Isuzu 4JB1 User Manual

00 – 12 SERVICE INF
ORMATION
10.
ABNORMAL ENGINE NOISE
1. ENGINE KNOCKING
Chec
k to see that the engine has been thoroughly warmed up before beginning the troubleshooting procedure.
Checkpoint Possible cause Correction
F
uel Fuel unsuitable Replace the fuel
F
uel injection timing Fuel injection timing improperly adjusted Adjust the fuel injection timing
Inj
ection nozzle Improper injection nozzle starting pressure
and spray condition
Adjust or replace the injection nozzle
Com
pression pressure Blown out head gasket
Broken piston ring
Replace the head gasket or the piston
ring
2. GAS LEAKAGE NOISE
Ex
haust pipes Loosely connected exhaust pipes. Broken
exhaust pipes
Tighten the exhaust pipe connections
Replace the exhaust pipes
Inj
ection nozzles
and/or glow plugs
Loose injection nozzles and/or glow plugs Replace the washers
Tighten the injection nozzles and/or
the glow plugs
Ex
haust manifold Loosely connected exhaust manifold and/or
glow plugs
Tighten the exhaust manifold
connections
Cy
linder head gasket Damaged cylinder head gasket Replace the cylinder head gasket
3. CONTINUOUS NOISE
F
an belt Loose fan belt Readjust the fan belt tension
Cooling f
an Loose cooling fan Retighten the cooling fan
W
ater pump bearing Worn or damaged water pump bearing Replace the water pump bearing
G
enerator or vacuum
pump
Defective generator or vacuum pump Repair or replace the generator or the
vacuum pump
Valve c
learance Clearance improperly adjust Adjust the valve clearances

Isuzu 4JB1 Specifications

General

Brand	Isuzu
Model	4JB1
Category	Engine
Language	English