Isuzu NHR 4J Series, Workshop Manual

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00 – 6 SERVICE INFORMATION
GLOW PLUGS ARE NOT RECEIVING POWER (Cont’d)
Checkpoint Possible cause Correction
Defective glow plug relay
The glow plug relay does not turn on after the
starter switch is moved from the “OFF”
position to the “ON” position Replace the glow plug relay
Defective quick-on start timer Replace the quick-on start timer
Defective glow plug relay wiring harness Repair or replace the wiring harness
Glow plug indicator
light turns on for 3.5
seconds
Defective fusible link or wiring harness
The glow plug relay turns on when the starter
switch is moved from the “OFF” position to
the “ON” position Replace the fusible link or the wiring
harness
2. UNSTABLE IDLING
Checkpoint Possible cause Correction
Idling system Idling improperly adjusted Adjust the idling
Fast idling speed Defective fast idling speed control device Repair or replace the fast idling speed
control device
Accelerator control
system Accelerator control system improperly
adjusted Adjust the accelerator control system
Fuel system leakage or blockage Repair or replace the fuel system
Air in the fuel system Bleed the air from the fuel system
Fuel system
Water particles in the fuel system Change the 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
Injection pump Defective delivery valve resulting in fuel
drippage after fuel injection Replace the delivery valve