1977 DATSUN PICK-UP Service Manual

E
G
R
OFF

operation

When

engine
coolant

temperature

is
low

recirculated
exhaust

gas
causes

irregular
engine

operation
To

prevent
Emission
Control

System

this
recirculation

of
exhaust

gas
must

be
cut
off

for
a
few

minutes
after

engine
has
started
The
thermal
vacu

um
valve

is

provided
for
this

purpose

r
rn

11

L

e

7

E
G
R

controlval
le
clo

2

When

engine
coolant

temperature

is
above

the

working

temperature
of

the
thermal

vacuum
valve

I
The
valve

port
come

to
the

top

J
It
remains

closed
while

engine
coolant

temperature
is
low
and

keeps
the

E
G
R
control
valve
closed

thereby

culling
off
the

E
G
R
circuit

I

lW
jS

1
Throttle
valve

Thermal
vacuum

valve
close

j
Note

m
Vacuum
condition

of
the

throttle
valve
du

ring

engine

idling
for

improved
idling

operation

At

this

point
vacuum
does
not

actuate

the
E
G
R
control
valve

r
T
D

L

t

i

q

II

E
G
R
control

valve

close

2
In
the
full

throttle

driving
posi

tion

the
suction
vacuum

on
the
vacu
JllrI

Thermal
vacuum
valve

ope

um

passage
does

not

surpass
the
vacu

um

required
to

actuate
the
E
G
R

EC
20
EC227

Fig
EC
49
E
G
R
not

actuated

though
intake

manifold

vacuum
is

high
and
E
G
R

control
valve
remain

closed

l

Throttle
valve

EC228

Fig
EC
50

E
G
R
nol

actualed

control

valve

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

j

EC231

Thermal

vacuum
valva
o

o

m
Emission

Control

System

0

o

o

o

l

l
@

The
thermal
vacuum
valve

is

mounted
in

the

engine
thermostat

housing
It

detects

engine
coolan
t

tem

perature
by
means
of
a

built
in

bi

metal
and

opensor
closes
the

vacuum

passage
in
the

thermal
vacuum

valve

mt

li

t

00
t

EC232

Fig
EC
54
Thennal

vacuum
valve
To
E

G
R
control
valve

From
carburetor

1

Spring

2
Bi
metal

3

O

ring

E
G
R

warning

system

The

E
G
R

warning
system
install
1

Diaphragm
spring

2

Diaphragm

3
Valve
shaft

4

Valve

5
Valve

Seat

6
Valve
cham
ber

Fig
EC
53
E
G

R
control
value

When
the

vacuum

passage
is

open
the

carburetor
suction

vacuum
is

applied

to
the

diaphragm
of
the
E
G
R

con

trol
valve
to

actuate
the

taper
valve

connected
to
the

diaphragm

theconsiiiictlo

nlie
thermal

vacuum
valve
is

shown
below

ed

independently
of
the

E
G
R

con

trol

system
monitors

the
distance
the

car
has
travelled
and

indicates
when

EC
22
the
E

G
R

control

system
must
be

checked

The
E
G
R

warning
system
consists

of

an
odometer
switch

detector
drive

counter
E

G
R

warning

lamp
and

harnesses

When
the

earn
in
the

odom

eter
switch
connected
to

the

speed

ometer
turns

once
for

each
OAkm
4

mile
the

contact

point
of
the
elec

trica
circuit
closes

allowing
electric

current
to
flow

through
the

magnet

coil
of

the
detector

drive
counter

Thus

energized
the

magnet
coil
ac

Wates

the
latchet
to

turn
the
c
unter

wheel

by
one

pitch
When
the

number

of

counts
reaches
50
000
the
latchet

drops
in

a

groove
provided
on
the

periphery
of

the
counter
wheel
to

activate

the
detector

drive
counter

switch

Then
the

E
G
R

warning

lamp

comes
on

indicating
that
the
E
G
R

control

system
Should
be
checked

The

detector
drive

coun
teT
is

equip

ped
with
an
