ESP DATSUN PICK-UP 1977 User Guide

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

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

Step
system

The

construction
of
this

system

may

correspond
to
the

idling
and
slow

system
of

the

primary
system

Tlris

system
aims

at
the

proper

filling
up
of
the

gap
when

fuel

supply

is
transferred
from
the

primary
system

to
the

secondary
one
The

step
port
is

located
near
the

secondary
throttle

valve

edge
in
its

fully
closed

state

Secondary
switchover
mechanism

The

secondary
throttle
valve
is

linked
to
the

diaphragm
which
is

actuated

by
the
vacuum

created
in
the

venturi
A

vacuum

jet
is

provided
at

each
of
the

primary
and

secondary

venturies
and
the

composite
vacuum

of
these

jets
actuates
the

diaphragm

As
the

linkage
causes
the

secondary

throttle
valve
to
close
until
the

prima

ry
throttle
valve

opening
reaches

ap

proximately
500
fuel

consumption

during
normal

operation
is

not
exces

sive

During
high
speed
running
as

shown
in

Figure
EF
28
as
the

vacuum

at
the
venturi
is
increased
the
dia

phragm
is

pulled
against
the

diaphragm

spring
force
and
then

secondary
throt

tie
valve
is

opened

The
other

side

during
low

speed

running
as
the

primary
throttle
valve

opening
does
not
reach
500
the

secondary
throttle
valve
is

locked
to

close

completely
by
the

locking
arm

which
is
interlocked
with

primary

throttle
arm

by
linkage

When
the

primary
throttle
valve

opening
reaches
wider

position
than

500
the

secondary
throttle
valve
is

ready
to

open
because
the

locking

arm
revolves
and
leaves
from
the

se

condary
throttle
arm
Engine
Fuel

HI
h

speed
circuit

The
high

speed
circuit

improves

high
engine
output
performance

during
high

speed
driving

This
circuit

operates
only
when

driving
at

high
speed
It
consists
of
a
richer

jet
high
speed
enricher
air

bleed
and
richer
nozzle
When
the

velocity
of
suction
air

flowing

through

the

carburetor
secondary
bore
in

creases
additional
fuel
is
drawn

out
of

the

richer
nozzle

@
2

EF234

Secondary
I

Richer

jet

2

High
speed
enricher

air
bleed

3
Richer
nozzle
Primary

Fig
EF
29

High
speed
circuit

ANTI
DIESELlNG
SYSTEM

is

brought
into

operation
shutting
off

the

supply
of
fuel
to
the
slow
circuit

The

following
figure
shows
a

see

tiorial
view

of
this
control
The
carburetor
is

equipped
with
an

anti

dieseling
solenoid
valve

As
the

ignition
switch
is
turned
off
the
valve

EF230

@

l
CD

1

1
g

@eI

1
Anti
dieseling

solenoid
va1

2

Ignition
switch

3

Battery

Fig
EF
30
Schematic
drawing
of
anti

dieseling
sydtm

EF
17

ELECTRIC
AUTOMATIC

CHOKE

An
electric
heater
wanns
a
bi
metal

interconnected
to
the
choke
valve
and

controls
the

position
of
choke
valve

and
throttle
valve
in
accordance
with

the

time

elapsed
the
warm

up
condi

tion

of
the

engine
and
the

outside

ambient

temperature

When
outside
ambient

temperature

is

above

operating
temperature
the

automatic

choke
control
serves
to
fur

ther
reduce
exhaust

gasemission

during
warm

up
by
automatically

selecting
one
of
the
two

choke

opera

tion
modes
fast

acting
or
slow

acting

Slow

acting
choke

operation

When
ambient

temperature
is
low

electric
current
flows

through
the

automatic

choke

relay
to
the
P
T
C

heater
A

and

gradually
warms
the

bi

metal
This
causes
the
choke
valve

to

open
slowly

Fast

acting
choke

operation

When
ambient

temperature
is

high

the
bi
metal
switch
is
in

on
This

causes
electric

current
to
flow

through

the
automatic

choke

relay
to
the

P

T
C
heater
A
and
heater

B
result

ing
in

quick

opening
of
the

choke

valve

r

@@

r

@
Engine
Fuel

The

construction
and

function
of

each

part
of

this
carburetor
are
as

follows

l
Bi
metal
and
heater
in
choke

cover

Electric
current

flows

through
the

ttea
r
as

t
le
engine
tl

1
SI
nd
war

the
bi
metal

The
deflection
of
the

bi
metal
is
transmitted
to
the
choke

valve

through
the
choke

yalve
lever

2
Fast
idle
cam

The
fast
idle

cam
determines
the

opening
of
the
throttle
valve

