1977 DATSUN PICK-UP fuel

Engine
Mechanical

TROUBLE
DIAGNOSES
AND

CORRECTIONS

Condition

I

Noisy
engine

Knocking
of
crankshaft

and
bearing

Knocking
of

piston

and

connecting
rod

Camshaft

knocking

Timing
chain
noise

Camshaft
and
valve

mechanism

knocking

Water

pump
knocking
Probable
cause

Loose
main

bearing

Seized
bearing

Bent
crankshaft

Uneven
wear

of

journal

Excessive
crankshaft
end

play

Loose
bearing

Seized

bearing

Loose

piston
pin

Loose

piston
in

cylinder

Broken

piston
ring

Improper
connecting
rod

alignment

Loose

bearing

Excessive
axial

play

Rough
gear
teeth

Broken
eam

gear

Improper
chain
tension

Worn
and
or

damaged
chain

Worn

sprocket

Worn
and
or

broken
tension

adjusting

mechanism

Excessive
camshaft
and

bearing
clearance

Improper
valve
clearance

Worn

adjusting
screw

Worn
rocker
face

Loose
valve
stem

i1
1
guide

Weakened
valve

spring

Seized
valve

Improper
shaft
end

play

Broken

impeller

II
Other
mechanical
troubles

Stuck
valve

Improper
valve
clearance

Insufficient
clearance
between
valve
stem

and

guide

Weakened
or

broken
valve

spring

Biting
or

damage
of
valve
stem

Poor

Quality
of
fuel

EM
31
Corrective
action

Replace

Replace

Repair
or

replace

Correct

Replace
cen
ter

bearing

Replace

Replace

Replace
pin
or

bushing

Recondition

cylinder

Replace

Realign

Replace

Replace
bearing
thrust

plate

Repair

Replace

Adjust

Replace

Replace

Replace

Replace

Adjust

Replace

Replace

Replace
guide

Replace

Repair
or

replace

Replace

Replace

Adjust

Clean
stem
or
ream
guide

Replace

Replace
or
clean

Use
ood
fuel

DATSUN
PICK
UP

MODEL
620
SERIES

l
NISSAN

I

NISSAN
MOTOR
CO
LTD

TOKYO
JAPAN
SECTION
EF

ENGINE

FUEL

AUTOMATIC
TEMPERATURE

CONTROL
A
T
C
l

AIR
CLEANER

IDLE
COMPENSATOR

FUEL
FILTER

MECHANICAL
FUEL
PUMP

ELECTRIC
FUEL
PUMP

CARBURETOR
H
2

H
7

H

8

H

9

H

ll

H
14

Engine
Fuel

AUTOMATIC

TEMPERATURE
CONTROL
A
T

C

AIR

CLEANER

DESCRIPTION

OPERATION

A
T
C

AIR
CLEANER

HOT
AIR

OPERATION

A
T
C
AIR
CLEANER
COLD
AIR

OPERATION

A
T
C
AIR
CLEANER
COLD
AND

HOT

AIR
OPERATION

TEMPERATURE
SENSOR

DESCRIPTION

The
air

cleaner
removes
dust
and

dirt
from
the

air
before

it
enters
the

carburetor
and

engine
It
also

muffles

noise

resulting
from
the
intake

of
air

into
the

engine

The
air

cleaner

especially
designed

for

improved
exhaust
emission

control

is
referred
to

as
Automatic

Tempera

ture
Control

Air
Cleaner
In
order
to

reduce
HC
emission

when
the

under

hood

temperature
is

below
300C

860F
the

automatic

temperature

control

system
maintains
the

tempera

ture
of
air
to

be
sucked
in
the

carbure

tor
at
30

to
540C
86
to
1290F

thereby
enabling
lean

setting
for

carburetor

calibration
n

addition
to

this
the

automatic

temperature
con

twl

system
is

effective
to

improve

warm

up
characteristics
of
the

engine
CONTENTS

EF
2

EF
3
VACUUM

MOTOR
AND
AIR

CONTROL

VALVE

REMOVAL
AND

INSTALLATION

TEMPERATURE

SENSOR

VACUUM

MOTOR

FRESH

AIR

DUCT

AIR

CLEANER

INSPECTION

1
AIR

CLEANER
ELEMENT

2

HOT
AIR

CONTROL

SYSTEM
EF
3

EF
4

EF
4

EF
5

and
to

remove

carburetor

icing

The

A
T
C
air

cleaner

system
con

sists

of
the

following
devices

1
Air
cleaner

element

The
air

cleaner

element

employed
is

a

viscous

paper
type
It

requires
only

periodical
replacment
and
should
not

be

cleaned

2

Automatic

temperature
control

air

cleaner

In
the
A

T
C
air

cleaner
the
air

control
valve
is
actuated

by
intake

manifold

vacuum
to
control

the
intake

air
flow

circuit
