check engine DATSUN PICK-UP 1977 Repair Manual

Notes

a

The
idle

rpm
and
CO

vary
accord

ing
to
the
altitude
Therefore

they

should
be

properly
adjusted
when

the

position
of
the
H
L
lever
is

changed

EF729

ADJUSTMENT

AND
INSPECTION

CARBURETOR
IDLE
R
P
M

AND
MIXTURE
RATIO

Cautions

3
On

automatic
transmission

equi

ped
models
check
should
be

per

formed
in

the
0

position

Be
sure
to

engage

parking
brake
and

to
lock
both
front
and

rear
wheels

with
wheel
chocks

b

Keep
your
foot
down
on
the
brake

pedal
while

depressing
the
accelera

tor

pedal
Otherwise
vehicle

surges

forward

dangerously

Notes

a
00
not

attempt
to
screw
the
idle

adjusting
screw
down

completely

Ooing
so
could
cause

damage
to

tip

which
in
turn
will
tend
to
cause

malfunctio11ll

b
If
idle
limiter

cap
obstructs

proper

adjustment
remove
it

To
install
idle
limiter

cap
refer
to

Idle
Limiter

Cap

c
After
idle

adjustment
has
been

made
shift
the
lever
to
the
N

or

P

position
for
automatic
trans

mission

d
When

measuring
CO

percentage
in
Engine
Fuel

b
Counties
1

219
m
4
000
ft
or

more
above
sea
level
have
been

designated
by
law
as

High
Altitude

Counties
For

further
details
refer

to
1977
OATSUN
PICK
UP
Service

Bulletin
Pub
No
257

0

I
Air
cleaner

rID
mOl

If
Low
altitude

Ll

n
n

L
n

Fig
EF
34

sert

probe
into
tail

pipe
more
than

40
em

15
7
in

CO
Idle

adjustment
with

CO
meter

Idle
mixture

adjustment
requires

the
use
of
a

CO
meter

especially
for

California
models
When

preparing
to

adjust
idle
mixture
it
is

essential
to

have

the
meter

thoroughly
warmed

up

and

calibrated

I

Check
carburetor

pipes
for

proper

connection

2
Warm

up

engine
until
water

tem

perature
indicator

points
to
the
middle

of

gauge
The

procedure
to
warm

up

engine
is
not

specifically
recom

mended
Either

driving
vehicle
or

oper

ating
engine
at

no
load
will

be

good

3
Make
sure
that
water

tempera

ture
indicator

points
to
the
middle

Further

keep

engine
running
at
about

2
000

rpm
for

about
5

minutes
with

out

applying
load
to

engine
in

order
to

stabilize

engine
condition

Engine

hood
should
be

open

4
Run

engine
for
about

10
minutes

at

idling
speed
Ouring
this
10

minutes

proceed
as
described
in

steps

5

to
9
below

5
Remove
air

hose
between
3

way

connector
5

way
connector
for
Cali

fornia
models
and
air

check
valve
as

EF
21
shown
in

Figure
EF
35

Plug
the
dis

connected
hose

to

prevent
dust

from

entering

0

o

EF259

Fig
EF
35
Disconnecting
air
hose

from
air
check
valve

6
Race

engine
I
500

to
2
000

rpm

two
or
three
times

under
no
load
then

run

engine
for
one
minute
at

idling

speed

7

Adjust
throttle

adjusting
screw

until

engine
is

at

specified
speed

Engine
speed

Manual
transmission

750

rpm

Automatic
transmission

in
0

position

650

rpm

8
Check

ignition
timing
If
neces

sary
adjust
it
to

specifications

This

operation
need
not
be
carried

out
at
1

600
Ian
1

000
miles
service

Ignition
timing

Manual
transmission

120
750
rpm
Non
California

100
750

rpm
California

Automatic
transmission

in
0

position

120

650

rpm

9
At

about
10
minutes

after

engine

is
run

at

idling
speed
adjust
idle

adjusting
screw
so

that
CO

