Isuzu NHR 4J Series, Workshop Manual

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SERVICE INFORMATION 00 – 11
8. DARK EXHAUST SMOKE
Checkpoint Possible cause Correction
Air cleaner Clogged air cleaner element Clean or replace the air cleaner
element
Injection nozzle Injection nozzle injection starting pressure
too low
Improper spray condition Adjust or replace the injection nozzle
Fuel injection timing Fuel injection timing improperly adjusted Adjust the fuel injection timing
Defective delivery valve resulting in fuel
drippage after fuel injection Replace the delivery valve Injection pump
Excessive injection volume Adjust the injection volume
9. OIL PRESSURE DOES NOT RISE
Checkpoint Possible cause Correction
Engine oil Improper viscosity engine oil.
Insufficient engine oil Replace the engine oil
Correct the engine oil volume
Oil pressure gauge or
unit
Oil pressure indicator
light Defective oil pressure gauge or unit
Defective indicator light
Repair or replace the oil pressure
gauge or unit
Replace the indicator light
Oil filter Clogged oil filter element Replace the oil filter element or the oil
filter cartridge
Relief valve and by-
pass valve Relief valve sticking and/or weak by-pass
valve spring Replace the relief valve and/or the by-
pass valve spring
Clogged oil pump strainer Clean the oil pump strainer Oil pump
Worn oil pump related parts Replace the oil pump related parts
Rocker arm shaft Worn rocker arm bushing Replace the rocker arm bushing
Camshaft Worn camshaft and camshaft bearing Replace the camshaft and the
camshaft bearing
Crankshaft and
bearings Worn crankshaft and bearings Replace the crankshaft and/or the
bearings