gas type DATSUN PICK-UP 1977 User Guide

FLOAT
SYSTEM

There
IS

only
one

float
chamber

while
two
l

arburetor

systems
primary

Jnd

st
l

ondary
are

provided

Fuel
fed
from
the
fuel

pump
flows

through
the
filler
and
needle

valve
into

the
flo
t
chamber
A

constant
fuel

level

is
maintained

by
the
float
and

needle
valve

Because
of

the
inner
air

vent

type

of

the
float
chamber
ventilation
the

fuel

consumption
will
not

be
in

fluenced

by
some
dirt
accumulated
in

the
air

deaner

The
needle
valve

includes

special

hard
steel
ball

and
will
not

wear
for
all

its

considerably

long
use
Besides
the

inserrion

of
a

spring
wiU

prevent
the

flooding
at

rough
road

running

BOOST

CONTROLLED

DECELERATION
DEVICE

B
C
D
D

A

Boost
Controlled
Deceleration

Device
B

C
D

D
serves
to

reduce
the

hydrocarbons

He
emitted
from
en

gine
during
coasting

The

high
manifold
vacuum

during

coasting

prevents
the
mixture

from

complete
combustion

because
of
the

reduced
amount
of
mixture

per
cyl

inder

per
rotation

of

engine
with
the

result
that

a

large
amount
of

hydrocar

bons
is

emitted
into
tile

atmosphere

The
B

C
D
D
has
been

designed
to

correct

this

problem

It

opern
tes

as
follows

when
the

manifold

vacuum
exceeds
a

pre
Engine
Fuel

determined

value
the

B
C
D
D
intro

duces

an
additional
mixture

of

opti

mum
mixture
ratio
and

quantity
into

the

manifold

by

opening
a

separate

mixture

passage
in
the

carburetor

Complete
combustion

of
fuel
is
assist

ed

by
this
additional
mixture

and
the

amount

of
H
C

contained
in

exhaust

gases
is

dramatically
reduced

During
the

transition

period
from

coasting
to

idling
the
transmission

produces
a

signal
which
turns
on
the

vacuum
control

solenoid
valve
As
this

takes

place
the
valve
is

lifted
off
its

seat

opening
the

vacuum
chamber
to

the

atmosphere
The
mixture

control

valve
is
then

closed

returning
the

engine
to
the

predetermined
idling

speed

On
manual

transmission
models

this

system
consists

of
B
C
D
D

vacuo

urn
control

solenoid
valve

speed
de

tecting
switch
and

amplifier

On
automatic

transmission

models

it
consists

of
B
C
D
D

vacuum
con

trol

solenoid
valve

and

inhibitor

switch

B
C
D
D

operation

Diaphragm
I

Qj
monitors
the

mani

fold

vacuum
and

when
the

vacuum

exceeds
a

pre
fetermined
value
acts
so

as

to

open
the

vacuum
control
valve

@
This
causes

the
manifold

vacu
urn

to
be

introduced
into
the

second

vacuum
chamber
and

actuates
dia

phragm
ll@

When

diaphrngm
II

operates
the

mixture

control
valve

@
opens
the

passage
and
introduces
the
additional

mixture
into

the
manifold

EF

18
The
amount
of

the
mixture

is
con

trolled

by
the

servo
action

of
the

mixture
control

valve

CID
and

vacuum

control

valve

@
so

that

the
manifold

vacuum

may
be

kept
at
the

pre

determined

value

The
amount

of
mixture

depends

mainly

upon
the

coasting
air
bleed

II@
while
the
mixture
ratio

is
deter

mined

by
the

coasting
jet

@
and

coasting
air
bleed

@
See

Figure

EF
31

Vacuum

control
solenoid

valve

operation

Manual

transmission
models

The

vacuum
control

solenoid
valve

is

con
troDed

by
a

speed

detecting

switch
that
is

actuated

by
the

speed

ometer
needle

As
the
vehicle

speed
falls

below
10

MPH
this
switch
is
activated

pro

ducing
a

signal
This

signal
