check engine DATSUN PICK-UP 1977 Manual PDF

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

Condition

Engine
hesitation

Engine
does
not

start
Engine
Fuel

Probable

cause

Main

jet
or
slow

jet
clogged

By
pass
hole
idle

passage
dogged

Emulsion
tube

dogged

Idling
adjustment
incorrect

Secondary
throttle
valve

operating

im

properly

Altitude

compensator
setting
incorrect

Cali

fornia
models

Fuel
overflows

No
fuel

Idling

adjustment
incorrect

Fast
idle

adjustment
incorrect

Damaged
anti
dieseling
solenoid

EF
37
Corrective
action

Clean

Clean
tube

Clean

Adjust

Overhaul
and
clean

Correct
H
L
lever

position

See
condition
overflow

Check

pump
fuel

pipe
and
needle
valve

Adjust

Adjust

Replace

There
are
three

types
of
control

system
These
are

J

Closed

type
CIllnkcase
emission

control

system
Emission
Control

System

of

GENERAL

DESCRIPTION

2

Exhaust
emission

control

system

3

Evaporative
ell
lhsion

control

sys

tem

Pericxiic

inspection
and

required
seCV1Clng
of
these

systems
should
be

carried
out

to
reduce

harmful
emis

sions
to
a
minimum

CRANKCASE
EMISSION
CONTROL

SYSTEM

c

01

Lkf

If
1

TIL
II
tll

1

j

GUuuu
DESCRIPTION

This

system
returns

blow

by
gas
to

both
the
intake
manifold
and
carbure

tor
air

cleaner

The

positive
crankcase
ventilation

p
C
V

valve
is

provided
to
conduct

crankcase
blow
by

gas
to
the
intake

manifold

During

partial
throttle

operation
of

the

engine
the
intake
manifold
sucks

the
blow

by
gas
through
the
P
C
V

valve

Normally
the

capacity
of
the

valve

is

sufficient
to
handle

any
blow

by
and

a
small
amount
of

ventilating
air

4

c
Fresh
air

Blow
by

gas
The

ventilating
air

is
then

drawn

from

the
dust
side
of
the
cadlUretor

air
cleaner

tluough
the
tube

con

necting
carburetor
air
cleaner
to
rock

er
cover
into
the

crankcase

Under
full
tluottle

condition
the

manifold
vacuwn
is

insufficient
to

draw

the
blow

by
flow

tluough
the

valve
and
its

flow

goes
through
the

tube
connection
in
the

reverse
diree

tion

On
vehicles
with
an

excessively

high

blow

by
some
of
the
flow
will

go

through
the
tube

connection
to

carbu

retor
air
cleaner
under
all
conditions

1

Sealtypc
oil
level

gauge

2
Bame

plate

3
Flame
arrester

4
Filler

5
P
C
Y
valve

6
Steel
net

7
Bame

plate

EC716

Fig
EC

l
Crankcase
miaion
control

ay
tem

EC

2
INSPECTION

P
c
V
VALVE
AND

FILTER

Checking
P
C
V
valve
in

accord

ance

with
the

following
method

With

engine
running
at
idle

remove

the

ventilator
hose
from
P

C
V
valve

if
the

valve
is

working
a

hissing
noise

will
be
heard
as
air

passes

through
the

valve

and
a

strong
vacuwn
should
be

felt

immediately
when
a

fmger
is

placed
over
valve
inlet

Replace
P
C
V
valve
and

filter
in

accordance
with
the
maintenance

schedule

VENTILATION
HOSE

1

Check
hoses
and

hose
connec

tions
for
leaks

2
Disconnect
all
hoses

and
clean

with

compressed
air

If

any
hose
cannot
be
free
of

obstructions

replace

Ensure
that
flame
arrester

is

surely

inserted
in

hose
between
air
cleaner

and
rocker
cover

REMOVAL
AND
INSTAUATION
Emission
Control

System

EC533

Remove

snap
ring
D
and
lock
bolt

@
and
the

following
parts
can
be

detached
from
heat
control
valve

shaft

Key
00

Counterweight
@

TherI
lostat
spring
CID

Coil

spring

@

Note
As

previously
descnoed
heat

control
valv

1
is

welded
to
valve

shaft

@
at
exhaust
manifold