percentage

is
at

specified
level

CO

percentage

Manual
transmission

2
t
l

at
750

rpm

Automatic

transmission

in
0

position

2
t
I
at
650

rpm

10

Repeat

procedures
as
described

in

steps
6

7
and
9
above

so
that
CO

percentage
is
at

specified
level
Check

ing
idle
CO
in

step
9
can

be
carried
out

right
after

step
7

II
Race

engine

1
500
to
2

000

rpm
two
or
three

iimes
under
no

load

and
make

sure
that

specified
CO

per

centage
is
obtained

12

Connect
air

hose
to
air

check

valve

If

engine
speed
increases

readjust
it

to

the

specified
speed
with
throttle

adjustingsqew

CO
idle
edJustment
without

CO
meter

If
CO

meter
is
not

available
the

following
procedures
may
be
used

L
Check

carburetor

pipes
for

proper

connection

2
Warm

up
engine
until
water

tem

perature
indicator

points
to
the

middle

of

gauge
The

procedure
to
warm

up

engine
is
not

specifically
recom

mended
Either

driving
vehicle
or

oper

ating
engine
at

no
load
will

be

good

3
Make

sure
that

water

temperature

indicator

points
to
the
middle

Further

keep
engine
running
at
about
2

000

rpm
for
about
5

minutes
without

applying
load
to

engine
in
order

to

stabilize

engine
condition

Engine

hood
should
be

open

4
Run

engine
for

about
10
minutes

at

idling

speed

During
this

10

minutes

proceed
as

described
in

steps

5
to

9
below

5

Remove
air

hose
between
3

way

connector
5

way
connector

for
Cali

fornia
models
and
air

check
valve

shown
in

Figure
EF

35

Plug
the
dis

connected
hose

19
prevent
dust
from

entering

6
Race

engine
1
500
to
2
000

rpm

two
or

three
times
under

no
load
then

run

engine
for

one
minute

at

idling

speed

7

Adjust
throttle

adjusting
screw
so

that

engine
speeds
are

as
indicated

below

Engine
speed

Manual
transmission

815

rpm

Automatic
transmission

in
D

position

670

rpm

8
Check

ignition
timing
if
neces

sary

adjust
it

to
the
value

required
by

specifications
This

operation
need

not

be
carried
out
at
1

600
km
1

000

miles
service

9
At
about

10
minutes
after

engine
Engine
Fuel

is

run
at

idling

speed
adjust
idle

adjusting
screw
until
maximum

rpm
is

obtained

10

Repeat
procedures
as
described

in

steps
6
7
and

9
above

until

engine

speed
at
best
idle
mixture
is
815

rpm

for

manual
transmission

models
and

670

rpm
for
automatic
transmission

models

in
D

position
Adjustment

in

step
9
can
be
carried
out

right
after

step
7

11
Turn
the

idle

adjusting
screw

clockwise
until

engine
speed
drops
off

below

specified

rpm

Engine
speed

drops
off

Manual
transmission

60
to
70

rpm

Automatic
transmission

in
D

position

15
to
25

rpm

12

Connect
air
hose

to
air

check

valve

If

engine
speed
increases

readjust
it

to
the

specified

speed
with

throttle

adjusting
screw

Idle
limiter

cep

Do
not

remove
this
idle

limiter

cap

unless

necessary
If
this
unit
is
re

moved
it
must

be

readjusted
at
lime

of

installation
To

adjust
proceed
as

follows

I

After

adjusting
throttle

or
idle

speed

adjusting
screw
check

to
be
sure

that
the
amount

of
CO
contained
in

exhaust

gases
meets

the
established

standard

2

Install
idle
limiter

cap
in

position

making
sure
that
the

adjusting