odometer
which

can
tell

when
to
service

the
E

G
R
contr0
I

system

After

completing

periodic
check

reset
the
odometer
to

zero
by
hand

proceeding
as
follows

1
Remove

grommet
installed
on

the
side

surface
of

detector
drive

counter
unit

2
insert

a
bar

or
a
screwdriver

tip

into
the

hole
from

which

grommet
has

been

removed
and

press
down
knob

provided
in

the
detector
drive
counter

for

resetting

The
E

G
R

warning

lamp
comes

on

under
the

following
circumstances

1
When
the
number
of

counts
has

reached
50
000
In
this

case
the

lamp

indicates
that
E

G
R

control

system

must
be
checked

2
When

operating
starter
motor

Notes

a
It
is

an
indication
of

problem
in

the

E

G
R

warning
lamp
or

problems

in
the

point
or
in
the
harnesses
if

the

lamp
does
not

light
at

50
000

counts

b

The
E

G
R

warning
system
is

mounted

on
all
620
models

except

those

bound
for
California
and

Canada

1

1

I
I

I

1
v

v

I
I

I
I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

L
0

I

Magnet
coil

Detector
drive

counter

REMOVAL
AND

INSTALLATION

Remove
air
cleaner

before

removing

E
G
R
control

system
For
removal

and

installation
of
air

cleaner
refer
to

Air
Cleaner
section

Page
EF
S

Removal

I
E
G
R
control
valve

After

removing
the

following
parts

the
E

G
R

controi
valve
can

be
dis

mounted

Vacuum

hose
thermal
vacuum

valve
to
E
G
R

control
valve

E
G
R
control
valve

mounting
nut

Note
To
remove

vacuum
hose
flat

ten

clip
connecting
vacuum
hose
to

E
G
R
control
valve
and

pull
the

hose
off
with
hand
Emission
Control

System

Ignition
switch

E
G
R

warning
lamp

f

1
Ignition
switch

start

position

Fuse

1
A
Odometer
switch

r

I
I

I

I
v

I

I
I

i

lQ
U

1

mi

L
J

EC233

Fig
EC
55
E
G
R

warning
circuit

EC234

Fig
EC
56

Removing
KG
R
control

valve

2
E
G
R

pass
ge

After

removing
the

following

parts

the
E
G
R

passage
can
be
dismounted

Exhaust
gas
return

tube
exhaust

manifold

to
E
G
R

passage

B1ow

by
hose

cylinder
block

to

P
C
v
valve

Vacuum
hose
AB
valve
to
E
G
R

passage

E
G
R

passage
mounting
bolt

EC

23
EC541

Fig
EC
57

Removing
E
G
R

passage

3

Thermal
vacuum

valve

After

removing
the

following

parts

the
thermal
vacuum
valve
can
be
dis

mounted

Vacuum
hose

carburetor
to
ther

mal
vacuum
valve

Vacuum
hose
thermal
vacuum

valve

to
E

G
R
control
valve

Note
Drain

engine
coolant
before

dis

mounting
thermal
vacu
m
valve

Fig
EC
58

Removing
thermal

vacu
um
valve

4
E
G
R

warning
system

EC251

Detector
drive
counter

Detecfor
drive
counter
is
secured

on
the

top
of
R
H

hoodledge
panel
in

engine
room
To

remove
detector
drive

counter
disconnect
w
COJUlector

and

loosen
two
bolts

securing
detector

drive
counter
to
hoodledge

panel

2

E
G
R

warning
lamp

E
G
R

warning
lamp
is
mounted
at

the

top
cen
ter
of
instrument

pad
To

remove
E
G

R

warning
lamp
proceed

as
follows

1
Remove

masking
panel

On
models

equipped
with
radio

remove

warning
lamp
from
under
in

strument

panel

2

E
G
R

warning
lamp
is

a
twist

type

Remove

lamp
and
socket

as
an

assembly
Push
and
twist

lamp
off

can

EC554

Fig
EC
60
Removing
E
G
R

warning

lamp
Emission
Control

System

3
Odometer
switch

Odometer
switch
is
mounted
on
the