and

cannot
be

disassembled

To
install

reverse
the
removal

pro

cedure

INSPECTION

I
Run

engine
and

visually
check

counterweight
to

see
if
it

operates

properly

1
For
some
time
after

starling

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

3

When
heat

con
trol
valve
is
in
the

full

open
position
coun

terweight

moves
further
clockwise
exceeding
the
1

Snap
ring

2

Lock
bolt

3

Key

4

Counterweight

5
Thermostat

spring

6
Coil
spring

7

Heat
control
valve

8
Valve
shaft

9
Stove
gasket

10
Manifold
stove

11
Heat
shield

plate

Fig
EC
5

Exploded
view
of
E
F
E
stem

position
described
in
1

1
above

and

stops
again
coming
into
con
tact
with

stopper
pin

j

EC246

1

Counterweight

2
S

topper
pin

3
Heat
control
valve

Fig
EC
6

Operation
of
counterweight

when

engine
is
cold

EC246

1

Counterweight

2

Stopper
pin

3
Heat
control

valve

Fig
EC
7

Operation
of
counterw
ight

when
ngine
is
hot

EC
7
2

With

engine
stopped
visually

check
E
F
E

system
for
the

following

items

1
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

by
a
finger
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

DESCRIPTION

The

spark
tirnin
control

system

serves
to
control
the
distributor
vacu

um
advance
under

varying
travelling

conditions
so
as
to
reduce
HC
and

NOx
emissions

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

immediately
upon
deceleration
The

valve
is

designed
for
one

way
opera

tion
and
consists
of
a
one

way
umbrel

la
valve
and
sinlered
steel
fluidic

restrictor

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

Minimizes
exhaust

gas
tempera

lure
rise

2
Minimizes

horsepower
losses
re

suiting
from
air

injection
into
the

exhaust

system

3
Protects

pump
from
excessive

back

pressure

The
air

pump
relief
valve
is
installed

as
shown
in

Figure
EC

20

The

secondary
air
is

discharged

from
the
air

pump
relief
valve

to
the

dust
side
of
the
carburetor
air
cleaner

To
carburetor

air
cleaner

Secondary

air

To
carburetor

air

cleaner

J
erCOndary

r

r

EC294

Fig
EC
20
Air

pump
relief
valve
Emission
Control

System

Emargency
air
retial
valve

E
A
R
Valve

California
models

The

emergency
air
relief
valve
con

trols
the

quantity
of
secondary
air

fed

from
the
air

pump
according
to

load

condition
and
it

discharges
the
see

ondary
air
into
the

atmosphere
to

prevent
overheating
of
the

catalytic

converter

The

emergency
air
relief
valve
con

sists
of
a

diaphragm
a

spring
and

a

valve
which
is

coupled
to

diaphragm

1

Diaphragm

2

Val

3

Spring

4

Diaphragm
chamber

EC536

Fig
EC

21

mergency
air

relief
valve

OPERATION

As
mentioned

previously
there

are

two

types
of
Air

Injection
Systems

A
I

S
a

non
California

type
and
a
California

type
The
California
stand

ard

type
includes
a

system
which

controls

injection
of

secondary
air

so

as
to
assure

proper
function
of
the

catalytic
converter
and
a

system

which
controls
the

supply
of
second

ary
air
to

prevent
abnormal

tempera

tUfe
rise
in
the

catalytic
converter

The
A
I
S
consists
of
the

following

systems

L
A

system
which
allows

injection

of

secondary
air
into
the
exhaust

port

2
A

system
which

bypasses
sec

ondary
air

from
the
air

pump
relief

valve

to
the

carburetor
air

cleaner

during

high
speed
engine
operation

3
A

system
which

supplies
air

from

the
carburetor
air
cleaner

to
the
intake

manifold

by
means