The

temperature
sen

sor
detects
the

temperature
inside
the

air

cleaner
and

opens
or
closes
the

vacuum

passage

3

Hot
air
duct

The
hot
air
duct
is

mounted
on
the

exhaust
manifold
The
air
warmed

up

EF
2
EF
5

EF

5

EF

5

EF

5

EF
5

EF
6

EF
6

EF

6

EF

6

between
the

exhaust
manifold
and
hot

air
duct

is
led
to
the
air
cleaner

through
the

hose

4
Blow

by

gas
filter

The
blow

by

gas
nIter
removes
dirt

and
oil
from
the

blow

by
gas
sucked

in

the
air
cleaner
from
the

engine
rocker

cover

5

Fresh
air

duct

Except
for

Canada

The
fresh
air

duct
leads
the

outside

fresh
air

directly
to

the
air
cleaner

6
Idle

compensator

See

paragraph
Idle

Compensator

Page
EF
7

7

Altitude

compensator
California

models

See

paragraph
Altitude

Compensa

tor

Page
EF
20

Engine
Fuel

@

1

Fresh
air
duct

Except
for
Canada

2

Air
inlet

pipe

3
Vacuum
motor

assembly

4
Air
control
valve

5
Hot
air

pipe

6
Idle

compensator

7
Blow

by

gas
fiI
teT

8

Temperature
sensor
assembly

9
Altitude

compensator

California
models

EF713

Fig
EF
1
Automatic

temperature
control
air
cleaner

OPERATION

The
automatic

temperature
control

system
of
the
air

cleaner
is

controlled

by
the

inlet
air

temperature
and
the
load
condition
of
the

engine
The
inlet

air

temperature
is
detected

by
the

sensor
and
the
vacuum
motor
is
actu
ated

by
the

engine
intake
vacuum

Under
hood
air
Sensor
vacuum
at
Air

control
valve

Sensor

operation

temperature
vacuum
motor
side

operation

Below
60

mmHg

Open
cold
air

Below
300C
2
36

inHg

860

F
Close

Above
210
mmHg

Close
hot
air

8
27

inHg

30

to

540C
Half

open

Open

86
to
1290

F
cold
air
hot
air

Above
55
oC

Open
cold
air

Open

1310F

A
T
C
AIR
CLEANER
HOT

AIR

OPERATION

When
the
under
hood

air

tempera

ture
is
low
the

sensor
air
bleed
valve

remains
in
the

closed

position
and

establishes
vacuum

passage
between
the
intake

manifold
and

vacuum

motor
With
this
condition
the
vacu

urn

at
the
intake
manifold
side
actu

ates
the
air

control
valve
attached
to
the

vacuum
motor

diaphragm
to
intro

duce
hot
air
into
the
air
cleaner

through
the
hot
air

duct
on
the

ex

haust
manifold

EF
3

Underhood
air

I

@
Dr

Underhood
air

I
Engine
Fuel

f
f
l

l

ID
s

6

Cif

Ittl
ID
Air
inlet

pipe

Air
con
trol
valve

Hot
air

pipe

Diaphragm

Vacuum
hose

Diaphragm
spring

Air
bleed
valve

closed

Temperature
sensor

assembly
Holair

EF114

Fig
EF
2
Hota
r

delivery
mode

During
cold

engine
operation

7

To
manifold
Small

vacuum

1
Air
inlet

pipe

2
Air
con
trol

valw

3
Hot
air

pipe

4

Diaphnp

S
V
leuum
hoses

6

Diaphragm
prinl

7
Air

bleed
valve

closed

II

Temperature
senSOr

assembly

EF20S

Fig
EF
3
Cold
air

delivery
mode

During
cold

engine
operation

f
1

J
liP

omanifold
2

@
Air
inlet

pipe

Air

control
valve

Hot
air

pipe

Diaphragm

Vacuum
hoses

Diaphragm
spring

Air
bleed
valve

fully
open

8

Temperature
sensor

assembly

EF715

Fig
EF
4
Cold
air

delivery
mode

During
hot

engine
operation

ID

@
f

fjr

R
lfl
ow

2

underh
r
5

rv

Itti
ID

Hot
air
Air
inlet

pipe

Air
control
valve

Hot
air

pipe

Diaphragm

Vacuum
hose

Diaphragm
spring

Air
bleed
valve

partially
opened

8

Temperature
sensor

assembly

EF716

Fig
EF
5

Regulating
air

delivery
mode

EF
4
A
T
C
AIR
CLEANER

COLD
AIR
OPERATION

I

When
under
hood
air

temperature

is
low

The
sensor
air
bleed

valve
remains

in

the
closed

position
and
vacuum

passage
is

established
between
the
in

take
manifold
and

the
vacuum
motor

and
the
intake
manifold

vacuum
is

