1977 DATSUN PICK-UP ECO

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

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

Floor
temparature
warning

lamp

Refer

to

Figure
EC
74

for
the

loca

tion
of
this

part

L

1t

1

RAt

Fig
EC
74
Location
of
floor

temperature
warning
lamp

INSTALLATION

To
install
reverse
the
order
of

rem
ovaL

INSPECTION

Floor
warning
temperature

system

Apply
parking
brake
Shift

gears

into
Neutral
foI
manual
transmission

and
Neutral
or
Park
for
automatic

transmission

1
Ensure
that
floor

temperature

warning

lamp
lights
when

ignition

switch
is
iumed

to
the
S

position

If

not
check

lamp
for
burned

bulbs

Replace
bulb
if
bulb
is
burned
out

If

bulb
is

not
burned
trace
wire
s

back
to

ignition
switch

Repair
or

replace
if

necessary

2
Be

sure
that
floor

temperature
is

cool
below
800C

1760Fj
before

carrying
out
the

following
procedure

I
Remove
rearseat

2

Ignition
switch
is

turned
to
the

IG

position

3
Ensure
that
floor

temperature

warning
lamp
goes
out

4
Heat

surrounding
areas
of
floor

temperature
sensing
switch
with
a

proper
heater
to
ensure
that
floor

temperature
warning
lamp
glows
when

floor
is
heated

to
the

specifications
as

shown
in
the
table
below
Emission
Control

System

Temperature

sensing
switch

Contact
close
Temperature

warning
lamp

Off

Contact
open
On

Note

Avoid

heating
floor

tempera

ture

sensing
switch

directly

If

lamp
does

not
glow
check
floor

temperature
sensing
switch
connector

for

continuity
with

a
circuit
tester

If

continuity
should
exist
after

heated

surrounding
areas
of
floor
tem

perature
sensing
switch

replace
tem

perature
sensing
switch

If
con

tinuity
does

not
exist

trace

the

wiring
back
to

relay
or
check
the

following
step
3

Repair
or

replace

wire
s
if

necessary

Note
The

floor

temperature
sensing

switch

may
be
heated

through
the

floor

by
a

proper
heater

3
Turn

ignition
switch
to
the

IG

position
and
disconnect
floor

temper

ature

sensing
connector
The

lamp

should
remain

on
If

not
check
floor

temperature
relay
for

continuity
with

2
00

r
I

141

J

To
floor

temperatwe

warning
lamp

2
From

S

position

3
From

IG

position

4

From

ignition
switch

5
To
floor

temperature

sensing
switch
O

When
floor

temperature

warning
lamp
lights

Check
floor

temperature
warning

lamp

1

Open
or

shorj
circuit
in

wiring

harness

2

Check
fuel

system
with

regard
to

the

following
items

Refer
to

Inspec

lion
of
Fuel

System

EC
29
Floor

temperature

Below
1050C
221
OF

Above

1050C
221
OF

a
circuit

tester

Referring
to
the

following
floor

temperature
relay
if

relay
is
normal

trace
wire
s

back
to

ignition
switch

Repair
faulty
wiring

Floor

temperature
relay

When

checking
floor

temperature

relay
for
unit

remove
it
and

proceed

as
follows

1

Check
for

continuity
between

@

and

ID
Continuity
should
exist

Check
for

continuity
between

CD

and@
Continuity
should
exist

Check
for

continuity
between

CD

and

@
Continuity
should
not

exist

2

Apply
a
12

volt
doc
across

@
and

ID
to

ensure
that

continuity
exists

between

CD
and

@
and
that

con
ti

nuity
does

not
between

CD
and

@
If

test
results
dn

not

satisfy
the
above

replace
the

floor

temperature
relay

EC344

Fig
EC
75

Checking
floor
temperature
relay

1
Float
level

2
Choke

3

Normal