of
the
anti

backfire

valve
so
as
to

prevent
after
fire

during

deceleration

4
A

system
which

controls

injection

of
the

secondary
air

by
means
of
the

air

control
valve

so
as
to
maintain
the

catalytic
converter
at
an

optimum

temperature
level
under

lightly
loaded

condi
tions

Califomia

type
only

5
A

system
which
controls
the

sup

ply
of

secondary
air

through
the
emer

gency
air

relief
vilve

io
pfevent
ab

normal

temperature
rise
of
the

cataly

tic

converter

California

type
only

A
I

S

operation
is

as
follows

I

I

t

1
r

9

I
Air

pump
6

Check
valve

I
0
L
2
Air

pump
air
deaner
7
Air

gallery
pipe

3
Air

relief
valve
8
Injection
non
e

r
4
Air
cleaner
9

Exhaust
manifold

5

Carburetor
10

Anti
backflIe
valve

EC179

Fig
EC
22
Non

California
type
A
I
S

EC
12

9
From
air

pump

l

h
1

Not
actuated

REMOVAL
AND

INSTALLATION

Air
p
mp
sir
cleaner

Remove
air
hose

then
detach
air

cleaner

from

hoodledge
Air
cleaner

element
and
Ii
r
deancr
lower

body
are

built
into
a
unit
construction

Replace

air
cleaner
clcl

nen
and

lower

body
as

an

assembly

J

J

tt
c

t
o

J

EC
323

Fig
EC
26
Replacing
oir
cleaner

element

Air

pum

Remove
air
hoses

from
air

pump

2
Loosen
air

pump
adjusting
bar

mounting
bolts
and
air

pump
mount

ing
bolts
then

remove
air

pump
drive

bell

3
Remove
air

pump
pulley

4
Remove
air

pump
from
bracket

Air
control
valve

California
models

l
Disconnect

air
hoses
and
a
vacu

um
hose
from
air
control
valve

2
Remove
air
con
trol
valve
from

bracket

E
A

R
valve
California
modela

Remove
vacuum

pipe
and
air

hose

and
dismount
E

A
R
valve
Emission
Control

System

o

jJ
To

Intake
mamfold

rF
vacuum

r

To
air

cleaner

From
air

pump

EC781

Fig
EC
27
Locotion

of
E
A
R
wive

Antl
backflravalve

Disconnect
air
hose
and
vacuum

hose
from
anti
backfire
valve

Check
valve

Disconnect
hose
and
remove
check

valve
from
air

gallery
pipe

Air

ganery
pIpe
andinJactlon

nozzles

It
is

very
difficult
to
remove
the
air

gallery
from
the
exhaust
manifold

without

bending
the

pipe
which
could

result
in
fractures
or

leakage
There

fore

removal
of

the
air

gallery
pipe

and

injection
nozzles
should
be
under

taken

only
when

they
are

damaged

I
Lubricate
around
the

connecting

portion
of
air

injection
nozzle
and
air

gallery
with

engine
oil

2
Hold
air

injection
nozzle

hexagon

head
with
a

wrench
and
unfasten
flare

screw

connecting
ait

gallery
to

injec

tion
nozzle
Remove
air

gallery

EC
14
To
intake

manifold

vaCUl
lm

r

Y

4
9
Gf

T

I
To

air
cleaner

I

Actuated

EC299

Fig
EC
25

Operation
of
air
control
value

Notes

a

Apply
engine
011
to
rews
several

times
during
above

work

b
Be
atreful
not
to

damage
other

parts

3
Unfasten
air

injection
nozzle

from

cylinder
head

applying
engine
oil

to
screwed

portion
several
times

4

Check
air

gallery
and
nozzle
for

fractures
or
leakage
Clean
air

injection

nozzle
with
a
wire
brush

5

At
time
of
installation
hold
air

injection
nozzle

hexagon
head
with

a

wrench
and

tighten
air

gallery
flange

screw
to
a

torque
of
5
0
to
5
9

kg
m

36
to
43
ft
lb

6
Check

cylinder
head
air

injection

nozzle
and
air

gallery
for
leaks
with

engine
running

Air

pump
relief
vslve

Loosen
carburetor
air
cleaner

mounting
sc
ews
and

remove
air

pump
relief
valve

InstallatIon

Install
in
the

reverse
order
of
reo

moval

DISASSEMBLY
AND

ASSEMBLY

Disassembly
