1973 DATSUN B110 check engine

ENGINE

Adjusting
carburetor
idle

rpm

mixture
ratio

Idle

mixture

adjustment

requires
the
use
of
a

CO

meter
When

preparing
to

adjust
idle

mixture
it
is

essential

to
have
the
meter

thoroughly
warmed

and

calibrated

Warm

up
the

engine

sufficiently

2
Continue

engine
operation
for
one

minute
under

idling
speed

3

Adjust
throttle

adjusting
screw
so

that

engine
speed

is
800

rpm
in
NO

position
for
automatic
transmission

4
Check

ignition
timing
if

necessary
adjust
it
to
the

specifications

Ignition
timing
SO

800

rpm

S

Adjust
idle

adjusting
screw
so
that

CO

percentage
is

1
5
t
O
S

6

Repeat
the

adjustments
as
described
in

steps
3

and

S

above
so
that

CO

percentage
is
I
i
t
O

S
at
800

rpm

Cautions

a
On
automatic
transmission

equipped

model
check
must
be
done
in
the

0

position
Be
sure
to

apply

parking
brake

and

to
lock
both
front

and
rear
wheels
with
wheel

chocks

b
Hold
brake

pedal
while

stepping
down
on

accelerator

pedal
Otherwise
car

will
rush
out

dangerously

7

On
automatic
transmission

equipped
model
make

sure
that
the

adjustment
has

been
made
with
the
selector

lever

in
N

position

And
then
check
the

specifications
with
the
lever

in

D

position
Insure
that
CO

percent
and
idle

speed
are

as

follows

Idle

rpm

CO

percentage

with
lever
in

D

position
6S0

I
S
t
O
S

If

necessary
adjust
by
progressively

turning
throttle

adjusting
screw
and
idle

adjusting
screw

until
correct

adjustments
are

made
Notes
a
Do
not

attempt
to

screw
down
the
idle

adjusting
screw

completely
to
avoid

damage
to

the

tip
which
will

tend
to
cause
malfunctions

b
After
idle

adjustment
has
been
made
shift

the

lever
to
N
or
p

position
for
automatic

transmission

c

Remove
wheel
chocks
before

starting
the

car

Throttle

adjusting

screw

Idle

adjust

ing
screw

3
Idle

limitter

cap

4

Stopper

Fig
ET
13
Throttle

adjusting
screw
and
idle

adjusting
screw

Idle
limiter

cap

Do
not

remove
this
idle

limiter

cap
unless

necessary

If
this
unit
is
removed
it
is

necessary
to
re

adjust
it

at

the

time
of

installation
To

adjust
proceed
as
follows

L
Make

sure
that

the

percentage
of
CO

contents

satisfies
the

specifications

2
Install

idle
limiter

cap
in

position
making
sure
that

the

adjusting
screw

can
further
turn
3
8

rotation
in
the

CO
RICH

direction

CARB
STOPPER

J

Z

3
8
ROTATION

0

IDLE
LIMITER
CAP

0
to
RICH

CO
LEAN

Fig
l
T
14

Setting
idle
limiter

cap

ET
8

EMISSION
CONTROL
AND

TUNE
UP

Checking
and

adjusting
dash

pot

automatic
transmission
model

only

Check

operation
of
dash

pot
It
should

not
be
cracked

or

bound
It

is
also
essential
to
check
to
be
certain

that
it

is
in

correct

adjustment

L
Check
to
be
sure
that
dash

pot
contacts

stopper
lever

when

engine
speed
reaches
1
900

to
2

000

rpm

2

Engine
should
be
slowed
down
from
3

000
to
1

000

rpm
within
a
few

seconds

Readjust
dash

pot
or

replace
it
with
a
new
one
if
it

fails

to
meet

the
above

conditions

Checking
carburetor
return

spring

Check
throttle
return

spring
for

sign
of

damage
wear

or

squareness
Discard

spring
if
found
with

any
of
above

excessively
beyond
use

Checking
choke
mechanism

choke
valve
and

linkage

1

Check
choke
valve
and

mechanism
for
free

operation

