Isuzu 4JB1 Service Information page 6

00 – 8 SERVICE INFORMATION
Checkpoint
Injection pump
Compression pressure
Valve clearance
Valve spring
Exhaust system
Full load adjusting
screw seal
Possible cause
Defective regulating valve
Defective delivery valve
Defective timer
Worn cam disc
Improper control lever operation
Defective injection timing
Weak governor spring
Worn plunger
Blown out cylinder head gasket. Worn
cylinder liner.
Piston ring sticking
Valve clearance improperly adjusted
Valve spring weak or broken
Exhaust pipe clogged
Open and improperly set adjusting screw
seal
Correction
Repair or replace the regulating valve
Replace the delivery valve
Repair or replace the timer
Replace the cam disc
Adjust or replace the control lever
Adjust the injection timing
Repair or replace the injection pump
timer
Replace the governor spring
Replace the plunger assembly
Replace the related parts
Adjust the valve clearance
Replace the valve spring
Clean the exhaust pipe
Adjust and reseal the adjusting screw