actuates
the

amplifier
to

open
the
vacuum
control

solenoid
valve

Automatic

transmission
models

When
the

shift
lever
is
in
N

or

P

position
the
inhibitor
switch

mounted
on
the
transmission

turns
on

to

open
the
vacuum

control
solenoid

valve

There
are
three

types
of
control

system
These
are

J

Closed

type
CIllnkcase
emission

control

system
Emission
Control

System

of

GENERAL

DESCRIPTION

2

Exhaust
emission

control

system

3

Evaporative
ell
lhsion

control

sys

tem

Pericxiic

inspection
and

required
seCV1Clng
of
these

systems
should
be

carried
out

to
reduce

harmful
emis

sions
to
a
minimum

CRANKCASE
EMISSION
CONTROL

SYSTEM

c

01

Lkf

If
1

TIL
II
tll

1

j

GUuuu
DESCRIPTION

This

system
returns

blow

by
gas
to

both
the
intake
manifold
and
carbure

tor
air

cleaner

The

positive
crankcase
ventilation

p
C
V

valve
is

provided
to
conduct

crankcase
blow
by

gas
to
the
intake

manifold

During

partial
throttle

operation
of

the

engine
the
intake
manifold
sucks

the
blow

by
gas
through
the
P
C
V

valve

Normally
the

capacity
of
the

valve

is

sufficient
to
handle

any
blow

by
and

a
small
amount
of

ventilating
air

4

c
Fresh
air

Blow
by

gas
The

ventilating
air

is
then

drawn

from

the
dust
side
of
the
cadlUretor

air
cleaner

tluough
the
tube

con

necting
carburetor
air
cleaner
to
rock

er
cover
into
the

crankcase

Under
full
tluottle

condition
the

manifold
vacuwn
is

insufficient
to

draw

the
blow

by
flow

tluough
the

valve
and
its

flow

goes
through
the

tube
connection
in
the

reverse
diree

tion

On
vehicles
with
an

excessively

high

blow

by
some
of
the
flow
will

go

through
the
tube

connection
to

carbu

retor
air
cleaner
under
all
conditions

1

Sealtypc
oil
level

gauge

2
Bame

plate

3
Flame
arrester

4
Filler

5
P
C
Y
valve

6
Steel
net

7
Bame

plate

EC716

Fig
EC

l
Crankcase
miaion
control

ay
tem

EC

2
INSPECTION

P
c
V
VALVE
AND

FILTER

Checking
P
C
V
valve
in

accord

ance

with
the

following
method

With

engine
running
at
idle

remove

the

ventilator
hose
from
P

C
V
valve

if
the

valve
is

working
a

hissing
noise

will
be
heard
as
air

passes

through
the

valve

and
a

strong
vacuwn
should
be

felt

immediately
when
a

fmger
is

placed
over
valve
inlet

Replace
P
C
V
valve
and

filter
in

accordance
with
the
maintenance

schedule

VENTILATION
HOSE

1

Check
hoses
and

hose
connec

tions
for
leaks

2
Disconnect
all
hoses

and
clean

with

compressed
air

If

any
hose
cannot
be
free
of

obstructions

replace

Ensure
that
flame
arrester

is

surely

inserted
in

hose
between
air
cleaner

and
rocker
cover

Minimizes
exhaust

gas
tempera

lure
rise

2
Minimizes

horsepower
losses
re

suiting
from
air

injection
into
the

exhaust

system

3
Protects

pump
from
excessive

back

pressure

The
air

pump
relief
valve
is
installed

as
shown
in

Figure
EC

20

The

secondary
air
is

discharged

from
the
air

pump
relief
valve

to
the

dust
side
of
the
carburetor
air
cleaner

To
carburetor

air
cleaner

Secondary

air

To
carburetor

air

cleaner

J
erCOndary

r

r

EC294

Fig
EC
20
Air

pump
relief
valve
Emission
Control

System

Emargency
air
retial
valve

E
A
R
Valve

California
models

The

emergency
air
relief
valve
con

trols
the

quantity
of
secondary
air

fed

from
the
air

pump
according
to

load

condition
and
it

discharges
the
see

ondary
air
into
