1977 DATSUN PICK-UP check engine

CHECKING
CHOKE

MECHANISM
Choke

plate
and

linkage

1
Check
choke

valve
and
mech

anism

for
free

operation
and
clean
or

replace
if

necessary
A
binding
can

result
from

petroleum

gum
formation

on
choke
shaft

or
from

damage

2

Check
bimetal
cover

setting

Index
mark

on
bimetal

cover
is

usually

set

at
center
of
scale

Note

Always
align
the
index

mark
on

bimetal
cover
with
the
center
index

mark
on
choke

housing

3

Every
day
before

starting
engine

depress
the
accelerator

P
dal
to
see
if

choke
valve
is
closed

automatically

If
it
fails
to
be
closed
the

chances

are
that
link
movement
is
unsmooth
Engine
Tune

up

or
that
bimetal
is

out
of
order
Refer

to
Carburetor
in
Section
EF

CHECKING
FUEL

LINES
Hoses

pipings
connections

etc

Check
fuel
lines
for

loose
con

nections

cracks
and

deterioration

Retighten
loose
connections

and
re

place
any
damaged
or
deformed

parts

REPLACING
FUEL

FILTER

Check
for
a

contaminated
filter
and

water

deposit
All

engines
use
a

replaceable

cartridge
type
fuel
filter
as
an
as

sembly

@

Fig
ET

19
Fuel

filler
ET011

EMISSION
CONTROL
SYSTEM

CHECKING
CRANKCASE
EMISSION

CONTROL
SYSTEM

REPLACING
P
C
V
VALVE
AND

FILTER

CHECKING
VENTILATION
HOSE

CHECKING
EXHAUST
MANIFOLD
HEAT

CONTROL
VALVE

CHECKING
SPARK
TIMING

CONTROL

SYSTEM

SPARK
DELAY
VALVE

Automatic
transmission
models

only

INSPECTION

CHECKING

AUTOMATIC
TEMPERATURE

CONTROL
AIR

CLEANER

OPERATING
PRESSURE
OF

BOOST

CONTROLLED
DECELERATION
DEVICE

B
CD
D
I
ADJUSTMENT

CHECKING
B
C
DD
CIRCUIT

WITH

FUNCTION
TEST

CONNECTOR

CHECKING

CRANKCASE

EMISSION

CONTROL

SYSTEM

REPLACING
P
C
V
VALVE

AND
FILTER

Check
P

C
V

valve
in

accordance
CONTENTS

ET
13

ET
13

ET
14

ET
14

ET
14

ET
14

ET
15

ET
15

ET
17

ET
17
ADJUSTMENT
OF
SET
PRESSURE
OF

BOOST

CONTROLLED
DECELERATION

DEVICE
B

CD
D

CHECKING
B
C
D
D
SOLENOID
VALVE

CHECKING
AMPLIFIER
Manual

transmission
models

REPLACING
AIR
PUMP
AIR
CLEANER

ELEMENT

CHECKING
EXHAUST
GAS
RECIRCULA

TION
E
G
R
CONTROL
SYSTEM

CHECKING
EVAPORATIVE
EMISSION

CONTROL

SYSTEM

CHECKING
CATALYTIC
CONVERTER

INSPECTION

CHECKING
FLOOR
TEMPERATURE

WARNING
SYSTEM

INSPECTION

with
the

following
method

With

engine
running
at

idle
remove

ventilator
ose
from
P
C
V

valve
If

the
valve

is

properly
working
a

hissing

ET
13
ET
18

ET
20

ET
20

ET
20

ET
20

ET
22

ET

23

ET
23

ET

23

ET
23

noise
will
be

heard
as
air

passes

through
the

valve
and
a

strong
vacuum

should
be
felt

immediately
when

a

finger
is

placed
over
valve
inlet

Fresh
air

Blow

by
gas

CHECKING

VENTILATION

HOSE

1

Check
hoses
and
hose
connec

tions
for
leaks

2
Disconnect
all
hoses
and
blow

them
out
with

compressed
air

If

any
hose

cannot
be
free
of

obstructions

replace

Ensure
that
flame

arrester
is

surely

inserted
in
the

hose
between
air

cleaner
and
rocker
cover

CHECKING
EXHAUST

MANIFOLD
HEAT

CONTROL
VALVE

Run

engine
and

visually
check

counterweight
to
see

if
it

operates

properly

I
For

some
time

after

starting

engine
in
cold

weather

counterweight

turns

counterclockwise
until

it
comes

into