and
clean
or

replace
if

necessary

A

binding
condition

may
have

developed
from

petro

leum

gum
for
motion
on
choke
shaft
or

from

damage

2

Check
bimetal
cover

setting
position
The

index
mark

of
bimetal
cover
is

usually
aligned
at
the

middle

point
of

the
scale

Note
When
somewhat
over
choked
turn
bimetal

caver

clockwise

slightly

3
Prior
to

starting
check
to
be
sure
that

choke
valve

closes

automatically
when

pressing
down
on
accelerator

pedal

Should
it
fail
to
close

automatically
the
likelihood
is

that
fast
idle
cam
is
out
of

proper

adjustment
or

that

bimetal
is

not

properly
adjusted
calling
for

adjustment

Refer
to
Carburetor
in
Section
EF

Page
EF
15
Checking
anti

dieseling
solenoid

If

engine
will
not

stop
when

ignition
switch
is
turned

off

this
indicates

a

striking
closed
solenoid
valve

shutting
off

supply
of
fuel
to

engine
If
harness
is
in

good

condition

replace
solenoid
as
a
unit

To

replace
proceed
as
follows

Removal

and
installation

of
anti

dieseling
solenoid

Removal

Solenoid
is
cemented

at

factory
Use

special
tool

STl
91
50000
to
remove
a

solenoid

When

this
tool
is

not
effective
use
a

pair
of

pliers
to

loosen

body
out
of

position

lnstalltion

I
Before

installing
a
solenoid
it
is

essential
to
clean

all
threaded

parts
of
carburetor

and
solenoid

Supply

screws
in
holes
and
turn
them
in

two
or

three

pitches

2
First
without

disturbing
the
above

setting
coat
all

exposed
threads
with
adhensive
the

Stud
Lock
of

LOCTlTE
or

equivalent

Then

torque
screws
to
35
to
55

kg
cm
30

to
48
in

lb

using
a

special
tool
STl9150000

After

installing
anti

dieseling
solenoid
leave
the
carbu

retor
more
than
12

hours
without

operation

3

After

replacement
is
over
start

engine
and
check

to
be
sure
that
fuel
is
not

leaking
and
that
anti

dieseling
solenoid
is
in

good
condition

Notes
a
Do
not
allow
adhesive

getting
on
valve

Failure
to
follow
this
caution
would
result
in

improper
valve

performance
or
clogged
fuel

passage

b
I
n

installing
valve
use
caution
not
to
hold

body
directly
Instead

use

special
tool

tighten

ing
nuts
as

required

ET
9

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

EMISSION
CONTROL
AND

TUNE
UP

Operation
manual
transmission

equipped
model

The

operation
of
the
solenoid
is

by
means
of
the

movement
of

the

speedometer
needle

When
vehicle

speed
falls
below
16

km
h

10

MPH
the

needle
movement

produces
a

signal
which
in
turn
is

amplified
to
actuate
the

solenoid

I
Vehicle

speed
Speed
Throttle

Throttle

switch
opener

opener

solenoid

Below
16
km
h
Not

10
MPH
ON
ON

actuated

Above

16
km
h

OFF
OFF

Actuated

10
MPH

Operation
automatic
transmission

equipped
model

The

solenoid
is

operated
by
an
inhibitor

switch
which

actuates
the
solenoid

only
when
the
transmission
is

placed
in

the
N
or
P

position

c
fil

rn

AT057

Fig
ET
18

Inhibitor
switch
installation

Checking
and

adjusting
throttle

opener

Principally
it
is

unnecessary
to

adjust
the
throttle

opener
however
if
there
is

any
requirement
the

adjust

ment

procedure
is
as

follows

Prepare
the

following
tools

1
A

tachometer
to
measure
the

engine

speed
and
a

screwdriver

2
A
vacuum

gauge
and

connecting
hose

ET
13
Notes
a
A

quick

response
boost

gauge
such

as
Bour

don
