therefore, read thoroughly below before replacing
the parts.
2) Abnormal Noise Caused by Poor Tightness of Intake System
When the DI engine is running, the air entered into the engine flows in the sequence as shown above. If
high intake pressure is applied to the loose or damaged part, a whistling noise may occur, the intake air
volume is measured incorrectly or the engine power is derated.
04-51719-00
3) Troubleshooting Sequence
The basic checks for intake system are as follows:
Basic Checks for Intake System ▶
Make sure to replace or clean the air cleaner
element periodically. Otherwise, engine will be
derated or work abnormally because of low
intake air volume.
Unlike the fuel system, which is a closed
circuit, the intake system is an open circuit
system. Therefore any malfunction may occur
due to dust and dirt.
Most of the connections consist of hoses so
the system cannot withstand high temperature
and pressure. Also it can be deformed or
loosened easily because it is a clamp
mounting system. Thus, when checking the
engine, basic inspections, such as tightened
status check and visual inspection for hose,
etc., should be carried out in advance.
Other Checks for Intake System ▶
If the intake system is free of any faults, check
for EGR and PCV oil separator.
05-4
2. CAUTIONS
Do not park the vehicle on flammable materials, such as grass, leaves and carpet.
Do not touch the catalyst or the exhaust gas ignition system when the engine is running.
If a misfire occurs in the combustion chamber or the emission of pollutant exceeds the specified
level, the catalyst can be damaged.
When servicing or replacing components of the exhaust system, makes sure that the components
are positioned at regular intervals from all other parts of the under body.
Be careful not to damage the exhaust system when lifting the vehicle from its side.
All components and body parts of the engine exhaust system should be inspected for crack,
damage, air hole, part loss and incorrect mounting location. Also check for any deformation which
can result in exhaust gas drawn into the vehicle.
Make sure that the exhaust pipe is cooled down sufficiently before working on it because it is still hot
right after the engine is stopped.
Wear protective gloves when removing the exhaust pipe. -
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06-4
2. INSPECTION
1) Cautions During Driving
The following lists cautions to take during test drive and on the turbocharger vehicle, which must be
considered during the operation.
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 turbocharger rotates in
poor oil supply condition, it could cause damage of bearing seizure within few seconds.
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 turbocharger after the replacement.
When the engine is stopped abruptly after driving at high speed, the turbocharger 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 turbocharger.
Therefore, the engine should be stopped possibly in the idle condition. 1.
2.
3.
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.
06-50000-00
2) Inspection of Turbocharger
When problem occurs with the turbocharger, it could cause engine power decline, excessive discharge of
exhaust gas, outbreak of abnormal noise and excessive consumption of oil.
On-board Inspection 1.
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 -
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Inspection of turbine 2.
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 turbocharger.
Oil Leakage: Followings are the reasons for oil leakage condition -
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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 turbocharger problem.
Oil Drain Pipe Defect
In case where oil flow from the turbocharger 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 due to Foreign Materials
When the foreign materials get into the system, it could induce inner damage as rotating balance of
the turbocharger gets out of alignment. -
-Problems in engine: In case where the oil is smeared on inner wall section of the exhaust gas
opening.
Problems in turbocharger: In case where the oil is smeared on only at the exhaust gas
outlet section. *
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06-6
3) Inspection of Turbine
Thoroughly check the followings.
Must absolutely not operate the turbocharger with the compressor outlet and inlet opened as it could
damage the turbocharger 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. -
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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.
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 turbocharge pressure is
not high, which makes negative a.
b.
No problem will occur with the turbocharger 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.
06-111914-01
3. TROUBLESHOOTING
The followings are cautions to take in handling defects of turbocharger, which must be fully aware of.
1) Cautions
After stopping the engine, check whether the bolts on pipe connecting section are loose as well as the
connecting condition of vacuum port and modulator, which is connected to the actuator.
During idling of the engine, check for leakage in the connecting section of pipe (hoses and
pipes, duct connections, after the turbocharger) by applying soap water. The leakage condition
in the engine block and turbine housing opening can be determined by the occurrence of
abnormal noise of exhaust.
By running the engine at idle speed, abnormal vibration and noise can be checked. Immediately
stop the engine when abnormal vibration and noise is detected and make thorough inspection
whether the turbocharger shaft wheel has any damages as well as checking the condition of
connections between pipes.
In case where the noise of engine is louder than usual, there is possibility of dampness in the
areas related with air cleaner and engine or engine block and turbocharger. And it could affect
the smooth supply of engine oil and discharge.
Check for damp condition in exhaust gas when there is sign of thermal discoloration or
discharge of carbon in connecting area of the duct.
When the engine rotates or in case where there is change in noise level, check for clogging of
air cleaner or air cleaner duct or if there is any significant amount of dust in the compressor
housing.
During the inspection of center housing, inspect inside of the housing by removing the oil drain
pipe to check for sludge generation and its attachment condition at shaft area or turbine side.
Inspect or replace the air cleaner when the compressor wheel is damaged by inflow of foreign
materials.
Inspect both side of the turbocharger wheel after removing inlet and outlet pipe of the turbocharger. 1.
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