applied
to
the

vacuum
motor
dia

phragm
When
the

vacuum
is

small
or

when
the

engine
is

operating
under

eavy

1004
the
air

control
valve

opens

widely

irrespective
of
the

temperature

around
the

sensor
to
introduce
the

under
hood
air

cold
air

for
increased

power
of
the

engine

2

When
under

hood
air

temperature

is

high

The

sensor
air

bleed
valve

opens

fully
to
shut
off

the
vacuum

passage

between

the
intake
manifold
and
the

vacuum
motor
Due
to
the
force
of
the

vacuum
motor

diaphragm
spring
the

air

control
valve

closes
the
hot
air

pipe

of
the
air

cleaner
and

introduces
the

under

hood
air

cold
air

A
T
C
AIR
CLEANER

COLD

AND
HOT

AIR
OPERATION

When
the
sensor
air

bleed
valve
is

partially
opened
opening
of

the
air

control
valve
varies

with
the
vacuum

of
the

intake
manifold
With
the
air

control
valve
half
open

the
cold
air

and
hot
air
are
sucked

together
and

mixed
for

controlling
of
the
air

tem

perature
of
the
air

to
be
introduced
to

the
air

cleaner

TEMPERATURE
SENSOR

The

temperature
sensor
is

attached

to
the

inside
of
the
air

cleaner
The

bimetal
built
in

the
sensor
detects
the

under

hood
air

temperature
and

opens

or

closes
the
vacuum

passage
in
the

sensor

The
construction
of
the

tempera

ture
sensor
is
shown
in

the

following

CD
V
00
@

I

I

@
j
I

I

1
Protector
cover

Screw

Adjusting
frame

Air

temperature
bi

metal

Rivet

Valve
seat
frame

Lower
frame

Air
bleed
valve

Gasket

Fig
EF

6

Temperature
senior
EF206

VACUUM
MOTOR
AND

AIR
CONTROL
VALVE

The
vacuum

pressure
which
varies

with

opening
of
the
carburetor
throt

tle
acts

upon
the
vacuum
motor

dia

phragm
The
valve

shaft
attached
to

the

diaphragm
is
then
moved

up
or

down
in

response
to
the
vacuum
on

the

diaphragm
This
movement
of

the

valve
shaft

actuates
the
air
control

valve
to

control
the

temperature
of
the

air
to

be
introduced
into

the
air

cleaner

pr
to

I

1
Valve

spring

00
2

Diaphragm

@
3
Retainer

E
F

207
4
Valve
shaft

Fig
EF
7
Vacuum
motor

REMOVAL
AND

INSTALLATION

TEMPERATURE
SENSOR

Removal

Using

pliers
flatten

clip
con
Engine
Fuel

neeting
vacuum
hose
to
sensor
vacuum

tube

I

Pipe

2
Calch

3
Fixed
with

adhesive

4
Hose

5

Tab

6

Clip

7
Gasket

EC019

Fig
EF
B
Removal

of
semor

2

Disconnect
hose
from

sensor

3

Take
off

clip
from
sensor
vacuum

tube
and
dismount
sensor

body
from

air
cleaner

Note
The

gasket
between

sensor
and

air
cleaner
is
bonded
to
the
air

cleaner
side
and
should
not
be

removed

Inatallatlon

Mount
sensor
on
the

specified

position

For

mounting
position
of
sensor

see
the

following

EF717

Fig
EF
9

lalling
se
or
2
Insert

clip
into
vacuum
tube

of

sensor
After

installing
each
vacuum

hose
secure
hose
with
the

clip

Note
Be
sure
to
install
vacuum
hose

correctly
Correct

position
is
R

H

side
to
Nissan
mark
at
the

top

face
of

sensor
for
intake
manifold

L
H
side
for
vacuum
motor

VACUUM
MOTOR

1

Remove
screws

securing
vacuum

motor
to
air
cleaner

2
Disconnect
valve
shaft
attached

to

vacuum
motor

diapluagm
from
air

control
valve

and
remove
cacuum

motor

assembly
from
air

cleaner

3
To
install
reverse
the
removal

procedure

FRESH
AIR
DUCT

I
Disconnect
fresh
air
duct
at
air

cleaner

2

Fresh
air

duct
is

provided
with

projections
on
its
air
inlet
side
end

Hold
fresh
air
duct
with
a
hand
and

carefully

pull
out
from
radiator
core

support
while

turning
it
in
either

direction

3
To

install
reverse
the
removal

procedure
Be
sure
to

insert

projec

lions
of
fresh
air
duct

securely