of
air
pump

1
Remove
four

pulley
drive
bolts

and
remove

pulley
from
hub

2

Secure
air

pump
drive
hub
in

a

vise

as
shewn
in

Figure
EC

28
and

remove
four
end
cover
bolts

Air

pump

I

Operate
engine
until
it
reaches

normal

operating
temperature

2

Inspect
all
hose
hose
connec

tions
and
air

gallery
for
leaks
and

correct
if

necessary
before

checking

air

injection

pump

3
Check
air

injection
pump
belt

tension
and

adjust
to

specifications
if

necessary

4

Disconnect
air
supply
hose
at

check
valve

5

Disconnect
vacuum
hose
from
the

air

control
valve
California

type

only

6
Insert

open
pipe
end
of
Air

Pump

Test

Gauge

Adapter
STl9870000
in

air

supply
hose

Clamp
hose

securely

to

adapter
to

prevent
it
from

blowing

out
Position

adapter
and
test

lli
uge
so

that
air
blast
emitted

through
drilled

pipe
plug
will
be

harmlessly

dissipated

7
Install

a
tachometer

on

engine

With

engine
speed
at
2

600

rpm
ob

serve

pressure
produced
at

test

gauge

Air

pressure
should
be
100

mmHg

3

94

inHg
or
more

8
If
air

pressure
does

not
meet

above

specifications
proceed
as
fol

lows

I

Repeat
2
and
3

above

2
Disconnect
air

supply
hose
at

anti
backfire
valve

Plug
air

hose

open

ing
and

screw
with
a

clamp
Repeat

pressure
test

3
With

engine

speed
at
1

500

rpm

close
hole
of
test

gauge
with

finger
If

a

leaking
sound

is
heard
or

leaking
air

is
felt

by
ftnger
at
relief

valve
relief

valve
is

malfunctioning
Relief
valve

should

be

replaced
or

repaired

4

If
air

injection
pump
does
not

meet
minimum

requirement
of

pres

sure
test
it

should
be

replaced

Control
valve

The

following
procedures
are
reo

commended
for

checking
and
or
as

certaining
that
the
various

components

of
the
exhaust
emission
con
Irol

system

are

operating

properly

The

engine
and
all

components

must

be
at
normal

operating
tempera

tures
when
the

tests
are

performed

Prior

to

performing
any
extensive

diag

nosis

of
the
exhaust
control

system
it
Emission
Control

System

must
be
determined
that

the

engine
as

a
unit
is

functioning
properly

Check
valva

Warm

up
engine
thoroughly

2

Disconnect
hose

leading
to
check

valve
from
air

hose
COJUlector

3

Check
hose

opening
for

any
indi

cation
of
exhaust

gas
leaks
Ifleaks
are

detected

replace
check
valve

4

Race
the

engine

lightly
at
about

2
000

cpm
and
then

return
it
to

idling
VisuaDy
check
the
hose
for

any

indication
of
exhaust

gas
leaks
before

the

engine
returns
to

idling

speed
If

leaks
are
detected

replace
check
valve

EC310

Fig
EC
43

Checking
check
valve

Air

pump
raIle
valve

After

completing
inspection
of
air

pump
check
air

pump
relief
valve
in

the

following
steps

J

Disconnect
hoses

leading
to
check

valve
and
air
control

valve
from
air

hose

connector
and

install
blind

cap

to
the

connector

2
With

engine
running
at

about

3
000

rpm
under
no
load

place
your

hand
on
the
air

outlet
of
air

pump

relief
valve
to
check
for

discharged
air

If
no
air

is
felt

replace
the
air

pump

relief

valve

EC311

Fig
EC
44

Checking
air

pump
relief

valve

EC

18
Air
control
valve

C
U
ornla
models

I
Warm

up
engine
thoroughly

2
Before

checking
air
control

valve

check
all
hoses

for
loose
connection

leaks
etc
and

repair
or

correct
if

necessary

3

With

engine
idling
disconnect
the

outlet
side
hose
of

the
air
control

valve
and

place

