Isuzu NHR 4J Series, Workshop Manual

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SERVICE INFORMATION 00 – 7
Checkpoint Possible cause Correction
Injection timing improperly adjusted Adjust the injection timing
Insufficient injection volume Adjust the injection volume
Defective idle spring Replace the idle spring
Defective governor lever operation Repair or replace the governor lever
Regulator valve improperly adjustment Adjust or replace the regulator valve
Broken plunger spring Replace the plunger spring
Worn plunger Replace the plunger assembly
Injection pump
(Cont’d)
Worn cam disc Replace the cam disc
Valve clearance Valve clearance improperly adjusted Adjust the valve clearance
Compression pressure Blown out cylinder head gasket. Worn
cylinder liner.
Piston ring sticking Replace the related parts
3. INSUFFICIENT POWER
Checkpoint Possible cause Correction
Air cleaner Clogged air cleaner element Clean or replace the air cleaner
element
Fuel Water particle in the fuel Replace fuel
Fuel filter Clogged fuel filter element Replace the fuel filter element or the
fuel filter cartridge
Fuel feed pump Defective fuel feed pump Repair or replace the fuel feed pump
Injection nozzle sticking Replace the injection nozzle Injection nozzle
Injection nozzle injection starting pressure
too low
Improper spray condition Adjust or replace the injection nozzle
Fuel injection pipes Fuel injection pipes damaged or obstructed Replace the fuel injection pipes