into

mounting
hole
in

radiator
core

sup

port

EF518

EF
5
Fresh
air
duct

Air
cleaner

Duct

mounting
hole

Radiator

Radiator
core

support

Fig
EF

I0
Removal

of
fresh
air
duct

r

AIR
CLEANER

1
Loosen

bolts

securing
air
cleaner

to
air
cleaner
bracket

2
Loosen
air

cleaner
lock
bolt
and

remove
air

cleaner
from
carburetor

Disconnect
the

following
hoses
when

dismounting
air

cleaner

Under
hood
air
inlet

hose

Hot
air
inlet

hose

Vacuum

hose
Sensor
to
intake

manifold

Vacuum
hose
Sensor
to
vacuum

motor

Vacuum
hose

Idle

compensator
to

intake
manifold

Hose
Air

pump
to
air
cleaner

Hose
AB
valve

to
air
cleaner

Hose
Carburetor
to
air

cleaner

Blow

by
hose
Air

cleaner
to

rocker

cover

Hose
Air

control
vaive
to
air

cleaner
California

models

only

3
To

install

reverse
the
removal

procedure

INSPECTION

1
AIR
CLEANER

ELEMENT

Viscous

paper
type
air
cleaner

ele

ment
does
not

require
any
cleaning

operation
until
it

is

replaced
periodi

cally
Brushing
or

blasting

operation

will
cause

clogging
and

result
in
enrich

ment

of
carburetor
mixture

and

should
never
be

conducted
For

reo

placement
interval
of
air

cleaner
ele

ment
refer
to
Maintenance
Sched

ule

2
HOT

AIR

CONTROL
SYSTEM

In

warm
weather
it
is

difficult
to

find

out
malfunction
of
hot
air
control

system
In

cold
wea
thee

however

malfunction
of
air
control
valve

due
to

disconnection
or

deterioration
of

vacu

um

hose
between
intake
manifold
and

vacuum
motor
and

insufficient
dura

bility
of
air
control
valve

will
cause

insufficient
automatic
control

opera

tion

for
intake
air
and

result
in

engine

disorder

including

I

Stall

or
hesitation
of

engine

oper

ation

2

Increase
in

fuel

consumption

3

uck
of

power
Engine
Fuel

These

phenomena
reveal
malfunc

tion
of
hot
air
control

system
If
these

phenomena
should
occur
check
hot

air
control

system
as

described
in
the

following
before

carrying
out

inspec

tion

of
carburetor

2
1
Vacuum

hose

Intake
manifold
to
3

way
connec

tor
3

way
connector
to

temperature

sensor
3

way
connector
to

idle
com

pensator
temperature
sensor
to
vacu

um

motor

I

Check
that

vacuum
hoses
are

se

curely
connected
in

correct

postion

2

Check
each
hose
for

cracks
or

distortion

hose

clip
for

condition

Note

Vacuum
hose

position
R
H

side
of
Nissan

mark
on
the

top
of

sensor
is
for

intake
manifold
L
U

side
of

the
mark

is
for

vacuum

motor

2
2
Vacuum

motor

I

With

engine
stopped
disconnect

fresh
air

duct

Place
a
mirror

at
the
end
of
air

cleaner
inlet

pipe
as
shown
and

check

to

see
if
air

con
trol
valve

is
in

correct

position

EF213

Fig
EF
11

Inspecting
valve

position

Air

control
valve
is
in

correct

posi

tion
if
its
under
hood
air

inlet
is

open

and
hot
air
inlet
is

closed
Check
air

control
valve

linkage
for

condition

2

Disconnect

vacuum
motor
inlet

vacuum
hose
and
connect

another

hose
to
the
inlet
to

apply
vacuum
to

vacuum
motor
Vacuum
can
be

ap

plied
by
breathing
in
the

hose
end

as

shown

Place
a
mirror

at
the

end
of
air

cleaner
inlet

pipe
and

check
to

see
if

air

control
valve

is
in
correct

position

EF
6
EF217

Fig
EF
12

Inspecting
valve

position

Correct

position
of
air

control
valve

is

the
reverse
of

paragraph
J
above
Air

control
valve
is
in
correct

position
if

under
hood
air
inlet
is

closed
and
hot

air

inlet
is

open

3
With

hot
air

inlet
in

open
posi

tion

as
described
in

paragraph
2

above

pinch
vacuum
hose
with

fingers

and
cut
off
air

from
vacuum
hose
In

this