screw

can
rotate
another
1
8

turn
in

the

CO

RICH
direction

Carbo
to

per

CO

rich

450
lIS
rotation

t
CO
lean

J

SQ

dl
lim

ET031
1
e
Iter

cap

Fig
EF

36

Setting
idle
limiter

cap

FUEL

LEVEL

1

Turn

down
float

chamber
to
al

low
float
to

come
into

contact
with

needle

valve
and
measure

Hu
shown

EF
22
in

Figu
re
EF

37

When
H

is

approximalely
7

mill
0
283

in

lOp
float

position
is

correct

The

top
float

position
can

be
ad

justed
by

bending
float

seat

Upon
completion
of
the

adjust

ment

check
fuel
level
wi
th

attached

level

gauge

p

j

i

I

it

I
Float
seat

2

Float

3

Float
chamber

4
Needle
valve
t
I
IIf

ET032

Fig
EF
37

Adjusting
float
level

2

Adjust
bottom
float

position
so

that
clearance
h
between

float
seat

and
needle

valve
stemis
I

3
to
L
7

mm

0
051
to
0
067
in
when

Iloat
is

fully

rals
n

Jloa
t

goppe

q
re

3

After

adjustments
in

steps
I
and

2

above
have
been
made

make
sure

that

when
fuel
is

delivered
to
the
float

chamber

the
fuel
level
is
maintained

within
the

range
of23
mm

0
91
in

as

shown
in

FigureEF
38

H
23

mm
0
91
in

EF260

Fig
EF
38

Checking
ruellevel

FAST
IDLE

I
With

carburetor

assembly
reo

moved
from

engine
measure
throttle

valve

clearance
A

with
a

wire

gauge

placing
the

upper
side

of
fast

idling

screw
on
the
first

step
on
fast

idling

cam

EC527

Fig
EF
39
Mea

uring
throttle
valve

clearance

MfT

AfT

3
To

check
fast

idling
cam

setting

by
engine

speed
proceed
as
follows

Warm

up
engine
sufficiently
Set
Engine
Fuel

Fast

idling
earn

steps

o

04th

l

2nd

1st

EC528

Fig
EF
40
Fast

idling
cam

steps

2
The
clearance
should
be

specified

value
in

the

following
table
If
not
ad

just
the
clearance

by
turning
fast

idling
screw

Clearance
A
mm
in

1
33
to
I

47
0

0524
to
0

0579

1
58
to
1

72
0

0622
to
0

0677

fast

idling
cam
at
2nd

step
and
read

engine

speed
Fast

idling
cam
is

prop

erly
set
if

engine
speed
is
within

Engine
speed

rpm
Fast

idling
earn

MfT

AfT

VACUUM
BREAK

I

Close
choke
valve

completely

2
Hold
choke
valve

by
stretching
a

rubber
band
between
choke

piston

lever
and

stationary
part
of
carburetor

3

Grip
vacuum
break
rod
with

pliers
and

pull
straight
out

4
Under
this
condition

adjust
the

clearance
between
choke
valve
and

carburetor
body
B
in

Figure

EF
42
to

specified
value

by
bending

vacuum
brake
rod
I
900
to
2
800

2nd

step

2
200

to
3
200

S
B

j
CK
iXo

LL

r
I

il

L
J

1

Choke

piston
rod

2

Choke

spring

3
Choke

piston
EF516

4

Diaphragm
cover

5
Choke

piston
lever

6
Choke
valve

Fig
EF
42

Adjusting
vacuum
break

EF
23
Z

ET033
Fast

idling
carn

Nut

Fast

idling
screw

Choke
valve

Choke

connecting

rod

Throttle
valve

Fig
EF
41

Adjusting
the
clearance

of
throttle
valve

Fast

idling
earn

1st

step

specifications
below
Clearance
A
in

2nd

step
is

reference
value

Clearance
A

mm
in

0
94
to
1
18
0
0370
to
0
0465

L16
to
I
40
0
0457

to
0
0551

CHOKE
UNLOADER

Close
choke
valve

completely

2
Hold
choke
valve

by
stretching
a

rubber
band
between
choke

piston

lever
and

stationary
part
of
carburetor

3
Pull
throttle
lever
until
full

open

Under
this
condition

adjust
clear

ance
between
choke
valve
and
carbure