your
hand
on
the
air

hose
outlet
to
check
for
air
If
no
air
is

felt

replace
the
air

control
valve

4

Pull
vacuum
hose
off
from
air

con
trol
valve
If

discharge
of
air
from

air
hose

stops
the
air
con
trol
valve

is

normaL
If

discharge
is
still
felt

replace

the
valve

Plug
up
the

removed

vacuum
hose

to

stabilize

engine
running

EC312

Fig
EC
45

Checking
air
control
valve

Emarsancy
air
rella
valve

E
A
R
Valve

lCalHornla
models

L
Warm

up
engine
thoroughly

2

Before

checking
air

control
valve

check
all
hoses
for
loose
connection

leaks
etc
and

repair
or
correct
if

necessary

3
Race

engine
approximately

2
000

rpm
under
no
load
Place

your

hand
on
air

outlet
of
E

A
R
valve
to

check
for

presence
of

discharged
air
If

no
air

is
felt

E
A

R
valve
is
normal

4

Disconnect
vacuum
hose
from

B
A

R
valve
as
shown
in

Figure
EC

46

Race

engine
approximately
2
000

rpm
under
no
load
Place

your
hand

on
air
outlet
of
E
A
R
valve
to
check

for

presence
of

discharged
air
If
air
is

felt

E
A
R
valve
is
normaL

5

If
E
A
R

valve
does
not
function

properly
at
above

steps

replace
E
A
R

valve

To

air

pump

I

ET267

Fig
EC
46

Cheeking
E
A
R
volve

Anti
backfire

valve
A
valve

Warm

up
engine

thoroughly

2
Disconnect
hose

from
air

cleaner

and

place
a

finger
near
the
outlet

3
Run

engine
at
about
3

000

rpin

under
no
load
then

quickly
cetum
it

to

idling
If

you
feel
a

pull
or
suction

force
on

your
finger
the
anti

backfire

valve

is

functioning
normally
If
no

suction
is
felt

replace
the

anti
backflre

valve

Fig
EC
47
Checking
anti

backfire
valve
1
t
D

I
Y1

VI
I

ID
4

JO
0

2
E

C
R
control
valve

3

E
C
R

passage

4
Intake
manifold

5

Thermal
vacuum
valve

6
E
C
R
tube

7
Exhaust

manifold
Emission
Control

System

tXHAUST
GAS

RECIRCULATION

CONTROL
SYSTEM

E

G
R

DESCRIPTION

In
the

exhaust

gas
recirculation

system
a

part
of
the
exhaust

gas
is

returned
to
the

combustion
chamber

to
lower
the

spark
flame

temperature

during
combustion
This
results
in
a

reduction

of
the

nitrogen
oxide

con

ten
t

in
the
exhaust

gas

The
exhaust

gas
recirculation

sys

tem
consists

of
an
E
G
R

passage

E
G
R

con
trol
valve
thermal

vacuum

volve
E
G
R

tube
and
hose
A

warn

@
I
ing
system
which
indicates
when
the

E
G
R

control

system
must
be

in

spected
is
also
installed
in

all
620

models

except
those
bound
for

Coli

fornia
and
Canada

When
the
E

G
R
con
trol

valve
is

open
some
of

the
exhaust

gas
is

led

from
the

exhaust
manifold
to
the

E
G

R
chamber

through
the
E
G

R

passage
The
exhaust

gas
is

then
con

trolled
in

quantity
by
the
E
G
R

valve

and
is
introduced
into
the

intake

manifold

Open
c1ose

operation
of
the
E
G
R

control
valve

is
controlled

by
the

thermal

vacuum
valve
which

opera
tes

on

carburetor
vacuum
and

engine
cool

ant

temperature

EC349

Fig
EC
4
Exhaust
Gas
Recirculation

system
E
G
R

E
G
R

system
operating
Thermal
Intake
manifold
E
G
R

Remarks

E
G
R

water

temperature
oC
OF
vacuum
valve
vacuum
control
valve

Below
570C
135OF
Close
Close

Non
california

Above

MfT
models

only
Idling

Not
Above
57

to
630C

Open
70

mmHg
Close

actuated
135
to
145OF
76

inHg

California
models

Below

and
N
on
Fullthrollle

f

alifomia

AfT

Above
57
to
6
oC
models

Actua
ted

Open
Above
50

mmHg

Open

135
to
145OF
1
97

inHg

EC
19
OPERATION

Operation
of
E
G
R

system
is
as

shown
below