so
that

the

proper
amount
of

mixture
cor

responding
to
the

opening
of
the

choke
valve
will
be
obtained
The

opening
of
the

choke
valve
is

depend

ent

upon
the
warm

up
condition
of

the

engine

3

Fast
idle

adjusting
screw

This

screw

adjusts
the

opening
of

the
throttle

valve
of
the
fast

idle
earn

4
U

nloader

When

accelerating
the

engine
during

the

warm

up
period
that
is

before
the

choke

valve

opens
sufficiently
this

unloader
forces

the
choke
valve

open
a

liUle
so

as
to
obtain

an

adequate

air
fuel

mixture

5

Vacuum

diaphragm

After

the

enginThas
been

started

by
cranking
this

diaphragm
forces

the

choke
valve

open
to
the

predetermined

extent
so

as
to

provide
the

proper

air
fuel
ratio

6
Bi
metal

case
index
mark

The
bi
metal

case
index
mark
is

used

for

setting
the

moment
of
the

D

Il

EF232

1

Alternator

2
Automatic
choke

relay

3
Automatic
choke
cover

4
P

T
C
heater
A

5
Bi
metal
switch

6
P

T
C
heater
B

7
Bi
metal

8
Choke
valve

Fig
EF
33
Schematic

drawing
of
electric
automatic
choke
heater

EF

20
bi
metal
which

controls
the
air

fuel

mixture
ratio

required
for

starting

DASH
POT

SYSTEM

These
carburetors
are

equipped

with

a
dash

pot

interl
ked
wi
h

the

primary
throttle

valve

through
a
link

mechanism
The

dash

pot
is
intended

to

prevent

engine
stall

resulting
from

quick
application
of
the
brake
or

from
the

quick
release
of
the
accele
ra

tor

pedal
after

treading
it

slightly

In

such
a

situation
a
throttle
lever

strikes

against
the
dash

pot
stem
and

makes
the

primary
throttle
valve
close

gradually
thus

keeping
the

engine

running

ALTITUDE
COMPENSATOR

California
models

The

higher
the
altitude
the
richer

the
air

fuel
mixture
ratio
and
there

fore
the

higher
exhaust

gas
emissions

even

though
the

engine
is

properly
ad

justed
for
low

altitude

driving

The
altitude

compensator
is

design

ed

to
meet
EiiriSSion
S13ndards
for

driving
in
both
low
and

high
altitudes

At

high
altitudes
additional
air
is

sup

plied
to
the
carburetor

by
the
altitude

compensator
When
the
altitude

com

pensator
lever

is
set
at
H
air
is

conducted

through
an
air

passage
to

the

carburetor
The
air

passage
is

closed
when
the
lever

is
set
at
L

H

L
Lever

When

operating
the
H

L
lever
fol

low
these

instructions

H

position

Should
be
used
for

general
driving

in

those
areas

designated
by
law

as

High
Altitude
Counties

L

position

For
use
outside
those
areas

desig

nated
as

High
Altitude
Counties

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

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

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

Emission
Control

System

EARLY

FUEL

EVAPORATIVE

SYSTEM
E

F
E

DESCRIPTION
spring
and

counterweight
which
are

assembled
on
the

valve
shaft

projecting

to
the

rear
outside
of
the
exhaust

manifold
The

counterweight
is
se

cured
to
the
valve
shaft
with

key
bolt

and

snap
ring
EC
4
A

control
valve
welded
to

the

valve
shaft
is

wtalled
on
the

exhaust

manifold

through

bushing
This
con

trol

valve
is

called
Heat

control

valve
The
heat
control

valve
is

ac

luated

by
the

coil

spring
thermostat
Construction
of
the

early
fuel

evap

orative

system
is

shown
in

Figure

r
I

1

@

rW

9

Sc
w

10
Thennostat

spring

11

Coil
spriiig

12
Control
valve
shaft

13
Heat
control

valve

14

Bushing

15

Cap

16
Exhaust
manifold
1
Intake
manifold

2
Stove

gasket

ManifoktstOve

4
Heat
shield

plate

5

Snap
ring

6

Counterweight

7

Key

g

Stoppel
pin

EC532

Fig
EC
4
Early
Fuel

Evaporutive
tem
E
F
E

The

early
fuel

evaporative
system
is

provided
with
a
chamber
above

a

manifold
stove
moonted
between
the

intake
and
exhaust

manifolds

During

engine

warming
up
air
fuel
mixture
in

the

carburetor
is

heated
in
the
cham

bet

by
exhaust

gases
This
results
in

improved
evaporation
of

atomized
fuel

droplets
in
the
mixture
and
in

smaller

content
of

hydrocarbons
He
in
the

exhaust

gas
especially
in

cold
weather

operation

The
exhaust

gas
flow
from
the