tor

body
to

2
45
mm
0
096
in

by

bending
unloader

tongue

Note
Make
sure
that
throttle
valve

opens
when
carburetor
is
mounted

on
the
vehicle

If
throttle
valve
rails
to

open
un

loader
becomes

inoperative
resulr

ing
in

poor
acceleration
after

engine

is
started

ELECTRIC
AUTOMATIC

CHOKE

Checklna
automatic
choke

heater
circuit
with
function

test
connector

Caution
Do
not
altach
test

leads
of

a

circuit
tester
to
those
other
than

designated
Refer
to

figure
Ef
43

I

With

engine
not
running
check

for

continuity
between
A

and
B

as

shown
in

figure
Ef
43

If

continuity
exists
heater
is
func

tioning
properly

If

continuity
d
s

not
exist
check

for
disconnected
connector

or

open

P
T

e
heater
circuit

2

With

engine
running
at
idle
check

for

presence
of

voltage
across
A
and
B

as
shown
in

figure
EF
43

If

voltmeter

reading
is
12
volts

d
c

heater
circuit
is

functioning

properly

If

vohmeter
reading
is
zero
check

for
disconnected
connector
open

circuit
or

faulty
automatic
choke

relay

3

Replace
faulty
parts

J
j

N

j

EF710
1

ignition
key

2
Automatic
choke

relay

Engine
stop
OFF

Engine
start
ON

3
Automatic

choke
heateI

4

Function
test
connector

5
Altema
tor

Fig
EF
43
Checking
oulomalic

choke
heater
circuit
with

fu
nc
non
led

connector
Engine
Fuel

Automatic
choke

I
Before

starting
engine
fully
de

press
al
celerator

pedaJ
to
ensure
that

choke
valve

doses

properly

Push

choke
valve
with
a

finger

and
heck
for

binding

3
Check
0
be
sure
that
bi

rnetal

cover
index

mark
is
set
at
the
cen
leT
of

choke

housing
index
mark
a
s
shown
in

Figure
EF
44

Note
Do
not
set
b
metal
cover
index

mark
at

any
position
except
the

center
of
choke

housing
index

marl

tE

jL

J

Thermostat
cover

Bi
metal

chamber

2
Thermostat

housing

3
Groove
ET034

Fig
EF

44
Bi

metol
tting

4

Check
automatic
choke
heater

source

wiring
for

proper
connection

then
start

engine

5

After

warming
up
the

engine
see

that

choke
valve
is

fully

open

6
If
automatic
choke
heater

source

wiring
is

normal
and
choke

valve
does

not

operate
after
warm

up
replace

hi

metal
co
t
er

Automatic

choke

relay

I
Remove
automatic
choke

relay

Auto
choke
heater

relay

EF278

Fig
EF
45
Location

of
automatic

choke

relay

EF
24
2

Make
an

operational
check
of

automatic
choke

relay
as
shown
in

Figure
EF
46

Apply
2

volts
d
c
across
termi

nals
I
and
3
to
ensure
that

i

ontinuity
exists
between
terminals

2
and
4

Check
t
lal

continuity
does
not

exist
between
terminals

2
and
4

when
no

voltage
is

applied
across

them
If
results
satisfies
the
above

automatic
choke

relay
is

functioning

properly
if
not

replace
choke

relay

1
2

3

y
4

EF723

Fig
EF
46

Checking
automatic
choke

relay

Automatic
choke
heater

I
Measure
resistance
of
choke

heater

as
shown
in

figure
EF
47

spe
ified
re
s

an
ce
is
3
7
to
8
9

ohms

F

EF261

Fig
EF
47
Automatic
choke
heater

check

2
If
measured
value
is

not
within

the

specification
replace
bi
metal

cover

INTERLOCK
OPENING
OF

PRIMARY
AND
SECONDARY

THROTnE
VALVE

Figure
EF
48
shows

primary
throt

tie
valve

opened
SO
When

primary

throtlle
valve
is

opened
50
the

adjust

plate
integrated
with
throttle
valve
is

in