fuel

supply
system
Prima

ry
and

secondary

4
Accelerator

pump

5
Power
valve

6
B
C
D
D

7
Fuel
strainer

8
Air
cleaner

J

1
Fuel
tank

2

Fuel
f1l1er

cap
with

vacuum

relief
valve

3

Liquid
vapor

separator

4

Vapor
vent
line

5
Vacuum

signalUne

As
the
throttle
valve

opens
and

vehicle

speed
increases

vacuum

pres

sure
in

the
vacuum

signal
line
forces

rHL
JL

I

EC785

INSPECTION

FUEL
TANK

VAPOR

LIQUID
SEPARATOR

AND

VAPOR
VENT
LINE

I

Check
all
hoses
and
fuel

tank

mler

cap

2
Disconnect
the

vapor
vent

line

connecting
carbon
canister
to

vapor

liquid
separator

3
Connect
a
3

way
connector

a
Emission

Control

System

Close
at

idling

Open
at
rest

i

J

17
f

Fuel

vapor

6
Canister
purge
line

7
Throttle
valv

8

Engine

9
Carbon
canister

10
Activated
carbon

11

Screen
12
Filter

13

Purge
control
valve

14

Spring

15

Diaphragm

16
Fixed

orifice
i

j

EC784

Fig
EC
77

Evaporative
emu
ion
control

sy
tem

Fuel

vapor
flow
when

engine
i6

at
red
or

idling

the

purge
control
valve
to

open
and

admits
an

orifice
to
intake
manifold

and
fuel

vapor
is

then
drawn
into
the

I

J

o
I

Fuel

vapor

Fresh
air
intake

manifold

through
the
canister

purge
line
See

Figure
EC
7B

Fig
EC
78

Evaporative
emiuion
control

system

Fuel

vapor
flow
when

engine
i

running

manometer
and
a
cock
or
an

equiva

lent
3

way

charge
cock
to

the
end
of

the

vent
line

4

Supply
fresh
air
into

the

vapor

vent
line

through
the
cock
little

by

little
until

pressure
becomes
368

mrnH20

14
5
inH20

5
Shut
the
cock

completely
and

leave
it

unattended

6
After
2
5
minutes

measure
the

height
of
the

liquid
in
the

manometer

7

Variation
of

height
should
remain

EC
31
with
25
mmH20
0
98
inH20

8
When
filler

cap
does
not
close

completely
the

height
should

drop
to

zero
in

a
short
time

9
I
f

the

height
does
not

drop
to

zero
in

a
short
time
when
filler

cap
is

removed
it
is

the
cause
of
a

stuffy

hose

Note
In

case
the

vent
line
is

stuffy

the

breathing
in
fuel
tank
is
not

thoroughly
made
thus

causing
in

Condition
Engine
Electrical

System

Probable
cause

Starting
motor

cranks

slowly
Dirty
or
worn
commutator

Armature
rubs

field
coil

Damaged
solenoid
switch

Starting
motor

operates
but
does

not
crank

engine
Worn

pinion

Locked

pinion
guide

Worn

ring

gear

Starting
motor
will

not

disengage
even
if

ignition
switch
is

turned
off
Damaged
solenoid
switch

Damaged

gear
teeth

The

charging
circuit
consists

of
the

battery
alternator

regulator
and

necessary

wiring
to
connect
these

parts
The

purpose
of
this

system
is
to

convert
mechanical

energy
from
the

engine
into

electrical

energy
which

is

used
to

operate
all

electrically

operat

ed
units

and
to

keep
the

battery
fully

charged

When
the

ignition
switch
is

set
to

ON
current
flows
from
the

battery

to

ground
through
the

ignition
switch

voltage
regulator
IG
terminal

primary

side
contact

point
PI

movable

contact

point
P2

voltage

regulator

IF

terminal
alternator
IF
terminal

rotor

field
coil
and
alternator

E

terminal

as
shown
in

Figure
EE

23

by

full
line

arrow
marks
Then
the

rotor

in

the

alternator
is
excited

On
the

other
hand

current
flows

from
the

battery
to

ground

through
the

ignition

switch

warning

lamp
voltage
regula

tor
L

terminal

lamp
side
contact

