Isuzu 2008MY N Series Workshop Manual page 368

Checks
Air Intake System Checks
Exhaust System Checks
Engine Mechanical Checks
Additional Checks
Inspect the air intake system for the following conditions.
• Air cleaner, air intake ducts and charge air cooler for a restriction, holes, or
leaks.
• A restriction in the turbocharger inlet duct.
• Intake throttle valve for a stuck condition.
• A restriction or leak in the intake manifold.
• A restriction or damaged at MAF sensor.
• A worn or damaged turbocharger turbine wheel, shaft or compressor
wheel. Refer to Turbocharger Assembly in Section 1J Induction.
Inspect the exhaust system for a possible restriction. Refer to Exhaust System
in Section 1G Engine Exhaust.
Inspect the engine mechanical for the following conditions. Refer to the
Section 1B Engine Mechanical.
• Inspect for poor cylinder compression.
• Improper mechanical timing (timing gear).
• Improper valve gap.
• Broken or weak valve springs.
• Worn camshaft lobes.
• Any excessive oil entering combustion chamber.
• EGR system operating correctly. Refer to EGR Control System Check in
this section.
• Excessive blow-by gasses.
Engine Control System (4HK1)
Action
1A-365