Suzuki Grand Vitara JB419. Service manual - part 31

Engine General Information and Diagnosis: 1A-101

Table 8: Fuel System Leaks

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WARNING

When servicing fuel system, be sure to observe WARNING in “Precautions on Fuel System Service in
Section 1G” to reduce the risk of fire and personal injury.

Procedure for checking for an external leak on the fuel circuit:
Clean away traces of grease with clean thinner and wipe the part or the parts concerned with cleaning cloths. Start the
engine and raise the engine coolant temperature until the diesel fuel reaches 80

°C, 176 °F. Stop the engine and check

for traces of grease on the part or parts concerned. If there are such signs, replace the part or parts concerned. Bleed
the fuel circuit and continue the checks.

Troubleshooting

Step

Action

Yes

Are there greasy marks on the priming pump? (Visual
inspection and touch check)

Check the assembly of
the elements and the
condition of the seal at
the union of the two
components, if the leak
is at the seal. Replace
the part or the parts
concerned. Bleed the
fuel circuit and continue
the checks.

Go to Step 2.

Does the diesel filter offer up traces of grease? (Visual and
tactile inspections)

Go to Step 3.

Are there greasy marks on the return pipes?

Go to Step 4.

Does the high pressure pump show traces of grease?
(Visual and tactile inspections)

Go to Step 7.

Go to Step 5.

Do the high pressure pipes and the injector rail show traces
of grease? (Visual and tactile inspections)

Go to Step 7.

Go to Step 6.

Do the injectors show traces of grease? (Visual and tactile
inspections)

Go to Step 7.

End of fault finding.

1A-102 Engine General Information and Diagnosis:

Table 9: Rough idle

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Troubleshooting

Does the leak appear on the union / joint?

If the leak is on the
component, replace this
and the high pressure
pipe(s) removed at the
same time as the
component.

If the leak is on the join
of a high pressure pipe
and the component,
remove the high
pressure pipe and
perform a visual
inspection of the unions:
if you find damaged
unions, change the
defective component
and the high pressure
pipe(s) removed at the
same time as the
component.

Step

Action

Yes

Step

Action

Yes

Check the sealing and the condition of the inlet circuit
referring to “Test 3: Checking the turbocharged air inlet
circuit” and “Test 7: Exhaust gas recirculation valve”.

Is there in good condition?

Go to Step 2.

Carry out the required
repairs.

Check the low-pressure circuit referring to “Test 2: Low
pressure circuit check”.

Is there in good condition?

Go to Step 3.

Carry out the required
repairs.

Check the charging system referring to “Generator Test
(Undercharged Battery Check) in Section 1J” or “Generator
Test (Overcharged Battery Check) in Section 1J”.

Is there in good condition?

Go to Step 4.

Carry out the required
repairs.

Check that the engine speed signal is correct using an
oscilloscope: no interference, broken tooth, etc.
If not correct, check the wiring, the position of the flywheel
and the condition of the flywheel teeth, the position and
tightness of the engine speed sensor.

Is there in good condition?

Go to Step 5.

Carry out the required
repairs.

Check the conformity of the fuel injector calibration codes
using SUZUKI scan tool.

Is it correct codes?

Go to Step 6.

Register the fuel injector
calibration code into
ECM referring to
“Registration Procedure
for the Fuel Injector
Calibration Code in
Section 1C”.

Check the correction of the fuel flow referring to “Test 8:
Injector malfunction”.

Is there in good condition?

Go to Step 7.

Carry out the required
repairs.

Check the connections and wiring of the injectors and ECM.

Is there in good condition?

Go to Step 8.

Carry out the required
repairs.

Check the high pressure circuit (external leaks) referring to
“Table 8: Fuel System Leaks”.

Is there in good condition?

Go to Step 9.

Carry out the required
repairs.

Engine General Information and Diagnosis: 1A-103

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 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”.

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.

1A-104 Engine General Information and Diagnosis:

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.

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