s
tube

type
is
recommended
Do
not

use

mercury
manometer

b

Any
special
tools

are
not

required

Warming

up

Warm

up
engine
until
it
is
heated

to

operating

temperature
Make
sure
that

the
automatic
choke
valve

is

fully
open

Connecting
vacuum

gauge

Disconnect
vacuum
hose
between
intake

manifold
and

automatic

temperature
controlled
air

cleaner
install

a

vacuum

gauge
to
intake
manifold
connector
as
shown

in

Figure
ET

19

1
Intake
manifold

2
Connector

3
Vacuum

gauge
4
Vacuum
control
valve

5
Throttle

opener

solenoid

Fig
ET
19

Adjusting
throttle

opener

Deenergizing
solenoid

Disconnect
throttle

opener
and
vacuum

cutting
valve

solenoid
harness

and
free
solenoid

Adjusting
idling

Check
the

engine
idling
Adjust
if

necessary

Engine
idling

rpm
Idling

timing

I
CO

degree

SO

BTDC

I
L51c0
5

SO

BTDC

I
I
S
1c
0
5
M
T
Car

A
TCar
800

6S0
in
D

EMISSION
CONTROL
AND
TUNE
UP

The
thermo
switch
is
screwed
on
the

dash
side

panel

RH
The
bi
metallocated
in
the

thermo
switch

prevents

the
flow
of
electric

current
when
the

temperature
is

below

the

specifications
and

thus
ensures
a

proper
running

performance
immediately
after

starting
the

engine
in
cold

weather

A

Fig
ET
30
Thermo
switch
installation

A
view

I

llf

F

ID

1
Note
Operation
of
the
thermo
switch
is

hysteresis
of
the

bi
metal
It

opens
between
50C

410FI
and

130C

550
F
when

temperature
rises
from
low
to

high
It

closes
above
lOC

34
0
F
when

temperature
lows

from

high
to
low

An
orifice
is

employed
in
the

vacuum
hose

connecting

the
carburetor
and

tee
to
restrict
the
air
flow

by
passing

the
carburetor
when
the
needle
valve

opens
and
air
is

freely
introduced

through
the

vacuum
hose

1
Flow

guide
valve

2
Orifice

3
Vacuum

cutting

valve

solenoid

r

d

01
DATSUN

Fig
ET
31
Vacuum

tube

diagram

Checking
electrical
advance

control

system

Disengage
the

clutch
and
race
the

engine
at
normal

ambient

temperature
if
ambient

temperature
is
low

warm

up
the

engine
and

pull
off
the
vacuum
hose
from

the
distributor

Through
this

vacuum
hose

if
vacuum
is
felt
at
the

top
gear
position
and
is
not
felt
at
other

positions
it
is

satisfactory

It
is

correct
if
vacuum
is

always
felt
at
low

tempera

tures
below
l30C
550F

before
the

engine
is
warmed

up

ET
19

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

Appearance

1
First

inspect
whether
vacuum
hoses

are
connected

to
correct

positions

2

Inspect
hoses

for
cracks
distortion
or

plugging

Checking
of
vacuum
motor

I

With

engine
shut
down

inspect
the

position
of
valve

placing
a
mirror
at
the
end
of
inlet

pipe
for

inspec

tion

The
correct
condition
of
valve
is
that
it

keeps
the

inlet
of
underhood
air

open
and
that
of
hot
air

closed

Otherwise

inspect
the

linkage
of
valve

Fig
ET
34

Inspecting
valve

position

2
Disconnect
hose
at
vacuum

motor
inlet
and
direct

ly
apply
vacuum
of
manifold
to
vacuum
motor

by

connecting
another
hose

sucking
by
mouth

may
be

substituted
for
this

process
If
underhood
air
inlet
is

closed

by
valve
valve
is
in

good
condition

Inspect

linkage
if
found
otherwise
And
then
no

defect
is

found
even
in

linkage
it

signifies
the
trouble
of

vacuum
motor

Fig
ET
35

Checking
vacuum
motor

ET
21
3
The
valve

shows
correct
condition
if
it

keeps

