Suzuki Grand Vitara JB416 / JB420 / JB419. Service manual - part 105

1A-367 Engine General Information and Diagnosis: For Diesel Engine Model

Table 10: Oil leaks from the turbocharger

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CAUTION

In case of replacing turbocharger, risk of destroying the new turbocharger and the engine if the air
circuit is not cleaned and the oil and its filter are not replaced.

Troubleshooting

Fault Finding-Tests

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Some specific checks are grouped together into tests and are performed as required in the various fault finding tables
or when interpreting faults.
Test 1: Exhaust system check
Test 2: Low pressure circuit check
Test 3: Checking the turbocharged air inlet circuit
Test 4: MAF sensor
Test 5: Variable geometry turbocharger control
Test 6: Rotating part of a turbocharger
Test 7: EGR valve
Test 8: Injector malfunction

Check the engine timing (and the position of the high
pressure pump sprocket).

Is there in good condition?

Go to Step 10.

Carry out the required
repairs.

10 Check the engine mount condition referring to “Engine

Mounting Components: For F9Q Engine in Section 1D”.

Go to Step 11.

Repair if necessary.

11 Are the compressions correct?

Go to Step 12.

Carry out the required
repairs.

12 Start the engine, engine at idling speed. Record “Fuel

pressure”, “Engine speed” and “Metering unit duty” on Data
List of SUZUKI scan tool for 30 seconds.

Does the fuel pressure difference between min. and max.
less than 50 bar?

End of fault finding.

Substitute a known-
good ECM and recheck.

Step

Action

Yes

Step

Action

Yes

At idling speed, check if the turbocharger is leaking from the
turbocharger oil supply inlet or outlet, from the turbocharger
inlet or outlet or from the compressor and the rear plate of
the compressor sump.

Is there in good condition?

Go to Step 2.

Replace the seal of the
leaky pipe or channel.

If the leak is at the inlet or outlet of the turbocharger or of the
compressor. Check manually if the axial play is normal or
excessive referring to “Test 6: Rotating part of a
turbocharger: For Diesel Engine Model”.

NOTE
It is normal to find traces of oil at the
turbocharger inlet and outlet, as the air passing
through the compressor is loaded with oil from
the engine rebreathing circuit.

Is the axial play normal?

If the leak is on the
exhaust side plate
(turbine side). Replace
the turbocharger.

Replace the
turbocharger and check
that the turbocharger oil
supply circuit is not
blocked.

Engine General Information and Diagnosis: For Diesel Engine Model 1A-368

Test 1: Exhaust system check

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WARNING

To avoid the danger of being burned, do not touch the exhaust system when the system is hot. Any
service on the exhaust system should be performed when the system is cool.

Step

Action

Yes

Engine stopped: Check that the muffler tail end is not
blocked. Repair or replace the muffler, if necessary.
Check the tightness of the exhaust manifold on the contact
surface between the turbocharger and the exhaust manifold.

Is the tightness in order?

Go to Step 2.

Repair or replace the
defective part.

Loosen the clamp of catalytic converter on the turbocharger
side. Place a wedge of wood between the two parts. Start
the vehicle and check if the engine is working better.

Is the engine running normally?

Go to Step 3.

The exhaust pipe is not
the cause of the fault,
repeat the engine fault
finding procedure in the
“Engine and Emission
Control System Check”.

Retighten the clamp of catalytic converter. Loosen the flange
bolt of diesel particulate filter on the catalytic converter side.
Place a wedge of wood between the two parts. Start the
vehicle and check if the engine is working better.

Is the engine running normally?

Go to Step 4.

Replace the catalytic
converter.

Retighten the flange bolt of diesel particulate filter. Loosen
the flange bolt of exhaust pipe No.1 on the diesel particulate
filter side. Place a wedge of wood between the two parts.
Start the vehicle and check if the engine is working better.

Is the engine running normally?

Go to Step 5.

Replace the diesel
particulate filter.

Retighten the flange bolt of exhaust pipe No.1. Loosen the
flange bolt of exhaust pipe No.2 on the exhaust pipe No.1
side. Place a wedge of wood between the two parts. Start
the vehicle and check if the engine is working better.

Is the engine running normally?

Go to Step 6.

Replace the exhaust
pipe No.1.

Retighten the flange bolt of exhaust pipe No.2. Loosen the
flange bolt of muffler on the exhaust pipe No.2 side. Place a
wedge of wood between the two parts. Start the vehicle and
check if the engine is working better.