contact
with
return

plate
at
A

When
throttle
valve
is

opened
fur

ther

locking
arm
is
detached
from

secondary
throttle
arm

permitting
see

ondary

system
to

start

operation

Linkage
between

primary
and

see

ondary
throttles
will
function

properly

if
distance

between
throttle
valve
and

inner
wall

of
throttle

chamber
is
74

mm

0
291
in

Adjustment
is
made

by
bending

connecting
link

I

L
l

1

4
CAl

Secondary
prm

ary
I

Jl
I

7
t
@

1
Roller

4

Adjust
plate

2

Connecting
lever

5
Throttle
c
amber

3
Return

plate
6
Throttle
valve

Fig
EF

48

Adjusting
interlock

opening

DASH
POT

1

Idling
speed
of

engine
and
mix

ture
must
be

well
tuned

up
and

engine
sufficiently
warm

2

Turn
throttle
valve

by
hand
and

read

engine
speed
when

dash

pot

just

touches

stopper
lever

3

Adjust
position
of

dash

pot
by

turning
nut

until

engine
speed
is
in
the

specified
range

Specified
engine

speed

Manual
transmission

1

900
to
2

100

rpm

Automatic
transmission

1
650
to
1

850

rpm

4

Tighten
lock

nuts

5
Make

sure
that

engine
speed

drops
smoothly
from
2

000
to
1

000

rpm
in

about
three

seconds
Engine
Fuel

Fig
EF
49

Adjusting
dash

pot

ACCELERATING
PUMP

I

Visually
inspect
accelerating

pump
cover
for

any
sign
of
fuel
leaks

2
If

fuel
leaks
are
found
check

gasket
and

replace
if

necessary

ANTI

DIESELING

SOLENOID
VALVE

If

engine
does
not

stop
when

igni

tion
switch
is
turned
off

this
indicates

that
a

striking
closed
solenoid

valve

is

shutting
off

supply
of
fuel
to

engine

If
harness
is
in

good
condition

replace
solencid
valve
as
a
unit

Notes

a

Tightening
torque
is
1

8
to
3
5

kg
m
13
to
25

ft
Ib

b

After

replacement
star

engine
and

check
to
be
sure
that
fuel
is
not

leaking
and
that
anti
dieseling

sol

noid
is
in

good
condition
B
C
D
D

CIRCUIT
WITH

FUNCTION
TEST

CONNECTOR

Caution
Do

not
attach
test
leads

of
a

circuit

tester
to
those
other

than

designated
Refer
to

Figure
EF

50

Menuel

trensmlsslon
models

I

Check
for

continuity
between
A

and
B
when

vehicle
is

brought
to
a

complete
stop
Refer
to

Figure
EF

50

B
C
D

D
circuit
is

functioning

properly
if

continuity
exists

and
volt

meter

reading
is

0
volt

d

c
in

step
2

below

If

continuity
does
not
exist

check

for

disconnected
connector
and
or

faulty
amplifier
speed
detecting

switch

or
B
C
D
D
solenoid
valve

2

Check
for

presence
of

voltage

across
A

and
B
at

a

speed
of
more

than
16

km
h

10
MPH
Refer
to

Figure
EF

50

Conduct
this

test

by
one
of
the

following
two

methods

I
Raising
up
rear
axle

housing
with

stand

2
Chassis

dynamometer
test

If
voltmeter

reading
is
0

volt
at
a

speed
of
more
than
16
km
h
10

MPH
circuit
is

functioning
prop

erly

If
voltmeter

reading
is
not
0
volt

check
for
disconnected
connector

burned
fuse

faulty
amplifier

B
C
D
D
solenoid
valve
or

speed

detecting
switch

3
If

by
above
checks

faulty
part
or

unit
is
located
it
should
be

removed

and
tested

again
If

necessary
replace

1

P4
11
0

8

l
1

Ignition
Icey

2

Fuse

3

Amplifier

4

Speed
detecting
switch

Above
10

mph
OFF

Below
10

mph
ON

5

Function
test
connector

6
B

C
D
D

solenoid
valve

EF711

Fig
EF

50

Checking
B
C
D
D
circuit
with