back
side
of

speedometer
Cam
in
the

odometer
switch
is
rotated

by
the

speedometer
To

dismount
odometer

switch

proceed
as
follows

I

Dismount
combination
meter
as

sembly

2
Remove
meter
front
cover
and

take
off

clips
and
screws
to

dismount

shadow

plate

3

Loosen
screws

securing
speed

ometer
to

printed
circuit

housing
then

remove

speedometer

4

Remove
two
screws

securing

odomete
switch
to
the

back
side
of

speedometer
and
detach
odometer

switch

EC239

Fig
EC
61

Removing
odometer

switch

InstaUatlon

To
install
reverse
the
removal

pro

cedure

EC24
V

r
CID

1
Detector
drive
counter

2
E
G
R
warning
lamp

3
Speedometer

Fig
EC
59
E
G
R

warning
y
tem

INSPECTION

Checking
E

G
R
control

system
in

its
mounted
conditionS

I

Make
a

thorough
visual
check
of

E

G
R
control

system
If

necessary

wipe
away
oil
to

facilitate

inspection

If

any
hoses
are
cracked
or

broken

replace

2

With

engine
running
check

E

G
R

warning
system
for

proper

function
Make
sure
that
E

G
R
warn

ing
lamp
lights
when

ignition
switch
is

turned

to
START

position
starter

mo

tor
runs
If
E
G
R

wanung
lamp
does

not

light
inspect
harnesses
and

con

nectors
or

replace
warning
lamp
Then

turn

ignition
switch
to
ON

position

and

check
the
following
items

I

If
odometer
of
detector
drive

counter
has
not
reached
50
000

counts
make
sure
that
E
G
R

warning

lamp
does
not
light

2
If
odomete
of
detector
drive

counter
has
attained
50
000
counts

make
sure
that
E
G
R

warning
lamp

lights

If

warning
lamp
does
not

light

check
harnesses
connectors
and
de

tector
drive
counter
replace
warning

lamp
or
detector
drive
counter
if

necessary

Notes

Operation
oC
E
G
R

warning
lamp

is
as
Collows

Ignition
Switch
Position
START

Detector
Drive

Counter

E
G
R

Warning
Lamp
ON

b
After

completing
inspection
of

E

G
R

control
system
be

sure
to

reset

odometer
of
detector
drive

counter
to

zero

c
This
item

applies
to
all
620
models

except
those
bound
for
California

and
Canada

3

With

engine
stopped
inspect

E
G
R
control
valve
for

any
indication

of

binding
or

sticking
by
moving
dia

phragm
of
control
valve

upwards
with

a

finger

2
When

engine
coolant

tempera

ture
is

high

I
Make

sure
that
E

G
R

control
valve

operates
when

engine
speed
is
in

creased
from
idling
to
3
000
to

3
500

rpm
Place
a

fmger
on
the

diaphragm
of
E
G
R
control

valve

to
check
for
valve

operation

2
If

E
G
R
control
valve
does
not

operate
check

as
follows

Disconnect
one
end
E

G
R
control

valve
side
of
vacuum
hose
connect

ing
thermal
vacuum
valve
to
E
G
R
Emission
Control

System

ON

Below

50
000
counts
Above

50
000
counts

OFF
ON

4
With

engine
running
inspect

E
G
R

control
valve
and
thermal
vacuo

um
valve
for
normal

operation

1
When

engine
coolant

tempera

ture

is
low

Make

sure
that
E
G
R

control
valve

does
not

operate
when

engine
speed
is

increased
from

idling
to
3
000
to

3
500

rpm

Place
a

fmger
on
the

diaphragm
of

E
G
R
control
valve
to

check
for
valve

operation

EC253

Fig
EC
62

Checking
E
G
R
control
valve

control
valve

Increase

engine
speed
from

idling
to

3
000
to
3

500

rpm

Make
su
re
that
thermal
vacu
um

valve
is

open
and
that

carburetor

vacuum
is

present
at