underhood
air
inlet
closed
when
the

passage
in

the
hose

is

stopped
by
twisting
or

clamping
it
while

applying

vacuum
If
otherwise
it
is
an
indication
of

leakage

taking
place
in
the
vacuum
motor

4
When
defect
is
found

in
vacuum

motor

through
this

check
replace
the
air
cleaner

assembly

Checking
of
sensor

I
Perform
the

engine
test

by
keeping
the

temperature

around
the

sensor
below
300C
860F
Make

sure
that

the

engine
is
cooled
down

before
the
test
is
conducted

2
Before

starting
the

engine
make
certain
that
the

valve

on
underhood
air
side

fully
opens

3
Start
the

engine
and

operate
it

at
an

idling
speed

The
valve
is
in

good
condition

if
underhood
air
side

fully
closes

immediately
after

starting

4

Carefully
watch
the
valve

to
ascertain
that

it

gradually
begins
to

open
as
the

engine
warms

up
But

when
the
ambient

temperature
is
low
it
takes

con

siderable

length
of
time

for
the
valve
to

begine
to

open

or
in
some
case
it

hardly
opens
This
should

not

however
be

regarded
as
trouble

If
the
valve
does

not

operate
satisfactorily
or
if
the

condition
of
the
valve
is

questionable
further
conduct

the

following
test

5
Remove

the
air

cleaner
cover
and

put
a
thermister

or
a
small
thermometer
as
close
to
the

sensor
as

possible
with
adhesive

tape
Install
the

air
cleaner

cover

again

Fig
ET
36

Checking
sensor

1

ENGINE

6
Start
the

engine
and
continue

idling
as
described

under

paragraphs
I
2
and
3
above

When
several

minutes
have

passed
and

the
valve
is

partially
opened

read
the

thermister
indication
It
is
correct

if
the

reading
falls
between
380C
1000
F
and

550C

1300
F

If
the

reading
is
abnormal

replace
the
sensor

7

On
the

engine
equipped
with

an
idle

compensator
as

service

option
do
as
follows
before

replacing
the

sensor

Clog
hose
on
idle

compensator
side

by

twisting
or

clamping
it

and
check
the

temperature
as

given
in

paragraphs
5
and

6
above
If
the
thermometer

shO
vs

correct

temperature

replace
the
idle

compensa

tOf
if
the

reading
is
abnormal

replace
the
sensor

CRANKCASE

EMISSION
CONTROL

SYSTEM

This

system
returns
blow

by

gas
to
both
the

intake

manifold
and
carburetor

air
cleaner
The
Posirive
Crankcase
Ventilation

PCV
valve
is

provided
to
conduct
crankcase
blow

by

gas
to
the
intake

manifold

Duirng
partial
throttle

operation
of

the

enigne

the
intake

manifold

sucks
the

blow

by
gas
through
the

valve

Normally
the

capacity
of
the

valve
is
sufficient
to

handle

any
blow

by
and

a
small

amount
of

ventilating
air

The

ventilating
air

is
then

drawn
from

the
clean
side
of

the
carburetor
air

cleaner

through
the

tube

connecting

carburetor
air

cleaner
to
rocker
cover

intu
the
crankcase

Under
full

throttle
condition
the
manifold
vacuum
is

insufficient
to
draw

the
blow

by
flow

through
the
valve

and
its
flow

goes

through
the
tube

connection
in
the

reverse
direction

In
cars
with
an

excessively
high
blow

by

some
of

the
flow

will

go
through
the
tube

connection

to

the
carburetor
air

cleaner
under

all
conditions

j

Fresh
air

Blow

by

gas

1m
Air
used
in

filtering
oil
t

2

3

4
PCV
valve

Flame

arrester

Oil
filler

cap

Baffle

plate
and

steel

net

ECOOl

Fig
ET
3
7
Crankcase
emission
control

system
at

partially
throttle

open

ET
22