function
test

connector

for
manual
transmission

EF
25

AUtomatic

trailamlsalon
modela

I

With
inhibitor

switch
ON
UN

or
P

position
check
for

presence
of

voltage
across
A
and
B
Refer
to

Figure
EF
51

If
voltmeter

ading
is

12
volts

d
c
B
C
D
O
circuit
is

func

tioning
properly

If
vol
tmeter

ading
is

zero
check

for
disconnected

connector

faulty

solenoid
valve

m
inhibitor

switch

2
With
inhibitor

switch
OFF

HI
2
IY
or
oR

position
Engine
Fuel

check

for
resistance

between
A
and
B

Refer

to

Figure
EF
51

If

ohmmeter

reading
is
25

ohms
or

below
circuit
is

functioning
prop

erly

If

ohmmeter

reading
is
32

ohms
or

above

check
for

poor
connection

of
connec
or

faulty
B
C
D
D
sole

noid
valve
or
inhibitor

relay

3

If

by
above
checks

faulty
part
or

unit
is

located
it

should
be
moved

and

tested

again
If

necessary
replace

yu
@

@
1

Ignition
key

2

Inhibit
T
switch

N
P

positions
ON

I

2
D
R

positions
OFF

3
D

C
D

D
solenoid
valve

4

Function
test
connector

5

Inhibitor

relay

EF712

Fig
EF
51

Checking
B
C

D
D
circuit
with

unction
t
st
connector

for
automatic
transmi
sion

Set

pressure

of

Boost
Controlled

Deceleration
Device
B
C
D
O

Generally
it
is

unnecessary
to
ad

just
the

B
CD
D

however
if

it
should

become

necessary
to

adjust
it
the

procedure
is
3S
follows

Prepare
the

foUowing
tool

I

Tachometer
to

measure
the
en

gine
speed
while

idling
and
a

screw

driver

2
A

vacuum

gauge
and

connecting

pipe

Note
A

quick
response

type
hoost

gauge
such
as
Bourdon
s

type
is

recommended
a

mercury
type

manometer

should
not
be
used

To

properly
set
the

B
C
D

D
set

pressure
proceed
as
follows

I
Remove

the
harness
of
solenoid

valve
To
B
D
D

solenoid
valve

1

B
C
D
D

olenoid

valve

harness

EF262

Fig
EF
52

Removing
harness

of

solenoid
valve

2

Connect
rubber
hose
between

vacuum

gauge
and
intake
manifold

as

shown

Fig
EF
53

Connecting
vacuum

gauge

EF
26
3

Warm

up
the

engine
until
it
is

heated
to

operating
temperature

Then

adjust
the

engine
at
nunnal

idling
setting
Refer
to
the

item

Idling

Adjustmenl
in

page
EF

21

Idling

engine
speed

Manual
transmission

750

rpm

Automatic
transmission

in
D

position

650

rpm

4

Run
the

engine
under
no

load

Increase

engine
speed
to
3
000
to

3
500

rpm
then

quickly
close
throttle

valve

5
At
the
time
the
manifold
vacuum

p
ssure
increases

abruptly
to

600

mmHg
23

62

inHg
or
above

and

then

graduaUy
decreases
to
the
level

set
at

idling

6
Check
that
the
B
C
D
D
set

pres

sure
is
within
the

specified
pressure

Specified

pressure
0
m
sea
level

and

760

mmHg
30

inHg
atmos

pheric

pressu

Manual
transmission

510

to
550

mmHg

20
1

to

21
7

inHg

Automatic
transmission

490
to

530

mmHg

19Tto
20

9

inHg

Notes

a
When

atmospheric
pressure
is

known

operating
pressure
will

be

found

by
tracing
the

arrow
line

A

See

Figure
EF
56

When
alti

tude
is
known

operating
pressure

will

be
found

by
tracing
the
arrow

line
B

See

Figu
EF
56

b

When

checking
the
set

pressu
of

B

CD
D
find
the

specified
set

pressu
in

Figure
EF

56
from
the

atmospheric
pressure
and
altitude

of

the

given
location

For

example
if

an
automatic
trans