the
end

E

G
R
control

valve
side
of

vacu

um
hose

If
vacuum
is
weak
or

not

present
at

all

replace
thermal
vacuum
valve
If

vacuum
is

present
replace
E
G

R

control
valve

EC
25
EC254

Fig
EC

63

Checking
lhermal

vacuum
valve

If

any
difficulty
is
encountered
in

judging
the
condition
of

any

compo

nent

during
above

inspection
check

the

questionable
component
independ

ently
as

follows

E
G
R

control
valve

Dismount
E

G
R

control
valve

from

engine

I

Apply
vacuum
to

E
G
R

control

valve

referring
to
the

following
figure

If

the
valve

moves
to
full

position
it
is

normal

E
G
R

control
valve
will
remain

open
for
more

than
30

seconds
after

vacuum
has
cut

off

la

ET152

Fig
EC
64

Checking
E
G
R

control

ualue

2

Visually
check
E
G
R

control

valve
for

damage
wrinkle
or
defonna

tion

3

Clean
the

seating
surface
of

E
G
R
control
valve
with
a
brush

and

compressed
air

and
remove

foreign

matter
from
around
the
valve
and

port

EC350

Fig
EC
65

Cleaning
E

G
R
control

valve

Thermal

vacuum

valve

Dismount
thermal

vacuum
valve

from

engine

Note
Before

dismounting
drain
en

gine
coolant

from

engine

Apply
vacuum
to
thermal
vacuum

valve
and

check
to
be
sure
thaI
ther

mal
vacuum
valve

opens
or
closes
in

response
to

engine
coolant

tempera

ture
as

specified

Thermal
vacuum
valve

should

open

at
a

temperature
of
57
to
630C

135

to
1450F

completing
the

vacuum

passage

Note
Do

not
allow
water
to

get

inside

the
thermal
vacuum
valve

EC242

Fig
EC
66

Checking
hennal

vacuum

valve
Emission
Control

System

CATALYTIC

CONVERTER

DESCRIPTION

The

catalytic
converter
accelerates

the
chemical
reaction
of

hydrocarbons

HC
and
carbon
monoxide
CO
in

the

exhaust

gas
and

changes
them
into

non
harmful

carbon
dioxide

C02

OPERATION

Exhaust

gas
emitted

from
the
en

gine
contains

some
harmful
substances

due
to

incomplete
combustion
in
the

combustion
chamber
The

air

injection

system
is

designed
to

reduce
the
con

tent
of
such
substances
in

the
exhaust

gas
In

this

system
the

secondary
air

is

led
from
the
check
valve

and

injected

into
the

exhaust
manifold

With
this

injection
of
the

secondary
air

hydro

EC444

EC
26
and
water

H20
This
chemical
reac

tion

process
requires
the

proper
a

mount

of
air

which
is

supplied
by
the

air

pump
Refer
to

the
item
AJ

S

This
air
is
caUed

secondary
air

The

catalytic
converter
is
mounted

on
the

vehicles
destined

for
California
Refer

to

Figure
EC
67

3
4

1
Front
tube

2

Catalyti
converter

3
Center
tube
4
Main
muffler

5
Rear
tube

EC782

Fig
EC
67

Location

of
catalytic
converter

car

ons

He
and
carbon

monoxide

CO
in
the
exhaust

gas
are

gradually

oxidized
with

oxygen
02
in
the

secondary
air
and
converted

into
non

harmful
carbon

dioxide

C02
and

water

H20

The

catalytic
converter

further

cleans

engine
exhaust

gas
Through

catalytic
action
it

changes
residual

hydrocarbons
and
carbon
monoxide

contained

in
exhaust

gas
into
carbon

dioxide

and
water
before

exhaust

gas

is

discharged
to
the

atmosphere

c
Secondary
air

Carbon
monoxide

hydrocarbon

Carbon
dioxide
gas

water

F
EC
68

Operution
of
catalytic
corwerter

REMOVAL

AND

INSPECTION

Removal
and

inspection
can