the

atmosphere
to

prevent
overheating
of
the

catalytic

converter

The

emergency
air
relief
valve
con

sists
of
a

diaphragm
a

spring
and

a

valve
which
is

coupled
to

diaphragm

1

Diaphragm

2

Val

3

Spring

4

Diaphragm
chamber

EC536

Fig
EC

21

mergency
air

relief
valve

OPERATION

As
mentioned

previously
there

are

two

types
of
Air

Injection
Systems

A
I

S
a

non
California

type
and
a
California

type
The
California
stand

ard

type
includes
a

system
which

controls

injection
of

secondary
air

so

as
to
assure

proper
function
of
the

catalytic
converter
and
a

system

which
controls
the

supply
of
second

ary
air
to

prevent
abnormal

tempera

tUfe
rise
in
the

catalytic
converter

The
A
I
S
consists
of
the

following

systems

L
A

system
which
allows

injection

of

secondary
air
into
the
exhaust

port

2
A

system
which

bypasses
sec

ondary
air

from
the
air

pump
relief

valve

to
the

carburetor
air

cleaner

during

high
speed
engine
operation

3
A

system
which

supplies
air

from

the
carburetor
air
cleaner

to
the
intake

manifold

by
means
of
the
anti

backfire

valve
so
as
to

prevent
after
fire

during

deceleration

4
A

system
which

controls

injection

of
the

secondary
air

by
means
of
the

air

control
valve

so
as
to
maintain
the

catalytic
converter
at
an

optimum

temperature
level
under

lightly
loaded

condi
tions

Califomia

type
only

5
A

system
which
controls
the

sup

ply
of

secondary
air

through
the
emer

gency
air

relief
vilve

io
pfevent
ab

normal

temperature
rise
of
the

cataly

tic

converter

California

type
only

A
I

S

operation
is

as
follows

I

I

t

1
r

9

I
Air

pump
6

Check
valve

I
0
L
2
Air

pump
air
deaner
7
Air

gallery
pipe

3
Air

relief
valve
8
Injection
non
e

r
4
Air
cleaner
9

Exhaust
manifold

5

Carburetor
10

Anti
backflIe
valve

EC179

Fig
EC
22
Non

California
type
A
I
S

EC
12

Air

pump

I

Operate
engine
until
it
reaches

normal

operating
temperature

2

Inspect
all
hose
hose
connec

tions
and
air

gallery
for
leaks
and

correct
if

necessary
before

checking

air

injection

pump

3
Check
air

injection
pump
belt

tension
and

adjust
to

specifications
if

necessary

4

Disconnect
air
supply
hose
at

check
valve

5

Disconnect
vacuum
hose
from
the

air

control
valve
California

type

only

6
Insert

open
pipe
end
of
Air

Pump

Test

Gauge

Adapter
STl9870000
in

air

supply
hose

Clamp
hose

securely

to

adapter
to

prevent
it
from

blowing

out
Position

adapter
and
test

lli
uge
so

that
air
blast
emitted

through
drilled

pipe
plug
will
be

harmlessly

dissipated

7
Install

a
tachometer

on

engine

With

engine
speed
at
2

600

rpm
ob

serve

pressure
produced
at

test

gauge

Air

pressure
should
be
100

mmHg

3

94

inHg
or
more

8
If
air

pressure
does

not
meet

above

specifications
proceed
as
fol

lows

I

Repeat
2
and
3

above

2
Disconnect
air

supply
hose
at

anti
backfire
valve

Plug
air

hose

open

ing
and

screw
with
a

clamp
Repeat

pressure
test

3
With

engine

speed
at
1

500

rpm

close
hole
of
test

gauge
with

finger
If

a

leaking
sound

is
heard
or

leaking
air

is
felt

by
ftnger
at
relief

valve
relief

valve
is

malfunctioning
Relief
valve

should

be

replaced
or

repaired

4

If
air

injection
pump
does
not

meet
minimum

requirement
of

pres

sure
test
it

should
be

replaced

Control
valve

The

following
