1977 DATSUN PICK-UP check engine

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

CLEANING
AND

INSPECTION

Dirt

gum
wuler
or
l
arbon
con

taminatiun
in

or
on
exterior

moving

parts
of
a

arburctor
arc
often

respon

sihk
for

unsatisfactory
performance

For
this

reason
efficient
carbutetioll

dcpends
upon
careful

cleaning
and

inspection
while

servicing

I

Blow
all

passages
and

castings

with

compressed
air

and
blow
off
all

parts
until

dry

Note
Do
not

pass
drills

or
wires

through
calibrated

jet
or

passaaa

as
this

may
enlarge
orirlce
and

seriously
affect
carburetor
calibrs

lion

2

Check
all

parts
for
wear
If
wear

is

noted
damaged

parts
must
be
re

placed
Note

especially
the

following
Engine
Fuel

I
Check
float
needle

and
seat
for

wear
If
wear
is

noted

assembly
must

be

replaced

2
Check
throule
and
choke
shaft

bores
in
throtlle
chamber
and
choice

chamber
for
wear
or

out
of
roundness

3
Inspect
idle

adjusting
needle
for

burrs
or

ridges
Such
a

condition
re

quires
replacemen
1

3

Inspect
gaskets
0
see
if

they

appear
hard
or
briUle
or

if

edges
are

torn
or
distorted
If

any
such
condi

tion
i
noted

they
must
be

replaced

4
Check
filter
screen
for
dirt
or
lint

Clean
and
if
screen
is
distorted
or

remain

plugged
replace

5
Check

linkage
for

operating

condition

6

Inspect
operation
of

accelerating

pump
Pour
f
el
into

jloat
chamber

and
make
throtlle
lever

operate
Check

condition
of
fuel

injection
from

the

EF
34
accelerating
nowe

7

Push
connecting
rod

of
dia

phragm
chamber
and
block

passage
of

vacuum
with

finger
When

connecting

rod
becomes
free
check
for

leakage
of

air

or

damage
to

diaphragm

Jets

Carburetor

performance
depends

on

jet
and
air
bleed
That
is

why

these

components
must
be

fabricated

with
utmost
care
To

clean
them

use

cleaning
solvent
and
blow
air

on
them

Larger
inner
numbers

tamped
on
the

jet
indicate

larger
diameters
Ac

cordingly
main
and

slow

jets
with

lalger
nUmbers

provide
richer
mixture

the
smaller
the
numbers
the
leaner
the

mixture
Conversely
the
main
and

slow
air
bleeds

through
which
air
to

passes
through
make
the
fueLleaner
if

they
bear

larger
numbers
the
smaller

the
numbers

the
richer

the
fuel

Engine
Fuel

toms
and

causes
of
carburetor
troubles

and

remedies
for
them

are
listed
to

facilitate

quick
repairs

There
are
various
causes
of

engine

malfunctions
It
sometimes

happens

that
a
carburetor
which
has
no
fault
TROUBLE

DIAGNOSES
AND

CORRECTIONS

In
the

following
table
the

syml

Condition

Probable
cause

Overflow
Dirt
accumulated
on

needle
valve

Fuel

pump
pressure
too

high

Needle
valve

improperly
seated

Excessive
fuel

consumption
Fuel
overflow

Slow

jet
too

large
on
each
main

jet

Main
air
bleed

clogged

Choke
valve
does
not

open

fully

Outlet
valve
seat
of
accelerator

pump

improper

Linked

opening
of

secondary
throttle
valve

opens
too

early

Power

shortage
Main

jets
clogged

Every
throttle
valve
does
not

open
fully

Idling

adjustment
incorrect

FIICI
tr

clogged

Vacuum

jet

clogged

Air

c1eane

clogged

Diaphragm
damaged

Power
valve

operating
improperly

Altitude

compensator
setting
incorrect
Cali

fornia

models

Improper
idling
Slow

jet
clogged

Every
throttle

valve
does
not
close

Secondary
throttle
valve

operating
im

properly

Throttle
valve

shafts
worn

Packing
between

manifold
carburetor

fauJiy

Manifold
carburetor

tightening
improper

Fuel
overflow

B

C
D
D

adjustment
incorrect

Vacuum
control
solenoid

damaged

Stuck
anti
stall
dash

pot

EF

36
appears
to
have

some

problems
when

actually
the

electric

system
is
at
fault

Therefore
whenever

the

engine
is

mal

functioning
the
electrical

system

should
be
checked
rust
before

adjust

ing
carburetor

Corrective
action

Clean
needle
valve

Repair
pump

Re

place

See
condition
overflow

Replace

Clean

Adjust

Lap

Adjust

Clean

Adjust

AdjusL

pa
ir

Clean

Clean

Replace

Adjust

Correct
H
L
lever

position

Clean

Adjust

Overhaul
and

clean

Replace

Replace
packing

Correct

tightening

See
l
ondition
ov

rl1ow

Adjust

Replace

Replace