engine
is

obstructed

by
the
heat
con

trol

valve
in
the

exhaust
manifold
and
is

changed
in

direction
as
shown

by

the
solid

lines
in

Figure
EC
4
The

exhaust

gas
heats
the
manifold
stove

Open
close

operation
of
the

heat

control
valve
is
controlled

by
the

counterweight
and
thermostat

spring

which
is
sensitive
to
the

ambient
tem

perature
around
the

exhaust
manifold
With
this
condition
the

heat
control

valve
is
in

the

fully
closed

position

obstructing
the
flow
of

exhaust

gas
As

engine
tempera
lure

goes
up
and

the

ambient

temperature
becomes

high

enough
to
actuate
the
thermostat

spring
the

counterweight
begins
to

rotate
clockwise
and

again
comes
into

con

tact
with

the

stopper
pin
With
this

condition
the

heat
control
valve
is
in

the
full

open
position
and
exhaust

gas

passes
through
the
exhaust
manifold
as

shown

by
the
dotted

lines
in

Figure

EC
4
without
heati

ng
the
manifold

stove
OPERATION

The

counterweight
rotates
counter

clockwise
and

stops
at

the

stopper
pin

mounted
on
the
exhaust

manifold

while

the

engine
temperature
is
low

EC
6

Air
control
valve

CalifornIa
models

The
air
control
valve

con
troIs
the

quantity
of

secondary
air
fed

from
the

air

pump
according
to

engine
speed

and

load
condition
and

prevents
ex

cessive

temperature
rise
of
the

cataly

tic
converter

The
construction
is
as
shown
in

Figure
EC
16
The
intake
manifold

vacuum
and
air

pump
discharge
pres

sure

applied
to

the

diaphragm
chamber

actuate
the

valve
which
is

coupled
to

the

diaphragm
and
control
the

quanti

ty
of

secondary
air
to
be
fed
into
the

exhaust
manifold
in

response
to
the

engine
condition

c
From

air

pump

To

carburetor

air
cleaner

lr

J

EC291

Fig
EC
16
Air
control
valve

Anti
backfire
valve

This

valve
is

con
trolled

by
intake

manifold
vacuum
to

prevent
backfire

in
the

exhaust
system
at

the
ini

tial

period
of
deceleration

At
this

period
the
mixture
in
the

intake
manifold
becomes
too

rich
to

ignite
and
burn
in
the

combustion

chamber
and
burns

easily
in
the
ex

haust

system
with

injected
air
in
the

exhaust
manifold

The
anti
backfire
valve

provides
air

to
the
intake
manifold
to
make
the

air
fuel
mixture
leaner
and

prevents

backfire

A
schematic
drawing
of
the
anti

backfire
valve
is
shown
in

Figure

EC
17

The
anti
backfire
valve
inlet
is

con

nected
to
the
air
cleaner
and
the

outlet

to
the
intake
manifold

Th
correct
function
of
It
jS
valve

reduces
hydrocarbon
emission

during

aeceleration

If
the
valve
does
not
work

properly

unburned
mixture
will
be

emitted
Emission
Control

System

from
the
combustion
chambers
and

burns
with
the
aid
of
high

temperature

and

injected
air

which
causes
backfire

I
Tointake

c
manifold

vacuum

I

L

AirdisChaJ1le

I

to
mtake

manifold
From
air

cleaner

ECQ69

Fig
EC
11
Anti
back
ir
valve

Check
valve

A
check
valve
is
located
in
the
air

pump
discharge
lines
The
valve

pre

ven
ts
the
backflow
of
exhaust
gas

which
occurs
in

one
of
the

following

cases

1
When

the
air

pump
drive
belt

fails
2
When
relief
valve

spring
fails

Construction
is

shown
in

Figure

EC

18

F
rom

m

pump

1

Spring

2

Rubber
valve

3

Seat
Secondary
air

Exhaust

gas

EC292

Fig
EC
1B
Check
valve

AIr

InJaction
Into
axhaust

port

The

secondary
air

fed
from
the
air

pump
goes
through
the

check
valve
to

the
air

gallery
where
it
is
distributed
to

each
exhaust

port
The

secondary
air

is
then

injected
from
the
air

injection

nozzle
into

the
exhaust

port
near
the

exhaust
valve

n

L
y

r

V

Air
pump
relief
valve

The
air

pump
relief
valve

controls

the

injection
of
the

secondary
air
into

the
exhaust

system
when
the

engine
is

EG
11
3
I
Air

gallery

2

Exhaust
port

3
Air

jnjection
nozzle

4
Exhaust

manifold

EC293

Fig
EC
19
Air
injection
into
exhaust

port

running
at

high
speed
under
a

heavily

loaded
condition
It

accomplishes
the

following
functions
without

affecting

the

effectiveness
of
the
exhaust
emis

sion
control

system

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