procedures
are
reo

commended
for

checking
and
or
as

certaining
that
the
various

components

of
the
exhaust
emission
con
Irol

system

are

operating

properly

The

engine
and
all

components

must

be
at
normal

operating
tempera

tures
when
the

tests
are

performed

Prior

to

performing
any
extensive

diag

nosis

of
the
exhaust
control

system
it
Emission
Control

System

must
be
determined
that

the

engine
as

a
unit
is

functioning
properly

Check
valva

Warm

up
engine
thoroughly

2

Disconnect
hose

leading
to
check

valve
from
air

hose
COJUlector

3

Check
hose

opening
for

any
indi

cation
of
exhaust

gas
leaks
Ifleaks
are

detected

replace
check
valve

4

Race
the

engine

lightly
at
about

2
000

cpm
and
then

return
it
to

idling
VisuaDy
check
the
hose
for

any

indication
of
exhaust

gas
leaks
before

the

engine
returns
to

idling

speed
If

leaks
are
detected

replace
check
valve

EC310

Fig
EC
43

Checking
check
valve

Air

pump
raIle
valve

After

completing
inspection
of
air

pump
check
air

pump
relief
valve
in

the

following
steps

J

Disconnect
hoses

leading
to
check

valve
and
air
control

valve
from
air

hose

connector
and

install
blind

cap

to
the

connector

2
With

engine
running
at

about

3
000

rpm
under
no
load

place
your

hand
on
the
air

outlet
of
air

pump

relief
valve
to
check
for

discharged
air

If
no
air

is
felt

replace
the
air

pump

relief

valve

EC311

Fig
EC
44

Checking
air

pump
relief

valve

EC

18
Air
control
valve

C
U
ornla
models

I
Warm

up
engine
thoroughly

2
Before

checking
air
control

valve

check
all
hoses

for
loose
connection

leaks
etc
and

repair
or

correct
if

necessary

3

With

engine
idling
disconnect
the

outlet
side
hose
of

the
air
control

valve
and

place

your
hand
on
the
air

hose
outlet
to
check
for
air
If
no
air
is

felt

replace
the
air

control
valve

4

Pull
vacuum
hose
off
from
air

con
trol
valve
If

discharge
of
air
from

air
hose

stops
the
air
con
trol
valve

is

normaL
If

discharge
is
still
felt

replace

the
valve

Plug
up
the

removed

vacuum
hose

to

stabilize

engine
running

EC312

Fig
EC
45

Checking
air
control
valve

Emarsancy
air
rella
valve

E
A
R
Valve

lCalHornla
models

L
Warm

up
engine
thoroughly

2

Before

checking
air

control
valve

check
all
hoses
for
loose
connection

leaks
etc
and

repair
or
correct
if

necessary

3
Race

engine
approximately

2
000

rpm
under
no
load
Place

your

hand
on
air

outlet
of
E

A
R
valve
to

check
for

presence
of

discharged
air
If

no
air

is
felt

E
A

R
valve
is
normal

4

Disconnect
vacuum
hose
from

B
A

R
valve
as
shown
in

Figure
EC

46

6

Thermal
vacuum
valve

Open

E
G
R
control
valve
Close

E
G
R
ON

operation

The
E
G
R
circuit
is

completed

only
when

engine
coolant

temperature
Emission
Control

System

I

I
Note
Vacuum
condition

EC793

Fig
EC
51
E
G
R
not
actuated

is
above
the

working
temperature
of

the

thermal
vacuum
valve
and
carbu
retor
suction
vacuum
is

large
enough

to

open
the
E
G
R

control
valve

Y
m
l

fj

t1f
1t
3
0

l

P
@
0
f
Y
f

1
i0
W
g

1
i3
iiA
d

m

E
N
ti

n
k

i

l
i
Throttle
valve

n

L
r

E

G
R

control
valve

Open

E
G
R
control
valva

The

E
G
R

control
valve
controls

the

quantity
of
exhaust

gas
to
be
led

to
the

intake
manifold

through
vertical

movement
of
the

taper
valve
connect

ed

to
the

diaphragm
to
which

vacuum
Thermal
vacuum