point
P4

movable

contact

point

P5
and

voltage
regulator
E
termi

nal
as
shown

by
dotted

line
arrow
CHARGING
CIRCUIT

marks
Then

the

warning
lamp
lights

When
the
alternator

begins
to

op

erate
three

phase

alternating
current
is

induced
in

the

stator
armature
coil

This

alternating
current
is
rectified

by

the

positive
and

negative
silicon

diodes
The
rectified

direct
current

output
reaches
the
alternator
A

and

E

terminals

On
the
other
hand
the
neutral

point
voltage
reaches
N
and
E

terminals

nearly
a
half
of

the

output

voltage
and
current
flows
from

voltage
regulator
N
terminal
to
E

terminal
or

ground
through
the
coil

VCI
as
shown
in

Figure
EE
24

by

the
dotted
line
arrow
marks
Then
the

coil
VCI
is
excited
and
the

movable
contact

point
IPS
comes

into
contact
with

voltage
winding
side

contact

point
P6
This
action
causes

to
turn
off

the

warning
lamp
and

complete
the

voltage
winding
circuit

as
shown

by
the
full

line
arrow
marks

When
the
alternator

speed
is
in

creased
or
the

voltage
starts
to
rise

excessively
the
movable
contact

point

EE
12
Corrective
action

Clean
and

repair

Replace
assembly

Repair
or

replace

Replace

Repair

Replace

Repair
or

replace

Replace
damaged

gear

P2
is

separated
from

the

primary

side
contact
PI

by
the

magnetic

force

of
coil
VC2
Therefore

registor
RI
is

applied
into
the
rotor

circuit

and

output
voltage
is
decreased

AJ

the

output
voltage
is
decreased

the

movable
contact

point
P2
and

primary
side
contact
Pin

comes
into

contact
once

again
and

the
alternator

voltage
increases

Thus
the

rapid

vibration
of
the
movable

contact

point

IPl

maintains
an
alternator

output

voltage
constant

When
the
alternator

speed
is

further

increased
or
the

voltage
starts
to
rise

excessively
the

movable
contact

point

P2
comes

into
contact
with

secondllJ
side
contact

point
P3

Then
the
rotor
current
is

shut
off
and

alternator

output
voltage
is

decreased

immediately
This

action
causes

movable
contact
n
to

separate

from

secondary
contact
P3
Thus

the

rapid
vibration
of

the
movable

contact

point
P2

or

breaking
and

completing
the

rotor
circuit
maintains

an
alternator

output
voltage
constant

Engine
Electrical

System

I

Start

engine

2
Rotate

engine
at
2
500

rpm
for
several

minutes

Mter

racing
for

several
minutes

ammeter

reading

below
SA
After

racing
for

several
minutes

ammeter

reading
over
5

A

Fully

charged
battery
available

I

Replace
with

fully
charged

battery

2
Check

to
see
if
current
falls

below
SA
Fully
charged

battery
not
available

I
Connect
a

0
25
ohm

resistor
in
series

Current
falls
below

SA

Current
does

not
fall
below

SA

Recharge
battery
and

see
if

current
falls

below

SA

Reduce

engine
speed
to

idling
and
then

raise
it

to
2
500

rpm
while

observing
needle
of
voltmeter

Needle
of

voltmeter
held
within
limits

shown
in

the
below

table

Regulator

functioning
properly
Needle
of
voltme
ter
ou
t
of
limits
shown
in

the

following
chart

Adjust
or

replace
regulator

Regulator
type
TLI

Z
85C

Temperature
Oc
OF

Voltage
V
speed

c

Voltage

may
be

approximately

0
3
V

higher
than
rated
for
two
to

three
minutes
after

engine
is

start

ed
or
more

specifically
when

regu

lator
becomes
self
heated

Measure

ments
should

then
be
made

within

one
minute