contact
with

stopper

pin
installed

to

exhaust
manifold

Counterweight

gradually
moves

down

clockwise

as

engine
warms

up

and
ambient

temperature
goes
higher

around
exhaust
manifold

2

When

engine
speed
is

increased

discharge
pressure
of
exhaust

gases

causes

counterweight
to
move
down

ward

clockwise
Engine
Tune

up

CoOl
1

Oil
level

gauge

2

8affle

pia
te

3

Flame
arrester

4

Filter

5
P
C
V
valve

6

Steel
net

7

Baffle

plate

1fiI

o

EC716

Fig
ET
20
Crankcaae
emi
ion

control8
tem

3
When
heat

control
valve
is
in
the

full

open

position
counterweight

moves
further

clockwise

exceeding
the

position
described

in
1

1
above
and

stops

again
coming
into

contact
with

stopper

pin

ct

t

C

EC245

1

Counterwe
ht

2

Stopper
pin

3

Heat
control

valve

Fig
ET
21
Cold

operation
of
counte

weigh
t

EC246

1

Counterweight

2

Stopper
pin

3
Heat
control
valve

Fig
ET

22
Hot

operation
of
counter

weight

ET

14
2
With

engine

stopped
visually

check

E
F
E

system
for
the

following

items

I
Thermostat

spring
for
dismount

ing

2

Stopper

pin
for

bend
and
count

er

weight
stop
position
for

dislocation

3

Check
heat
control

valve
for

malfunction

due
to
break
of

key
that

locates

counterweight
to
valve

shaft

4

Check
axial
clearance

between

heat
control

valve
and
exhaust
mani

fold
Correct
clearance
is
0
7
to
1
5

mm
0
028
to

0
059
in

5

Check
welded

portion
of

heat

control

valve
and

valve
shaft
for

any

indication
of
crack

or

flaking

6
Rotate
heat

control
valve

shaft

with
a

fmger
and

check
for

binding

between

shaft
and

bushing
in

closing

and

opening
operation
of
heat
control

valve
If

any
binding
is
felt
in

rotating

operation
move
valve
shaft
in

the

rotation
direction
several
times
If

this

operation
does
not

correct

binding

condition
it
is
due

to
seizure
between

shaft
and

bushing
and

exhaust
mani

fold

should
be

replaced
as
an
assem

bly

CHECKING
SPARK

TIMING
CONTROL

SYSTEM

This

system
is

installed
on
non

California
automatic
transmission

models

SPARK
DELAY
VALVE

Automatic
transmission

models

only

This
valve

delays
vacuum

spark

advance

during
rapid
acceleration
it

also
cuts

off
the

vacuwn

spark
advance

imme

iately
upon
deceleration

The

valve
is

designed
for
one

way
opera

tion

and
consists

of
a
one

way
umbrel

la
valve
and
sintered
steel
fluidic

restrictor

Engine
Tune

up

EC284

When

installing
this
valve

ensure

that
it

properly
oriented
This
valve

should
be

replaced
periodically
Refer

to
Maintenance
Schedule

I

To

distribut0
From

carburetor

Yl
r

EC278
l

Fig
ET
24
Operation
of
spark
delay

value

I

I

Carburetor
side

Distributor
side

rJmlL
lr

EC346

Fig
ET
25
Checking

spark
delay
value
Distributor
side

Brown

lOne
way
umbrella
valve

2
Sintered
metal
disc

Fig
ET
23
Spark
delay
valve

INSPECTION

I
Remove

spark
delay
valve

2
Blow
air

through
port
on

carbure

tor
side
then

through
the

other
port

on
distributor
side

Spark
delay
valve

is
in

good
condition
if
when

finger
is

placed
over

port
on
distrib
side

ajr
flow
resistance
is

greater
than
that

on
the
other