mission
model
vehicle

is
located
at

an
altitude
of
1

000

m
3

280
ft

the

specified
set

p
ssu

for

B
C
D
D
is
445

mmHg
17

5

inHg

7
If
it
is

higher
than

the
set
level

turn
the

adjusting
screw
or
nut
until

correct

adjustment
is

made

Non
California
models

Adjusting
screw

Counterclockwise

California
models

Adjusting
nut

Clockwise

Non
California

models

1
2

1

Adjusting
screw
s

2

Cover
e

California
models

t

1

Adjusting
nut

2

Lock

spring

EC692

Fig
EF
54

Adjusting
et

pressure

vacuum

gauge

Intake

gjl

11
Road
test
CD

ET037
Engine
Fuel

Note
When

adjusting
B

C
D
D
for

California
models
turn

adjusting

nut
in

or
out
with
lock

spring
in

place
Always
set
lock

spring

prop

erly
to

prevent
changes
in
set

pres

sure

8
Race

the

engine
and

check
for

adjustment

9
If
it

is
lower
than
the
set
level

turn
the

adjusting
screw

or
nut

until

correct

adjustment
is

made

10
Race
the

engine
and

check
for

adjustment

If

engine
speed
cannot
be
decreased

to

idling
when

checking
B
C

D
D

set

pressure
proceed
as
follows

When

the

engine
speed
does
not

fall

to

idling

speed
it
is

necessary
to

reduce
the

negative
idling

pressure
of

the

manifold
to
lower
than
the

set

pressure
of
the
B
C
D
O
The

engine

speed
will

not

drop
to

idling
speed

when
the

negative
idling

pressure
is

higher
Ihan
the

sel

pressure
of
the

B
C
O

O

acuum

gauge

Intakema
M

V
9iI

21
Chas
amomeler
In
this

case
the

engine
must

be

labored

by
I
road

test
or

2
chassis

dynamometer
or
3

by
raising
up
rear

suspension
member
on

a
stand

accel

erating
the
vehicle
to
64
to

80

km
h

40
10
50

MPH
in

top

gear
manual

transmission
or
in

0

position
auto

matic

transmission
and
then

releasing

the

accelerator

pedal
and

letting
the

vehicle
decelerate

After

doing
this

check
whether

the
B
C
O
D
set

pres

sure
is
at

the

predetermined
value
or

not

Vacuum

gauge

n
i
Y

3
Raise

up
rear
axle

housing
by
stand

ET133

Fig
EF
55

Testing
sel

pre
ure

of
the
B
C
D

D

EF
27

300
n

o

o

B
C

D
D
solenoid

valve

I
Turn
on

engine
key
Do
not
start

engine

Ensure
that
solenoid
valve

clicks

when

intermittently
electrified
as

shown
in

Figure
EF
57
1

000
2
000
3

000
4
000
5
000

0
5
1

0
6
000
ft

Altitude

km

1
5
2

0

EF558

Fig
EF
56

Changes
in
set

pres
ure
versus

changes
in

atmospheric

pressure
and
altitude

EF262

Fig
EF
57

Checking
solenoid
valve

EF

28
3

If
a

dick
is
heard
solenoid
valve

is

normal

4
I
f

a
dick
is
not
heard
ar
all
check

for
continuity
with

a
circuit
tester

If

discontinuity
is
detected

replace
sole

noid
valve

Amplifier
Manual

transmIssIon

models

The

amplifier
is
installed
at

the
rear

of
the

speedometer
To
check

proceed

as
follows

I

Set
circuit
tester
in
d
c

ampere

range
IA
min

fuU
scale
connect
test

probes
of
tester

as
shown
in

Figure

EF
58

Do
not
confuse

positive
line
with

negative
line

2
Turn

ignition
key
to

ON

posi

tion

I

t

EF264

1

Ignition
key

2

Amplifier

3

Speed
detecting
switch

4
B
C
D
D
solenoid
valve

Inhibitor

switch

Automatic

transmission

models

Refer
to
the
AT
section

Inhibitor

relay

Automatic
transmission

models

Inhibitor

relay

EF724

Fig
EF
59
Location
of
