1973 DATSUN B110 fuel filter

EMISSION
CONTROL
AND
TUNE
UP

EMISSION
CONTROL
SYSTEM

AN
D

ENGINE
TUNE
UP

CONTENTS

BASIC
MECHANICAL
SYSTEM
ET

Checking
and

adjusting
dash

pot

Adjusting
intake
and
exhaust
valve
automatic
transmission
model

only
ET
9

clearances
ET
1

Checking
carburetor
return

spring
ET
9

Checking
and

adjustin9
drive
belt
ET
2

Checking
choke
mechanism
choke
valve

Retightening
cylinder
head
bolts
manifold
and

linkagel
ET
9

nuts
and
carburetor

securing
nuts
ET
2

Checking
anti

dieseling
solenoid
ET
9

Checking
engine
oil
ET
2

Replacing
fuel
filter
ET
10

Replacing
oil
filter
ET
3

Checking
fuel
lines
hoses

pipings

Changing
engine
coolant
L
L
C
ET
3
connections
etc
ET10

Checking
cooling
system
hoses
and
THROTTLE
OPENER

CONTROL
SYSTEM

ET
10

connections

ET
4
Checking
and

adjusting
throttle

opener
ET
13

Checking
vacuum

fittings
hoses
and
TRANSMISSION
CONTROLLED
VACUUM

connections

ET
4
ADVANCE
SYSTEM

ET
17

Checking
engine
compression
ET
4
Checking
electrical
advance
control

system
ET
19

Checking
exhaust
manifold
heat
control
AUTOMATIC
TEMPERATURE
CONTROL
AIR

valve

ET
5
CLEANER
A
T
C
AIR
CLEANER

ET
20

IGNITION
AND
FUEL
SYSTEM

ET
5
Replacing
carburetor
air
cleaner
filter

ET
20

Checking
battery
ET
5
Checking
hot
air
control
valve

ET
20

Checking
and

adjusting
ignition
timing

ET
5
CRANKCASE
EMISSION
CONTROL

Checking
or

replacing
distributor
breaker
SYSTEM

ET
22

point
condenser
and

spark
plugs
ET
6
Checking
or

replacing
PCV
valve

ET
23

Checking
distributor

ignition
wiring
and

Checking
ventilation
hoses

ET
23

ignition
coil

ET
7
EVAPORATIVE
EMISSION
CONTROL

Checking
distributor

cap
and
rotor

ET
7
SYSTEM
ET
23

Adjusting
carburetor
id
Ie

rpm
and

Checking
engine
compartment
hose

mixture
ratio

ET

8
connections
and
fuel

vapor
control
valves
ET
23

Checking
fuel
tank

vacuum
relief
valve

operation
ET
24

BASIC
MECHANICAL
SYSTEM
1
Start

engine
and
run
it

until
it
is
heated
to

operating

temperature
or
at
least
more
than
800C

I760F
of

engine
oil

temperature
then

stop
engine
Adjusting
intake
and
exhaust

valve
clearances

Valve
clearance

adjustment
should
be
made
while

engine
is

stationary

To

adjust
proceed
as
follows
2
Rotate
crankshaft
to

bring
No
1

cylinder
in

top
dead

center
on
its

compression
stroke

3

Remove
valve
rocker
cover

to

gain
access
to
valve

ET
1

ENGINE

Replacing
fuel
filter

Check
for
a

contamination
element
water
deposit
and

defection

Fig
ET
15
Fuel
strcrineT

All

engines
use
a

cartridge
type
strainer
If
it
is
found

to
be

defective

replace
as
an

assembly

Checking
fuel
lines

hoses

pipings
connections
etc

Check
fuel
lines
for
loose
connections
cracks
and

deterioration

Retighten
loose
connections
if

necessary

replace
any

damaged
or

defective

parts

THROTTLE
OPENER
CONTROL

SYSTEM

The
function
of
the
throttle

opener
is

to

open
the

throttle
valve
of
carburetor

slightly
in

vehicle
decelera

tion

During
deceleration
manifold
vacuum
rises

and
a

quantity
of
mixture
in
the

enigne
is

not
sufficient
so
that

a
normal
combustion
can
not
continue
and
a

great

amount
of
unburned
HC
is

emitted
The
carburetor

equipped
with
the
throttle

opener
supplies
the

engine

with
an

adequate
charge
of
combustible
mixture
to

keep
proper
combustion

during
deceleration

resulting
in
re

markable
reduction
of

He
emission

The

operation
of
the

throttle

opener
is
as
follows
A

schematic

drawing
of
the

system
is
shown
in

Figure

ET
16

At
the

moment
when
the
manifold

vacuum
increases

as

occurs

upon
