FAILURE DIAGNOSTIC LIST
TNV DI Service Manual
1-223
Failure Diagnostic List
TNV DI Service Manual
FAILURE DIAGNOSTIC LIST
Failure Diagnostic List
Symptoms and conditions of failures
Cause
Defective start
Engine stall
after start
Defective rotation control
Insufficient
engine output
Noise/vibration
Lubricant
Cooling
water
Intake
Exhaust
Fuel
Electrics/electronics
Action
Referenced page number
Starter not
rotate
Starter
rotates
Exhaust
fume
Speed change
by accelerator n
ot ava
ilable (constant sp
eed)
Without load
At work
Exhaust color
Knocking noise at combustion to
o high
Combu
s
tion noise
uneven
Noise other t
han co
mbustion from engine
Engine vibration
too big
Lubricant consumptio
n too much
Lubricant dilu
ted with fuel
Lubricant mixe
d wit
h water
Oil pre
s
sure to
o low
(oil pressure lamp
on)
Overheated (water temperat
ure lamp on)
Water
temperature too low
Pressure dow
n (air cleaner lamp on)
Pr
essur
e
up
At work
Blow-by too much
Exhaust
temperatu
re up
Fu
el consumption too much
Fu
el mixed with water (oil
-water
separator lamp on
)
Fu
el filter contaminated too ea
rly
Battery charg
e defect (charge
lamp o
n)
ECU indica
tor lamp flashing
ECU indica
tor lamp not on just after key-on
(2 seco
nds)
Prescribed ECU control fun
c
tion not op
erate
Fu
se meltdown
, disconnection
(repe
ated)
ECU indica
tor lamp not on just after key-on
ECU indica
tor lamp on just
after key-on (2 seconds)
Engine not start (not even initial comb
ustion)
Engine not start (st
all after serial combustion)
Engine starts la
ter then e
v
er
None
Little
Much
Specified speed setti
ng not available
Poor acceleration
Return to low speed not
smooth
Hunting
Hunting
Nor
m
al
White
Blac
k
White exh
aust color
Black exhaust color
Engine syste
m
Intake/exhaust valve clearance
incorrect
c
c
c
c
c
c
Valve clearance adjustment
See "Measuring and Adjusting Valve
Clearance" (on page 6-66)
Compression failure at valve seat
c
c
c
c
c
c
c
c
c
Valve seat facing
See "Valve Face and Valve Seat" (on
page 6-43) for 2-valve head, and "Valve
Face and Valve Seat" (on page 6-59) for
4-valve head.
Intake/exhaust valve seizure
c
c
c
c
c
c
c
c
c
c
c
Correction or replacement of
intake/exhaust valve
See "Removal of Intake / Exhaust Valves"
(on page 6-39).
Cylinder head gasket blow-out
c
c
c
Gasket replacement
See "Removal of Cylinder Head" (on
page 6-54).
Piston ring sticking or breakage
c
c
c
c
c
c
c
c
c
c
c
c
Piston ring replacement
See "Reassembly of Pistons" (on page 6-
89).
Wear of piston ring, piston or cylinder
c
c
c
c
c
c
c
Horning work and usage of over-sized
parts
See "Honing and Boring" (on page 6-88).
Seizure of crank pin metal or bearing parts
c
c
c
c
c
c
c
Repair or replacement
See "Inspection of Crankshaft" (on page
6-86).
Closed gap position fault of piston ring
c
c
c
c
Correction of closed gap position
See "Reassembly of Pistons" (on page 6-
89).
Reverse assembling of piston ring
c
c
c
c
Correction of assembling
See "Reassembly of Pistons" (on page 6-
89).
Wear of crank pin metal and journal
metal
c
c
c
c
c
c
Measurement and replacement
See "Inspection of Crankshaft" (on page
6-86).
Connecting rod bolt loose
c
c
c
Tightening at specified torque
See"Torque for Bolts and Nuts" (on page
6-25).
Foreign material entered into
combustion chamber
c
c
c
c
Disassembling and repair
See "Disassembly of Engine" (on page 6-
72).
Gear backlash too big
c
Gear mesh adjustment
See "Checking Timing Gear Backlash"
(on page 6-73).
Wear of intake/exhaust valve guide
c
c
c
Measurement and replacement
See "Inspection of Valve Guides" (on
page 6-41).
Governor misalignment
c
c
c
c
c
c
Adjustment
Open/close timing failure of
intake/exhaust valve
c
c
c
c
c
c
Valve clearance adjustment
See "Measuring and Adjusting Valve
Clearance" (on page 6-66).
Engine vibration isolating support
loose, damage
c
c
c
c
Repair or replacement of faulty parts
TNV_DI_SM_A4-Troubleshooting.book 223 ページ ２００７年１１月１５日 木曜日 午後５時２７分