after

starting
engine
or

when

regulator
is

cold

d
The

regulator
is

of
a

temperature

compensating
type
Before
meas

uring
voltage
be

sure
to
measure

surrounding
temperature
and
cor

rect

measurements

according
to
the

table
at
left
10

14

0

32

10

50

20
68

30
86

40
104
14
75
to
15

75

14
60
to
15
60

14
45
to
1545

14

30
to

15
30

14

15
to
15
15

14

00
to

15
00

Notes

3
Do

not
measure

voltage
immediate

ly
after

driving
Do
this
while
regulator
is
cold

b

To
measure

voltage
raise

engine

speed
gradually
from

idling
to

rated

EE
22

NON
CALIFORNIA
MODELS
Engine
Electrical

System

IGNITION
CIRCUIT

CONTENTS

EE
26

CALIFORNIA
MODELS
EE
2B

NON

CALIFORNIA
MODELS

The

ignition
circuit
consists

of
the

ignition
switch
coil

distributor

wiring
spark
plugs
and

battery

The
circuit

is

equipped
with
a

resistor

During
cranking
electrical

current

bypasses
the
resistor

thereby

connecting
the

ignition
coil

directly
to

battery
This

provides
full

battery

voltage
available
at
coil
and

keeps

ignition

voltage
as

high
as

possible

The

low

voltage
current
is

supplied

by
the

battery
or

alternator
and

flows

through
the

primary
circuit

It
consists

of
the

ignition
switch
resistor

primary
winding
of
the

ignition
coil

distributor
contact

points
condenser

and
all

connecting
low
tension

wiring

The

high

voltage
current
is

pro

duced

by
the

ignition
coil

and
flows

through
the

secondary
circuit
result

ing
in

high

voltage
spark
between
the

electrodes
of

the

spark
plugs
in

engine

cylinders
This
circuit
contains

the

0
cl

Battery

Ignition
coil
secondary
winding
of

the

ignition
coil

high
tension

wiring
distributor
rotor

and

cap

When
the

ignition
switch
is

turned

on
and
the

distributor
contact

points

are
closed

the

primary
current

flows

through
the

primary
winding
of
the

coil
and

through
the

contact

points
to

ground

When
the

contact

points
are

opened

by
the

revolving
distributor
earn
the

magnetic
field
built

up
in
the

primary

winding
of
the

coil
moves

through
the

secondary
winding
of
the

coil

inducing

high
voltage
The

high

voltage
is

produced

every
time

the

contact

points

open
The

high
voltage
current

flows

through
the

high
tension
wire

to
the
distributor

cap
Then
the
rotor

distributes
the
current
to

one
of
the

spark

plug
terminals
in
the
distributor

Re5istor

To

starter

Secondary

winding

Cap

Breaker

point

f

Distributor

EE
26
cap

Then
the

spark
obtains
while
the

high
voltage
current

jumps
the

gap

between
the

insulated
electrode
and

the

ground
side
electrode
of
the

spark

plug
This

process
is

repeated
for
each

power
stroke
of

the

engine

The
distributor
contact

point
and

spark
plugs
should
be

inspected
clean

ed

and

regapped
at

tune

up
They

should
also
be

replaced
periodically
as

specified
in

the
Maintenance

Sched

ule
In

addition

apply
grease
NLGl

consistency
No
I

containing

MoS2
or

equivalent
to
distributor

shaft
and

grease
MIL
G
l0924B

containing

MoS2
or

equivalent
to
cam
as
reo

quired

The
remainder

of
the

ignition

component

parts
should
be

inspected

for

only
their

operation
tightness
of

electrical
terminals
and

wiring
con

dition

The

ignition
circuit
is
shown
below

IR

IB

I

is
21

J
g

Rotor

head

EE060

Fig
EE

53

Ignition
ydem
circuit

diagram