deceleration
the

control
valve

opens
to

transfer
the
manifold

vacuum
to

the
servo

diaphragm

chamber
and
the
throttle
valve
of
the
carburetor

opens

slightly
As
the
vehicle

speed
decreases

above
16

km
h

10

MPH
for
manual
transmission

only
the
manifold

vacuum
lowers
to
the

predetermined
value
The
vacuum

control
valve

begins
to
close

gradually
keeping
the

manifold

vacuum
at
the

predetermined
constant
value

As
a

result
both
low
HC
emission
and
normal

engine

brake

during
deceleration
are

obtained

The

altitude
corrector
is

provided
with
a

slight
preload

to

compensate
the

variation
of
the

atmospheric
pressure

Vacuum

control
solenoid

The

purpose
of
this
control
is
to
return
the

speed
of

engine
to
the

prescribed
idling
positively
To
be

accurate
the

control

prevents
the
throttle

opener
from

taking
normal

operation
when
vehicle

speed
is
below

16

km
h

IO
MPH
for
manual
transmission

equipped

model
or
when
transmission
is

placed
in

N
or

P

position
for
automatic
transmission

equipped
model

Current
flows

through
the

solenoid
when
vehicle

speed

falls
below
16
km
h
10

MPH
on

manual
transmission

equipped
model
or
when
the
transmission
is

placed
in

N
or

P

position
on
automatic
transmission

equipped
model

As
this
takes

place
the
needle
valve
is
lifted
off
its
seat

directing
air
from
the
air
chamber
to
the
servo

diaphragm
This
releases
the

operation
of
the
throttle

opener

When

vehicle

speed
goes
over
16
km
h

IO
MPH
or

when
transmission

is

placed
in
a

position
other
than

N

or
P

position
the
solenoid
is

deenergized

allowing
the
throttle

opener
to
take
normal
action

to

reduce
He
emission
to
a
minimum

ET
10

ENGINE

Caution

lock
the
front

and
rear
wheels

by
fully

pulling
the

parking
brake
lever
before
con

ducting
this
test

Fig
ET
32

Checking
for
operation
of
vacuum

advance

system

If

any
objection
is

found

by
the
check

mentioned

above

either
of
the

following
defects

may
be
the

cause

Poor
connection
or

broken
harness
and
fuse

2
Air

leakage
resulting
from

poor
connection
of
vacu

um
tube

3
Incorrect

operation
of

Top
switch

4
Defective

operation
of
vacuum

cutting
valve
sole

naid

5
Incorrect

operation
of
thermo
switch

Testing
of

Top
switch

1
Make
sure
of
insulation
between
lead
wire

terminal

of
transmission
switch
and
switch

body

2

Disconnect
lead
wires
at
the
switch

and
connect

ohmmeter
to
tenninals

3
Ohmmeter

should
indicate

infmity
co
when
shift

lever

is
in

Top
gear
position
And
it
should
indicate

zero
at
other

gear
position
including
Neutral

posi

tion

4
If

it
does
not

work

properly
in

step
3

replace
the

switch
with
a
new
one

Testing
of
thermo
switch

I

MaJ
e

sure
of

insulation
between
lead
wire
terminal

of
thermo
switch
and
thetmo
switch

body

2

Disconnect
lead
wire

at
switch
and
connect
ohm

meter
to
terminals
Ohmmeter
should
indicate
zero
when

temperature

indicate
the

passenger
compartment
is
above
l30C

550F

4
If
it
does

not
work

properly
in

step
3

replace

thermo
switch
with
a
new

one

AUTOMATIC

TEMPERATURE

CONTROL
AIR
CLEANER

A
T
C
AIR

CLEANER

Replacing
carburetor
air
cleaner

filter

The

paper
element

viscous

type
has
been

specially

treated
to

eliminate
bother

of

cleaning
until

replacement

It

should
be

replaced
with
a

new
one
at

regular
intervals

or
more
often

according
to
the

operating
conditions

Checking
hot
air
control
valve

Inspection

Among
the

possible
troubles
of
this
device
the

most

liable
is
the

permanent
opening
of
valve

This