condition
check
that
air

control

valve

maintains
the

condition
de

scribed
in

step
2

for
more
than
30

seconds
and
that
hot
air

inlet
is

open

If

diaphragm
spring
actuates
the
air

control
valve

by
its

spring
force
to

open
under
hood
air
inlet

within
30

seconds

replace
vacuum
motor
as
an

assembly
since
this

may
be

resulted

from

air
leak
at
vacuum
motor
dia

phragm

2
3
Temperature
ensor

Check

temperature
sensor
for
func

tion

by

proceeding
as
follows
Be

sure

to

keep
engine
cold
before

starting

test

I

With

engine
off

check
air

control

valve
for
condition
In

this
case
under

hood
air

inlet
is

open
Use
a
mirror

for

inspection
as
2
2
1

above

2

Start

engine
and

keep
idling

Immediately
after

engine
starting

check
air
control
valve
for

correct

position
as
described
above
In

this

case
correct

position
of

air
control

valve

is
the
reverse
of
2
2
I

under

hood
air

inlet
is

closed
and
hot

air

inlet
is

open

3
Check
that
air
control
valve

grad

ually
opens
to
under
hood
air

inlet

side
as

engine
warms

up
When
en

vironmental

temperature
around
tern

perature
sensor
is

low

spend
more

time

for

engine
warming
up
operation

to

facilitate
smooth

operation
of
air

control
valve

If
the
above
test
reveals

any
prob

lem

in
the

operation
of
air

control

valve

carry
out
the

following
test

4
Remove
air

cleaner
cover
Set

temperature
sensing
element
of
ther

mistor
or

thermometer
to
a

position

where

temperature
around
sensor
can

be

measured
In

this
case
fIx

wiring
of

thermistor
or

thermometer
on
the

bottom

surface
of
air

cleaner
with

adhesive

tape
in

such
a
manner
that

the

set

position
of

temperature
sensing

DESCRIPTION

OPERATION

DESCRIPTION

The
idle

compensator
is

basically
a

thermostatic
valve

which
functions
to

introduce
the
air

directly
from
the
air

cleaner
to
the

intake
manifold
to

compensate
for
abnormal
enrichment

of
mixture
in

high
idle

temperature

The
bi
metal

attached
to
the
idle

compensator
detects

the

temperature

of
intake
air
and

opens
or
closes
the

valve
Two

idle

compensators
having

different

temperature
characteristics

are

installed
one

opens
at
an
intake
air

temperature
of

60
to
700C
140
to

l580F

and
the
other
at
70

to
900C

158
to
1940F

OPERATION

The
construction
of
the
idle

com

pensator
is

shown
in
the

following
Engine
Fuel

element
will
not
be
affected

by
air

flow

Then
install
air
cleaner
cover

Fig
EF
13

Checking
temperature

sensor

IDLE
COMPENSATOR

CONTENTS
5

Carry
out
test
as
described
in

steps
I
2
and
3
above
When
air

control
valve

begins
to

open
to
under

hood
air
inlet
side
several
minutes

after

engine
starting
read
the

indica

tion

of
thermistor
or

thermometer
If

reading
falls
within
the

working
tern

perature

range
of

temperature
sensor

the
sensor
is

normal
If

reading
ex

ceeds
the

range

replace
the

sensor

with
new
one

Note
Before

replacing
temperature

sensor
check

idle

compensator
as

described
in

Idle

compensator

EF
7

EF
7
REMOVAL
AND
INSTALLATION

INSPECTION
EF

B

EF

8

q

EF222
1

Orifice

2
Bi
metal

3
Rubber
valve

Fig
EF

14
Structure

of
idle

compensator

Bi

metal
Intake
air

temperature

No

1
Below
600C
1400F

60
to
70
C

140
to
l580F

Above
700C

158
OF

Below
700C

1580F

70
to
900C

158
to
1940F

Above
900C
1940F
No
2

EF
7
The
idle

compensator

operates
in

response
to
the

under
hood
air

temper

ature

as
shown
below

Idle

compensator
operation

Fully
closed

Close
to

open

Fully

open

Fully
closed

Close
to

open

Fully

open