valve

Open

Note

iiiI
Vacuum
condition

EC794

Fig
EC
52
E
G
R
actuated

is

applied
in

response
to
the

opening

of
the
carburetor
throttle
valve
The

E
G
R
control
valve
is
installed
on
the

E
G
R

passage
through
a

gasket

E
G
R
con
trol
valve
construction

and

type
vary
with

transmission

type
and

car
destination
For
identification

purposes
the

part
number
is

stamped

on
the
recessed

portion
at
the

top
of

the
valve

The

construction
of
the
E
G
R

control
valve
is

shown
below

EC
21

7
After
the

specified
amount
of

refrigerant
has

been

charged
into

sys

tem
close
manifold

gauge
valves
Then

detach

charging
hoses
from
service

valves
of

system
Be
sure
to
install

valve

cap
to

service
valve

8

Confirm
that
there
are

no
leaks
in

system
by

checking
with
a
leak
detec

tor

Refer
to

Checking
for
Leaks

Note

Conducting
a
performance
test

prior
to

removing
manifold

gauge
is

a

good
sen
ice

operation
Refer
to

Performance

Test

CHECKING
FOR

LEAKS

Conduct
a

leak
test
whenever
leak

age
of
refrigerant
is

suspected
and

when

conducting
service

operations

which
are

accompanied
by
disassembly

Dr

loosening
of

connection
fittings
Air

Conditioning

Refrigerant
is
a

colorless
odorless

gas
and

leakage
from

system
is
diffi

cult
to
detect

Accordingly
the
use

of

a

leak
detector
facilitates

check
for

leaks

Two
methods
of

checking
are

available
one

employs
a
halide

leak

detector
which
burns

propane
gas
or

butane

gas
and
the
other

is
an
electric

type
leak

detector

HALIDE
LEAK
DETECTOR

Since
the

propane
leak
detector
and

butane
leak
detector

are
the

same
in

respect
to
their

operation
this

section

describes
the

operation
of
the

propane

leak
detector

The

copper
screen
is
heated

by
the

burning
of

propane
Refrigerant
gas

decomposes
to

color
the
flame
when

it

contacts
the
heated
screen
The

gas
to

be
checked
is
drawn
into

the

sampling

tube

and
sent
out
to
the
burner
A

refrigerant
leak
can

clearly
be
detected

by
variations
in
the
color
of
the
flame

Propane
type

NO
LEAK

SMALL

LEAK

LARGE
LEAK
Greenish

blue

Yellow

Purple
AC010
1

Copper
reaction

plate

2

Flame

adjusting
lines

3

Burner

4

Sampling
tube

5

Strainer

6

Gas
bomb

7
Flame

adjuster

Fig
A
C
25

Checking
for
leak

Butane

type

Pale
blue

Bright
blue

Vivid

green

AC
15
I

Discharge

refrigerant
in

one
or

two
seconds
to
ascertain

that

system

has
a

sufficient

pressure
needed
for

leak
detection

Charge
with
04

kg
I

lb
of

refrigerant
if

necessary

2

Light
leak
detector

Adjust
the

height
of

the
ilame
between

flame

adjusting
lines
at
the

top
and
bottom

of
combustion

tube
A

reaction

plate

will

immediately
become
red

hot

3

Place
the
end

of

sampling
tube

near
the

point
of
the

suspected
leak

in

system

Notes

a
Since

refrigerant
gas
is
heavier
than

air

small
leaks
can
b

easily
detect

ed

by

placing
sampling
tube
direct

ly
below
the
check

point

b
Suitable
ventilation
is

required
If

refrigerant

gas
is

mixed
with
the

surrounding
air
leak
detector
will

always
indicate
a

response
and

detection
of
the
actual
leak
will
be

difficult

c

Never
bold
leak
detector
at
an

angle

Cautions

a
Never

inhale
the
fumes

produced

by
combustion
of

refrigerant
gas

since

they
are
toxic

b
Never
use
halide
torch
in
a

place

where
combustible
or

explosive

gas

is