side
See

Figure
ET
25

3
If
a
considerable
air
flow
resist

ance
is
felt
at

port
on
distributor
side

in

step
2

above
and

if
the
condition
of

spark
delay
valve
is

questionable
dip

port
on
carburetor

side
into
a

cup

fIlled
with
water
Blow
air

through
the

other

port
Small
air
bubbles
should

appear

EC279

Fig
ET
26

Checking
spark
delay
ualue

Note
Be

careful
to

avoid

entry
of
oil

or
dirt
into
valve

ET
15
CHECKING

AUTOMATIC

TEMPERATURE

CONTROL
AIR

CLEANER

1
Air
cleener
element

Viscous

paper
type
air
cleaner
ele

ment
does
not

require
any
cleaning

opera
tion

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
Schedule

2
Hot

elr
control
system

In
warm
wealher
it
is
difficult
to

find
ou

t
malfunction
of
hot
air
control

system
In
cold
weather
however

malfunction
of
air
control
valve
d

e
to

disconnection
or
deterioration
of
vacu

um
hose
between
intake
manifold
and

vacuum
motor
and
insufficient
dura

bili

ty
of
air

con
trol
valve
will
cause

insufficient
automatic
control

opera

tion
for
intake
air
and
result
in

engine

disorder

including

I

Stall
or
hesitation
of

engine

opera

tion

2

Increase
in
fuel

consumption

3
Lack
of

power

These

phenomena
reveal
malfunc

tionof
hot
air
control

system
If
these

phenomena
should
occur
check
hot

air
control

system
as
described
in
the

following
before

carrying
ou

t

inspec

tion
of
carburetor

2
1
Vacuum
hoses

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

1

Check
that
vacuum
hoses
are
se

curely
connected
in

correct

position

2
Check
each
hose
for
cracks
or

distortion
hose

clip
for
condition

Note
Vacuum
hose

position
R
R

side
of
Nissan
mark
on
the

top
of

sensor
for

intake
manifold
L
R

side
of
the

mark
is
for
vacuum

rootor

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

control
valve
is
in

correct

position

EF213

Fig
ET
27

Impecting
lJalv

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
Engine
Tune

up

EF217

Fig
ET
28

lmpecting
value

position

Correct

pC6ition
of
air

control
valve

is
the

reverse
of

paragraph
I
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
is

open
posi

tion
as
descnbed
in

paragraph
2

above

pinch
vacuum
hose
with

fingers

and
cut
of
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
sensor

Check

temperature
sensor
for
func

tion

by
proceeding
as
follows
Be

sure

to

keep
engine
cold
before

starting

test

1
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
1
under

hood
air

inlet
is

closed
and
hot
air

inlet
is

open

ET

16
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

opera
tion
of
air

con
trol
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

tempera
ture
around
sensor
can

be
measured
In
this
case
fix

wiring
of

thermistor
or
thermometer
on
the
bot

tom
surface
of
air

cleaner
with
adhe

sive

tape
in

such
a
manner
that

the
set

position
of

temperature
sensing
ele

ment
will
not

be
affected

by
airflow

Then
install
air
cleaner
cover

EF221

Fig
ET
29
Checking
temperotur
e

ensor

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
severa
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
Section
EF

