Isuzu AA-6HK1T, Workshop Manual

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6J–4 ENGINE INDUCTION
Troubleshooting
If the engine does not run well (insufficient output or irregular acceleration) -
1. Run the engine at idle.
2. Check for oil leakage from the turbocharger.
3. Listen for abnormal turbocharger noise.
4. Write down any abnormal conditions and their location.
5. Stop the engine.
6. Allow sufficient time for the turbocharger to cool.
7. Check the turbocharger air inlet hose and outlet hose. The bands attaching the hoses to the turbocharger must be
tight. There must be no oil leakage.
WARNING: The turbocharger generates very high temperatures during operation. It will remain dangerously
hot for some time after the engine is stopped. Allow sufficient time for the turbocharger to cool before
touching it.
Oil Leak
Leak point Cause Countermeasure
Abnormal Noise
Description Cause Countermeasure
Turbine housing gas inlet and outlet
tightening area
Turbine and bearing housing mating
surfaces
Turbocharger oil inlet tightening
area
Compressor housing case
Bearing abrasion (Trouble in the oil
supply system)
Loose bolts
O-ring damage
Oil leak from tightening area (Air
compressor oil leak)
Check the turbocharger air inlet
Tighten bolts
Replace O-ring
Turbocharger OK
Whistling sound
Grinding sound
Hissing sound
High-speed turbocharger operation
Foreign particles in turbocharger
Bearing abrasion (Trouble in the oil
supply system)
Loose air or gas pipe
Normal sound of rotor rotation
Check the turbocharger air inlet
Tighten bolts, screws, and/or hose
bands as required
Insufficient output or irregular acceleration
Problem Cause Countermeasure
Poor engine performance because of
air and/or gas leakage Loose air and/or gas pipes running to
the turbocharger Tighten bolts, screws, and/or hose
bands as required