MAINTENANCE MANUAL OF ENGINE
137
3. Black smoke or grey smoke
The fuel injector or the injector nozzle
is damaged or blocked, resulting in poor
atomization and insufficient combus-
tion.
Repair or replace (Refer to Sec-
tion 6, Chapter 3 of this Part)
1. The fuel injection is too late, and par-
tial fuel is combusted in the exhaust
process.
2. The fuel supplied by the fuel injec-
tion pump is insufficient, causing une-
venness of the combustion power.
1. Adjust the fuel supply advance
angle to 16°±1° (Refer to Section
4, Chapter 3 of this Part)
2. Calibrate the pump (Refer to
Section 4, Chapter 3 of this Part)
1. The valve is not sealed tightly, re-
sulting in low compression ratio of cyl-
inders.
2. The valve is open slowly, and the
engine is operated roughly.
Grind the valve or adjust the valve
clearance (Refer to Section 1,
Chapter 3 of this Part)
The air filter is blocked, and the air in-
take quantity is insufficient.
Clean the air filter or change the
filter element.
Reduce the load within specified
range.
4. Insufficient compression pressure of cylinders
Intake and
exhaust
valves
The valves are not sealed tightly.
Grind the valve (Refer to Section
4, Chapter 1, Part II) or adjust the
valve clearance.
The valve spring is broken.
Replace (Refer to Section 3,
Chapter 6, Part II)
The valve clearance is inappropriate.
Adjust (Refer to Section 1, Chap-
ter 3 of this Part)
Carbon deposit, jamming or serious
wear of the piston ring
Clean the carbon deposit or re-
place it with new one (Refer to
Section 4, Chapter 2, Part II)
Cylinder head
Cylinder head
gasket
The cylinder head bolts are loosened or
the cylinder head gasket is damaged.
Tighten the bolts to 135-150N.m
or replace it with a new cylinder
head gasket.