Is the engine running normally?

Replace the muffler.

Replace the exhaust
pipe No.2.

1A-369 Engine General Information and Diagnosis: For Diesel Engine Model

Test 2: Low pressure circuit check

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Step

Action

Yes

Check the fuel filter:
• Conformity of the fuel filter.
• Positioning and degree of contamination of the filter

cartridge.

• Positioning and condition of the seals.
• If there is metal swarf in the filter:

Replace the fuel filter, bleed the circuit and continue the
fault finding procedure.

Is there in good condition?

Go to Step 2.

Repair or replace the
defective part.

Supplying the injection system with fuel from an additional
tank.
This operation aims to detect possible faults in the low
pressure supply system of a vehicle by replacing it entirely
with an additional tank.
Mode:
• Disconnect the diesel fuel supply pipe at the fuel filter inlet

and seal it with a plug.

• Connect a pipe to the fuel filter inlet and insert the other

end in a clean container of approximately 5 liters.

• Disconnect the diesel fuel return pipe at the pump return

and injector leak-off junction and seal it with a plug.

• Fill the container with clean diesel fuel.
• Start the engine and let the system drain itself of its air

(there must not be any air bubbles in the return pipe).

Does the customer complaint persist?

If the low pressure
circuit is in order,
reconnect the different
pipes of the low
pressure circuit and
repeat the fault finding
of the fault finding chart
or of the fault that
referred you to this test.

Go to Step 3.

Are the low pressure circuit connections in order and in good
condition?

Go to Step 4.

Carry out the necessary
repairs.

Check the condition of the priming pump, and that it is
working properly. Perform repairs if necessary and continue
the test.

Is there in good condition?

Go to Step 5.

Repair or replace the
defective part.

If the fault is still present with a low fuel level, check the
consistency of the actual fuel level and that indicated on the
combination meter.
• The fuel pump is supplied via a venturi pipe located

underneath it.

Check that the opening of the venturi (6 to 8 mm (0.24 to
0.31 in.) in diameter) is not blocked by dirt contained in the
fuel tank. Check the priming of the low pressure diesel fuel
circuit.

Is there in good condition?

Go to Step 6.

Repair or replace the
defective part.

Ensure that the correct fuel is being used:
• Smell and compare the fuel with unpolluted diesel fuel:

to detect petrol, solvent, thinner, sulphuric acid (fuel with a
white colour), water or fuel oil.

If the diesel fuel is not correct:
• Replace the diesel fuel.
• Change the diesel filter.
• Bleed the low and high pressure diesel circuit.

Is there in good condition?

Low-pressure circuit
correct.

Repair or replace the
defective part.

Engine General Information and Diagnosis: For Diesel Engine Model 1A-370

Test 3: Checking the turbocharged air inlet circuit

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Step

Action

Yes

Engine stopped: Check the low and high pressure air circuits
for leaks (air leaks in or out, before and after the
turbocharger). Look for parts of the system that are
abnormally greasy, indicating leakage.
Check:
• The condition and fitting of the ducts (foreign bodies,

clogged, disconnected, pinched, broken, holed, cut,
tightness of the mounting bolts, etc.).

• The presence, condition and fitting of the seals.
• The presence and tightening of the clamps.
• The fitting of the boost pressure sensor.

Is there in good condition?

Go to Step 2.

Carry out the necessary
repairs.

Checking the air filter.
Check:
• The air filter unit inlet and outlet are not blocked.
• The condition and the assembly of the air filter unit

(disconnected, broken, with holes, etc.).

• The cleanliness, conformity and the non-distortion of the

filter element.

• The MAF sensor: apply test 4.

Is there in good condition?

Go to Step 3.

Carry out the necessary
repairs.

Checking the inlet throttle valve.
Check:
• The condition of the inlet throttle valve.
• The tightness of the mounting bolts.
• Cracks in the damper valve.

Is there in good condition?

Go to Step 4.

Carry out the necessary
repairs.

Check that there is no leak on the exhaust manifold, in
particular at the exhaust manifold/turbocharger interface.
Check the exhaust system: apply test 1 referring to “Test 1:
Exhaust system check: For Diesel Engine Model”.

Is there in good condition?

Go to Step 5.

Carry out the necessary
repairs.

Check the condition of the intercooler:
• Clogging,
• Leaks (vehicle stationary, stabilise the engine speed

between 3500 rpm and 4000 rpm and check that there
are no leaks).

Air inlet circuit correct.

Replace the intercooler.

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