page
EF
8

OPERATI
NG

PRESSURE
OF

BOOST
CONTROLLED

DECELERATION

DEVICE
B
C
D
D

ADJUSTMENT

CHECKING
a
C
D
D
CIRCUIT

WITH
FUNCTION
TEST

CONNECTOR

Manual
transmission
models

I

Check
for

continuity
between

@

and@
at
a

speed
of
zero
km
Refer

to

Figure
ET
30

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

@
and

@
at
a

speed
of
more

than
16
km
h

10
MPH
Refer
to

Figure
ET
31

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

Automatic
transmission

models

I

With
inhibitor

switch
ON
UN

or
P

position
check
for

presence
of

voltage
across

@
and

@
Refer
to

Figure
ET
30

If

voltmeter

reading
is

12
volts

d
c

B
C
D
D

circuit
is

func

tioning
properly
Engine
Tune

up

If
voltmeter

reading
is

zero
check

for
disconnected

connector

faulty

solenoid
valve
or
inhibitor
switch
erly

If
ohmmeter

reading
is

32
ohms
or

above
check
for

poor
connection

of

connector

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
removed

and
tested

again
If

necessary
replace
2

With
inhibitor

switch
OFF

41
2
D
or
R

position

check
for
resistance

between

@
and

@
Refer

to

Figure
ET
31

If

ohmmeter

reading
is
25
ohms
or

below
circuit
is

functioning
prop

l

E
r
1

Ignition

key

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
ET

30
B
C
D
D
circuit
with

function
tedconnectoT

Manual
transmission
modela

@

1

Ignition

key

2

Inhibitor
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
ET
31

Checking
B
C
D
D
circuit
with
function
tf
st
connf
ctor

Automatic
transmiMion
modtla

ET
17

r

ADJUSTMENT
OF
SET

PRESSURE
OF
BOOST

CONTROLLED
DECELERATION

DEVICE
B

C
D
D

Generally
it
is

unnecessary
to

ad

just
the
B
C
D

D
however
if
it

should

become

necessary
to

adjust
it

the

procedure
is

as
follows

Prepare
the

foUowlnB
tools

I

Tachometer
to
measure
the
en

gine

speed
while

idling
and
a
screw

driver

2
A

vacuum

gauge
connecting
pipe

Note
A

qui
k

response
type
boost

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
D
D

solenrod

VT

FJ

1
B
C
D
D

solenni

valve
harness

J

ri

y

EF262

F
g
ET

32
Removing
harneS5

of

solenoid

valve

2
Connect
rubber
hose
between

vacuum

gauge
and
intake
manifold
as

shown

Fig
ET

33

Connecting
vacuum

gauge

3

Warm

up
the

engine
until
it
is

heated
to

operating

temperature

Then

adjust
the

engine
at
normal
Engine
Tune

up

idling
setting
Refer
to
the

item

Idling
Adjustment
in

page
ET
II

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

pressure
increases

abruptly
to
600

mmHg
23
62

inHg
or
above

and

then

gradually
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
pressure

Manual
transmission

510
to

550

mmHg

20
1
to
21
7

inHg

Automatic
transmission

490
to
530

mmHg

19
3
to
20

9

inHg

Note

When

checking
the
set

pressure

of
B
C
D
D

find
the

specified
set

pressure
in

Figure
IT

36
from
the

atmospheric
pressure
and
altitutde

of
the

given
location

For

example
if
a

manual
transmis

sion

model
vehicle
is

located
at

an

altitude

of
1
000
m

3
280
ft
the

specified
set

preSsure
for
B

C
D
D

445

mmHg
17
5

inHg

7

If
it
is

higher
than
the
set

level

turn
the

adjusting
screw

counter

clockwise

or
nut

clockwise
until

correct

adjustment
is

made

Non
California

models

Adjusting
screw

type

California

models

Adjusting
nut

type

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

ET

18
Non
california

models

1

Adjusting
screw

2

Cover
e

ET037

California
models

r

1

Adjusting
nut

2

Lock

spring

EC692

Fig
ET
34

Adjusting
Bet

pressure

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

D
The

engine

speed
will
not

drop
to

idling
speed

when
the

negative
idling
pressure
is

higher
than
the

set

pressure
of

the

B

C
D
D

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

krn
h

40

to
50
MPH
in

top
gear
manual

transmission
or
in
D

position
auto

matic
transmission

and
then

releasing

the