trouble
is
not

noticed
in
warm
weather
but
in

cold
weather

appears
as

poor

performance
of

engine

such

as

tardy
acceleration
hesitation
or

engine
stall
In

such

case
first

inspect
this

device
before

checking
the

carburetor

Another
trouble
which

might
be

expected
is
that
the

underhood
air
is

kept
closed

by
the
valve

regardless
of

the

temperature
of
suction
air
around
the

sensor
while

the

engine
is

running
This
ttOuble

appears
in
the

form

of

extremely
excessive
fuel

consumption
or
decrease
in

power

The

inspection
of
this
device

should
be

proceeded
as

follows

Fig
ET

33
Correct

position
of
hoses

ET
20

EMISSION
CONTROL
AND

TUNE
UP

CD

@

Fresh
air

Blow

by

gas

Air
used
in

filtering
oil
1
PCV
valve

2
Flame
arrester

3
Oil
filler

cap

4

Baffle

plate
and

steel
net

E
C002

Fig
ET
J8
Crankcase
emission
control

system
at

full
throttle

open

Checking
and

replacing
PCV
valve

Test
PCV

valve
in
accordance
with
the

following

me
thod

With

engine
running
at
idle
remove
the
ventilator
hose

from
PCV

valve
If
the
valve
is

working
a

hissing
noise

will
be

heard
as
air

passes
through
the
valve
and

a

strong

vacuum
should
be
felt

immediately
when

a

finger
is

placed

over
the
valve
inlet
If
the
valve
is

plugged
replace
with

a

new
one
Check
for

deposit
plugging
in
the
hose
Clean
if

necessary

Intake
manifold

l

illlr
nnnl

UUUU
l
I

G

EC014

FigET
39
Cross
sectional
view

of
PCV
valve
Checking
ventilation
hoses

I
Check
hoses

and
hose
connections
for
leaks

2
Disconnect

all
hoses
and
blow
them

out
with

compressed
air

If

any
hose
can
not
be
free
of

obstructions

replace

with
a

new
one

Insure

that
the
flame
arrester
is

surely
inserted
in

the

hose

between
the
air
cleaner
and
rocker

cover

EVAPORATIVE
EMISSION

CONTROL
SYSTEM

Checking
engine
compartment
hose

connections
and
fuel

vapor
control

valves

Checking
fuel
tank

vapor
liquid
separator
and

vapor

vent
line

I

Check
all
hoses
and
fuel
tank

ftIler

cap

2

Disconnect
the

vapor
vent
line

connecting
flow

guide
valve
to

vapor
liquid

separator

ET
23

ABNORMAL

COMBUSTION

backfire
afterflfe

run
on
etc

Improper
ignition
timing

Fuel

system
in
trouble

Defective

cylinder
head

etc

EXCESSIVE
OIL

CONSUMPTION

Oil

leakage

Excessive
oil

consumption
ENGINE

Improper
ignition
timing

Improper
heat

range
of

the

spark
plugs

Damaged
carburetor
or
manifold

gasket

backfire
afterflre

Defective
carburetor

jet

Improper
function
of
the
float

Uneven

idling

Improperly
adjusted
valve
clearance

Excess
carbon
in
the
combustion
chamber

Damaged
valve

spring
backfire
afterure

Loose
oil
drain

plug

Loose

or

damaged
oil

pan
gasket

Loose
or

damaged
chain
cover

gasket

Defective
oil
seals
in
front
and

rear
of
the

crankshaft

Loose
or

damaged
locker

cover
gasket

Improper
tightening
of
oil
filter

Loose
or

damaged
oil

pressure
switch

Worn

cylinder
and

piston

Improper
location
of
the

ring
split
or
reo

versed

assembly

ET
32
Adjust
the

ignition
timing

Use

specified
spark
plugs

Replace
them
with
new
ones

Disassemble
the
carburetor
and

check

it

Adjust
the
level
and

check
the
needle

valve

Adjust

Readjust

Remove
the

cylinder
head
and

remove

carbon

Replace
it
with

a
new
one

Tighten
it

Renew
the

gasket
or

tighten
it

Renew
the

gasket
or

tighten
it

Renew
the
oil

seals

Renew
the

gasket
or

tighten
it

Do
not

tighten
excessively

Renew
the

gasket
and

tighten
it
cor

rectly

Retighten
or
renew

the
oil

pressure

switch

Overhaul
the

cylinder
and