be

done

as
follows

Removal

Catalytic
converter

1

Apply
parking
brake

2

Place
wheel
lock
under
each
tire

3

Jack

up
the
vehicle

4
Remove
lower
shelter
of

catalytic

converter

5
Dismount

catalytic
converter

EC453

Fig
EC
69
Removing

catalytic

conuerter

Inspection

Preliminary
inspection

Visually
check
condition
of
all

component
parts
including

ho
s

tubes
and
wires

replace
if

necessary

Refer
to

Inspection
of
A
I
S
on

page
EC
17

Catalytic
converter

Whether

catalytic
converter
is
nor

mal
or
not
can
be
checked
by
ob

serving
variation
in

CO

percentage

The

checking

procedure
is

as
follows

Apply
parking
brake
Shift

gears

into
Neutral
for
manual
transmission

and
Neutral
or
Park
for
automatic

transmission

1

Visually
check

catalytic
converter

for

damage
or
cracks
Emission
Control

System

2
Remove
air
hose
between

5

way

connector
and
air
check
valve

Plug
the

disconnected
hose
to

prevent
dust

from

entering
Refer
to

page
ET
12

3

Check
carburetor

pipes
for

proper

connection

4

Warm

up
engine
sufficiently

5

Race

engine
1

500
to
2
000

rpm

two
or
three
times

under
no
load
then

run

engine
for
o
e
minute
at

idling

speed

6

Adjust
throttle

adjusting
screw

until

engine
attains
to

specified
speed

Refer
to

page
ET
10

7
Check

ignition
timing
If
neces

sary
adjust
it
to

specifkations
Refer

to

page
ET
10

B

Adjust
idle

adjusting
screw
until

specified
CO

percentage
is

obtained

Refer
to

page
ET
12

9

Repeat
the

adju
stment

process
as

described
in

steps
5
to
8
above

until

specified
CO

percentage
is
obtained

Note

Adjustment
in

step
9
should
be

made
ten

minutes
after

engine
has

wanned

up

10
Race

engine

1
500
to
2
000

rpm
two
or
three
times

under
no
load

and
make
sure
that

specified
CO

per

centage
is
obtained

11
Remove

cap
and
connect
air

hose
to

air
check
valve

If

idling

speed
increases

readjust
it

to

specified
speed
with
throttle
ad

justing
screw

12
WaRn

up
engine
for

about
four

minutes
at
2
000

rpm
under
no
load

13
Measure
CO

percentage
at

idling

speed
After

step
12
has
been
coin

pleted
wait

for
one
minute
before

making
CO

percentage
measurement

14
If
CO

percentage
measured
in

step
13
is
less
than
0
3

the

catalytic

converter

is
normal

15
If
CO

percentage
measured
in

step
13
is
over
0
3

recheck
A
I
S

and

replace
air
check
valve
Then

perform
inspection
steps
12
and
13

EC
27
16
If
CO

percentage
is

still
over

0
3
in

step
15

catalytic
conyerter
is

malfunctioning
Replace
catalytic
con

verter

INSTALLATION

To
install

reverse
the
removal

pro

cedure

Bolt

lightening

torque

specifications

Tightening

torque

Catalytic
converter

2
6
to
3
4

kg
m

19
to
25
ft
Ib

FLOOR

TEMPERATURE

WARNING
SYSTEM

DESCRIPTION

The
floor

temperature
warning

system
consists
of
a
floor

temperature

sensing
switch
installed

on
the
vehi

cle
s
floor
floor

temperature
relay
and

a

warning

lamp
on
the
instrument

panel
and
wires
that
connect
these

parts

When
the
floor

tempera
ture
rises
to

an
abnormal
level
the

warning
lamp

will

light
to
call
the
attention
of
the

driver
The

wiring
diagram
of
this

system
and
location
of
the

floor

temperature
sensing
switch
are
ilIus

trated
in

Figures
EC
70
and
EC
71