accelerator

pedal
and

letting
the

vehicle

decelerate
After

doing
this

check

whether
the
B

C
D
D
set

pres

sure
is
at
the

predetermined
value

or

not

r

CHECKING
B
C

D
D

SOLENOID
VALVE

I
Turn
on

engine
key
Do
not
start

engine

2
Ensure
that
solenoid
valve

clicks

when

intermittently
electrified
as

shown
in

Figure
ET
37

Fig
ET

37

Checking
solenoid
uolV
l

I

l

EF264

2

Turn

ignition
key
to
ON

posi

tion

3

Ensure
that
tester

pointer
deflects

when

ignition
key
is

turned
on

4

If

tester

panter
does
not
deflect

when

solenoid
valve

and

speed
detect

ing
switch

circuits

are

functioning

properly
amplifier
is

faulty
Engine
Tune

up

3
If
a

click
is

heard
solenoid
valve

is
normal

4

If
a
click
is
not
heard

at
all
check

for

continuity
with
a
circuit

tester
If

discontinuity
is

detected

replace
sole

naid
valve

CHECKING

AMPLIFIER

Manual
transmission

models

The

amplifier
is

installed
at
the

rear

of
the

speedometer
To

check

proceed

as
follows

1
Set
circuit

tester
in

d
c

ampere

range
IA

min
full
scale

connect
test

probes
of
tester
as

shown
in

Figure

ET
38

Do

not
confuse

positive
line

with

negative
line

M

p
1

II

L
o

A

I
of

j
t
J

f

T

1

Ignition
key

2

Amplifier

3

Speed

detecting
switch

4
B

C
D

D

solenoid
valve

Fig
ET
38

Checking

amplifiu

REPLACING
AIR

PUMP
AIR
CLEANER

ELEMENT

Remove
air

hose
then
detach
air

cleaner
from

hoodledge
Air
cleaner

element

and
air

cleaner
lower

body
are

built
into

a
unit
construction

Replace

air

cleaner
element
and
lower

body
as

an

assembly

ET

20
EC323

Fig
ET
39

Repl4cing
air
cleaner

element

CHECKING

EXHAUST

GAS

RECIRCULATION

E
G

R

CONTROL

SYSTEM

Checkln

E
G
R
control

system
In
Ita

mounted

condition

I

M
ake
a

thorough
visual
check
of

E

G
R
control

system
If

necessary

wipe
away
oil
to

facilitate

inspection

If

hoses
are

cracked
or

broken
fe

place

2
With

engine
running
check

E
G
R

warning
system
for

proper

function
Make
sure
that
E

G
R
warn

ing
lamp
light
when

ignition
switch
is

turned
to
START

position
starter
mo

tor
runs
If
E
G
R

warning
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
odometer
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

connector
and
de

tector
drive
counter

replace

warning

lamp
or
detector
drive

counter
if

necessary

Note

Operation
of
E

G
R

warning

lamp
is

as
follows

Ignition
Switch
Position
START

Detector
Drive
Counter

E

G
R

Warning
Lamp
ON

a
After

completing
inspection
of

E
G
R
control

system
be
sure
to

reset
odometer
of
detector
drive

counter
to
zero

b
This
item

applies
to
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
movirig
dia

phragm
of
control
valve

upwards
with

fmgers
Engine
Tune

up

ON

Below

50

000
counts
Above

50
000
counts

OFF
ON

4
With

engine
running
inspect

E
G
R
control
valve
and
thermal

vacu

um
valve
for

normal

operation

I
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

fingers
on
the

diaphragm
of

E
G

R
control
valve
to
check
for
valve

operation

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

fingers
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
ofvacuum
hose
connect

ing
thermal
vacuum
valve
to

E
G
R
EC253

Fig
ET
40

Checking
E
G
R
control
valve

control
valve

Increase

engine
speed
from

idling
to

3

000
to
3
500

rpm

Make
sure

that
thermal
vacuum

valve
is

open
and
that
carburetor

vacuum
is

present
at
the
end

E
G
R
control
valve

side
ofvacu

urn
hose

If
vacuum
is
weak
or
not

present
at

all

replace
thermal
vacuum
valve
If

vacuum
is

present
replace
E

G
R

con
trol
valve

ET
21
EC254

Fig
ET
41

Checking
thermal

vacuum

valw

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

0

r11

hC

J

ET152

Fig
ET
42

Checking
E
G
R
control

VGlve

2

Visually
check
E
G
R
control

valve
for

damage
wrinkle
or
deforma

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