renew
the

piston

Reassemble
the

piston
rings
correctly

ENGINE

27
Install
the
oil

pump
with
oil
filter

28
Install
the

alternator
fan
and

fan
belt

29
Install
the

fuel

pump

30

Install
the
distributor

assembly

Fig
EM
B7

Timing
maTk

Fig
EM
SS
Distributor
installation

EM
32
Notes
3
Set
the

No
1

piston
to
its

top
dead
center
of

the

compression
stroke

b
Before
installation
return

the
distributor
rotor

approximately
60

degrees
from

its

regular
posi

tion
Insert
the

assembly

meshing
the
distributor

drive

gear
and
driven

gear

After

installation
the
distributor
rotor
should

come

into
contact

with
the
mark
on
the
rotor

cap

fitting
as

shown
in
the

Figure

31

Install
the

spark
plugs
and

connect
the

distributor

to

plug
high
tension

lead
wire

32
Install
the
fuel
hoses

and
tubes

33
Install
the
clutch

cover

assembly

34
Install
the

engine
stingers
and

crankcase
ventilation

hose

35
Dismount

the

engine
from
the

working
stand

Install
the

engine
mountings

Water

pump

knocking

II
Other
mechanical

trouble

Sticked

valve

Seized

valve

seat

Excessively
worn

cylinder
and

piston
ENGINE

MECHANICAL

Improper
shaft
end

play

Broken

impeller

Improper
valve
clearance

Insufficient
clearance
between

valve
stem

and

guide

Weakened
or
broken
valve

spring

Biting
or

damage
ofvalve

stem

Poor
fuel

quality

Improper
valve

clearance

Weakened
valve

spring

Thin

valve
head

edge

Narrow
valve
seat

Overheat

Over

speeding

Sticked

valve

guide

Shortage
of

engine
oil

Dirty

engine
oil

Poor

oil

quality

Overheat

Wrong
assembly
of

piston
with

connecting
rod

Improper
piston
ring
clearance

Dirty
air

cleaner

Too

rich
mixture

Engine
over
run

Slicked
cho
e
valve

Over

choking

EM
39
Replace

Replace

Adjust

Clean
stem
or

ream
the

guide

Replace

Replace
or
clean

Use

good
fuel

Adjust

Replace

Replace
valve

Reface

Repair
or

replace

Drive
under

proper
speed

Repair

Add
or

replace
oil

Check
oil
level

on

daily
basis

Clean
crankcase

replace
oil

and

re

place
oil
fIlter
element

use

right
oil

Repair
or

replace

Repair
or

replace

Adjust

Clean

periodically

Adjust

Drive

correctly

Clean
and

adjust

Start
in

correct

way

ENGINE

6

f

I

Filter

to

Primary
main
nozzk
18

Secondary
throttle
valve

2
Needle
valve
11

Primary
main
air
bleed

19

Primal
throttle
valve

3

Secondary
slow

jet
12

Primary
slow
air
bleed
20
Idle
nozzle

4

Secondary
slow
air
bleed
13

Primary
slow

jet
2t

By
pass
hole

5

Secondary
main
air
bleed
14
Float
22

Primary
main

jet

6

Secondary
main
nozzle
15

Secondary
emulsion
tube
23

Primary
emulsion
tube

7

Secondary
air

vent

pipe
t6
Secondary
main

jet
24

Power
valve

8
Choke
valve
t7

Auxiliary
alve
25
Level

gauge

9

Primary
air
nt

pipe

Fig
EF
15
Sectional
view

of
model
DCH306
carburetor

bleed
The

gas
mixture
is

injected
into
the
venturi

through
the
main
nozzle

When
the

throttle
valve
is
wide

open
and
the

engine

requires
dense
mixture

gas
the

power
valve

opens

from
where
the
fuel
also
flows
into
the
main

system
Primary
system

Primary
main

system

The
fuel

flowing
out
of
the

passages
at
the

bottom
of

the

float
chamber

passes
through
the

primary
main

jet

and
is
mixed
with

the
air

coming
from
the
main
air

Secondary
side

Primary
side

1

Primary
main
nozzle

2

Primary
main
air
bleed

3
Primary
slow
air
bleed

4

Primary
slow

jet

5
Secondary
throttle
valve
6
Primary
throttle
valve

7
Idle
nozzle

8

By
pass
hole

9
Primary
main

jet

Fig
EF
16

PaTtially
loading

EF
10