present

4
The

ilame
will
be
almost

colorless

when
there
is

no

refrigerant
gas
being

burned
When
there
is

a
small

refriger

ant

gas
leak
the
ilame

will
be

green
or

yellowgreen
When

refrigerant

gas
leak

age
is

large
the
ilame
will
be
brilliant

blue
or

purple
Since
the
color
of
the

ilame
will
be

yellow
when
dust
is

being
burned
Or
there
is

aging
scale
on

copper
reaction

plate
always
keep
the

strainer
of

sampling
tube
and
reaction

plate
clean

5

Major
check

points

I
Compressor

Compressor
shaft
seal

rotate
the

compressor
by
hand

Oil
filler

plug

Flexible
hose
connections

Rear
cover
and
side
cover

gaskets

Service
valve

2
Condenser

Condenser

pipe
fitting

Condenser
inlet
and
outlet

pipe

connections

I

INSPECTION

Check
for

gas
leakage
as
follows

I

Plug
high
and
low

pressure
joints

on

compressor
with
blind

caps

2

Connect

charging
hoses
in
lines

between
manifold

gauge
and

high
and

low

pressure
service
valves

Connect

refrigerant
can

to
middle

hose
of

manifold

gauge

3

Open
valve
of
can

tap
and

charge

refrigerant
Loosen
oil
filler

plug
at

side
of

compressor
to

purge
air
out
of

compressor

4
Turn
shaft
5

or
6

turns
Then

confirm
that

pressure
does

not

decrease
on

low

pressure
gauge
If

gauge
indicates
a

pressure
decrease

there
is
a
leak

Conduct
a
leak
test

Under
such
a

condition
remove
and

then

install

parts
again

CYLINDER
HEAD

AND
VALVES

Insufficient

refrigerant
compression

is

likely
to
be
caused

by

damaged
head

gasket
or

damaged
valves

Prior

to

servicing
the
head
and
valve

plate
both
service

valves
should
be

opened
to
free

any
gas

pressure
which

may
be
in

the

compressor

REMOVAL

I

Remove
the
bolts

from

flanged

type
service

valves

using
Torx
Driver

Bit

Note
The
direction
of

flanged
type

service
valves

should
be
noted
for

reinstallation

AC812

Fig
AC
66

Removing
service
valves

2
Remove
the

remaining
bolts
in

the
head
Air

Conditioning

AC813

Fig
A
C
6
7
Removing

cylinder
head

bolts

3
Remove

valve

plate
and
head

from

cylinder
by
prying
or

tapping

under
the
ears
which
extend
from

valve

plate

If
head
and
valve

plate
adhere
hold

head
and

tap
valve

plate
ears

away

from

head
with
a

soft
hammer

Note
Do

not
hit
or

tap
head
to

separate
head
and
valve

plate
be

3use

damage
to
head

may
result

Fig
AC
68
Removing
valve

plate

and
head

4
When

removing
the

gaskets
use
a

sharp
edged
knife

Notes

a
In

removing
head

gasket
be

very

careful
not
to

damage
machined

sealing
surface

b
Do

not
reuse

gaskets

AC815

Fig
A
C
69
Removing
gasket

AC37
INSTALLATION

Valves
and
valve

plates
are
furnish

ed

only
as
a

complete
assembly

I

Apply
a
thin

film
of
clean

refrig

eration

oil
on
area
of
crankcase
to
be

covered

by
cylinder
gasket

2
Place

cylinder
gasket
in

position

on

cylinder
so
dowel

pins
in
crankcase

go
through
dowel

pin
holes
in

cylinder

gasket

3

Apply
a
thin

film
of
clean

refrig

eration

oil
to

top
and
bottom
valve

plate
areas
to
be
covered

by
gaskets

AC816

Fig
A
C
70
Applying
clean

refrigeration
oil

4
Place
valve

plate
in

position
on

cylinder

gasket
so

discharge
valve
as

semblies
i

e
smaller
diameter
assem

blies
with
restrainer

over
valve
reed

are

facing
up
and

locating
dowel

pins

go
through
dowel

pin
holes
in
valve

plate

Fig
A
C
71
Placing
valve

plate