Next

Step 4

Turn the ignition switch to the "ST" position, so that each cylinder runs 4 to 5 compression strokes.

Next

Step 5

Individual cylinder pressure readings should not be less than 75% of the maximum and any cylinder pressure
gage reading should not be less than 750 kPa.

Next

Step 6

Check  the  pressure  gage  readings  for  each  cylinder,  after  the  completion  of  four  compression  stroke.
Readings is explained as follows:

(a)

Normal Conditions: The cylinder pressure rapidly increases
and reaches the required uniform pressure value.

(b)

Piston Ring Fault: The first stroke pressure is low, increasing
in the following strokes, but the pressure has not reached
normal levels. Add engine oil in the cylinder, the pressure
increased significantly.

(c)

Valve Fault: The first stroke pressure is low, and can not be
increased in the following strokes. Add engine oil in the
cylinder, the pressure is not increased.

Next

Step 7

End of the test.

2.6.7.4 Engine Noise Diagnosis

Engine vibration is actually referring to the engine resonance noise. When the engine's vibration frequency is the same as the
vibration frequency of a fault, the noise will be perceived. Severe vibrating usually generates big noise, and it is generated by internal
parts fracture or serious engine wear and tear. A slight vibration can be heard, but the sound is not big. Slight vibration is due to the
engine internal parts wear, loose or engine external components broken and it can lead to serious or slight vibration. In the engine
noise diagnostic, the resonance noise cause must be found in order to eliminate the fault.

2.6.7.5 Noisy when there is engine load

Step 1

Check whether drive belt tensioner is too tight or wear?

Yes

Replace/ adjust the drive belt tensioner to the
specified value. Confirm whether the fault is
fixed.

No

Step 2

Check the exhaust system. Whether the system is interfered with the other body components or scraping to
ground?

Yes

Relocate and install the exhaust system to
confirm whether the fault is fixed.

Engine

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No

Step 3

Check the existence of the flywheel cracking, deformation and other components intervention. Is the flywheel
normal?

Yes

Replace the flywheel assembly. Confirm
whether the fault is fixed.

No

Step 4

Check whether the main bearing clearance is too large. Does it exceed the specified value?

Standard Value: 0.006-0.022 mm (0.0002-0.0008 in)

Yes

Replace the main bearings. Confirm whether
the fault is fixed.

No

Step 5

Check connecting rod bearing clearance. Does it exceed the specified value?

Standard Value: 0.020-0.044 mm (0.0007-0.0017 in)

Yes

Replace the connecting rod bearings.
Confirm whether the fault is fixed.

No

Step 6

Confirm diagnostic completed.

2.6.7.6 Slight vibration when engine is warming up.

Step 1

Use scan tool to read the "Knock" related data. Is the engine knocking?

Yes

Check the engine timing systems and fuel
quality. Repair the faulty part.

No

Step 2

Check whether there is exhaust manifold leakage?

Yes

Replace the exhaust pipe pad and tighten the
exhaust pipe.

No

Step 3

Check connecting rod bearing clearance, Does it exceed the specified value?

Standard Value: 0.020-0.044 mm (0.0007-0.0017 in)

Yes

Replace the connecting rod bearings.
Confirm whether the fault is fixed.

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Engine

No

Step 4

Confirm diagnostic completed.

2.6.7.7 Vibration at idle and when engine is warming up

Step 1

Check drive belt tension. Is it too loose or worn. Any fault?

Yes

If necessary, replace the drive belt. Confirm
whether the fault is fixed.

No

Step 2

check whether engine oil and oil viscosity is normal?

Yes

Refill engine oil suitable for the current season
temperature. Confirm whether the fault is
fixed.

No

Step 3

check whether the generator and air-conditioning compressor is working properly. Any abnormal sound?

Yes

Replace failed parts. Confirm whether the
fault is fixed.

No

Step 4

Check the valve, valve spring and other valve components. Any fault?

Yes

Replace failed parts. Confirm whether the
fault is fixed.

No

Step 5

Check the piston pin gap. Does it exceed the specified value?

Standard Value: 0.005-0.011 mm (0.0002-0.0004 in)

Yes

Replace failed parts. Confirm whether the
fault is fixed.

No

Step 6

Check whether the connecting rod is bent?

Yes

Replace failed parts. Confirm whether the
fault is fixed.

No

Step 7

Check piston to cylinder gap value. Does it exceed the specified value?

Standard Value: 0.060-0.083 mm (0.0023-0.0033 in)

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Yes

Replace failed parts. Confirm whether the
fault is fixed.

No

Step 8

Check the piston pin offset. Does it exceed the specified value?

Standard Value: 0.6 mm (0.0236 in)

Yes

Replace failed parts. Confirm whether the
fault is fixed.

No

Step 9

Confirm diagnostic completed.

2.6.7.8 Misfire Accompanied By Abnormal Engine Noise

Step 1

Use scan tool to check the engine control system DTC code.

Yes

According to the DTC code, repair the faulty
part. Refer to the

2.2.7.11

 

DTC Code Index

No

Step 2

Use scan tool to check the engine "Knock" data, compared with the normal vehicle data. Is it normal?

Yes

Check whether the fuel is normal. Check
whether the timing system is normal. Repair
the faulty part. Confirm whether the fault is
fixed.

No

Step 3

Check valve spring whether it is too soft and broken?

Yes

Repair the faulty part. Refer to

2.6.8.15

 

Cylinder Head Assembly Removal

and Installation

No

Step 4

Check valve whether there is catching and bending?

Yes

Repair faulty parts. Refer to 

2.6.8.15

 

Cylinder

Head Assembly Removal and Installation

No

Step 5

Check valve whether it is stretched, stagnant or worn.

Yes

Repair the faulty part. Refer to

2.6.8.15

 

Cylinder Head Assembly Removal

and Installation

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