inhibitor

relay

2
Make

an
inhibitor

relay
check
as

shown
in

Figure
EF
60

Apply
12
volts
d
c
across
termi

nals
1

and
4

to
ensure
that

continuity

exists
between
terminals
2
and
3

Check
that

continuity
does
not

exist
between
terminals
2
and
3
when

no
voltage
is

applied
across
them
Engine
Fuel

3

Ensure
that
tester

pointer
deflects

when

ignition
key
is
turned
on

4
If
tester

pointer
does
not

deflect

when
solenoid
valve
and

speed
detect

ing
switch
circuits
are

functioning

properly
amplifier
is

faulty

Fig
EF
58

Checking
amplifier

If
results
satisfy
the
above

inhi

bitor

relay
is

functioning

properly
if

not

replace
inhibitor

relay

it
@

j
l

j
4

L
I

44
11

oJ

EF287

Fig
EF

60
Checking
inhibitor

relay

ALTITUDE

COMPENSATOR

California
models

Make
sure

that
altitude
com

pensator
to
carburetor

hoses
are
con

nected

properly
and
that

they
are
not

cracked
and
obstructed

2
Check
that
altitude

compensator

is

properly
set

At
low
altitudes

At

high
altitudes

Notes

a
The
idle

Pm
and
CO

vary
accord

ing
to
the
altitude
Therefore

they

should
be

properly
adjusted
when

the

position
of
the
H
L
lever
is

changed
Close

Open

EF
29
b
Counties
1

219
m
4
000

ft
or

more
above
sea
level
have
been

designated
by
law
as

High
Altitude

Counties
For
further
details
refer

to

1977
DATSUN
PICK
UP
Service

BuUetin
Pub
No
257

Q0

1
v

EF733

Fig
EF
61

Checking
altitude

compensator

MAJOR
SERVICE

OPERATION

The

perfectly
adjusted
carburetor

delivers
the

proper
fuel

and
air
ratios

at
all

speeds
for
the

particular
engine

for
which
it

was

designed
By
com

pletely
disassembling
which
will
allow

deaning
of
all

parts
and

passages
the

carburetor
can
be

maintained
its

origi

nal
condition
and
will
continue

to

deliver
the

proper
ratios

To
maintain

accurate
carburetion

of

passages
and

discharge
holes

ex

treme
care
must
be
taken
in

cleaning

Use

only
carburetor
solvent
and

compressed
air

to
clean
all

passages

and

discharge
holes
Never
use
wire
or

other

pointed
instrument

to
clean
or

carburetor
calibration
will
be
affected

REMOVAL

Remove
carburetor
from

engine

taking
sufficient
care
to

the

following

Precautions

a
When

disconnecting
fuel
lines
do

not

spill
fuel
from
fuel

pipe

b
When

removing
carburetor
do
not

drop
any
nut

or
bolt
into
intake

manifold

c
Be
careful
not
to
bend
or
scratch

any
part

Engine
Fuel

Throttle
chamber

parts

I
Idle

limiter

cap

2
Idle

adjust
screw

3
Idle

adjust
screw

sprinl

4
Throttle

adjust
screw

5
Throttle

adjust
screw

sprini

6
Primary
and
secondary

throttle
valves

7

Nut

Notc

Do
not
remove
the

parlS

marked
with
an
asterisk

@ff

EF827

Fig
EF
66

Removing
throttle
chamlHr

parta

Assembly

To

assemble
reverse
the
disassem

bly

procedcre
taking
care
to
the

following

I

Thoroughly
wash

all
the

parts

before

assembling

2

Inspect
gaskets
to
see
if

they
appear
hard
or
brittle
or
if

edges
are

torn
or

distorted

If

any
of
such
undesirable
condi

tions
is

noted

they
must
be

replaced

3
Install

jet
and
air
bleed

having
the

same
size
number

as
that
of

original
one

4
After
reassembling
carburetor

check
each

rotating
portion
or
sliding

portion
for
smooth

operation

EF

33