1977 DATSUN PICK-UP Service Manual

DESCRIPTION

FUEL

PUMP
TESTING

STATIC
PRESSURE
TEST

CAPACITY
TEST

DESCRIPTION

The
fuel

pump
transfers
fuel
from

the
tank
to
the
carburetor
in
sufficient

quantity
to
meet
the

engine
require

ments
at

any
speed
or

load

The
fuel

pump
is
a

pulsating
type

designed
for

easy
maintenance
It

con

sists
of
a

body
a

rocker
arm

assembly

a

fuel

diaphragm
a
fuel

diaphragm

spring
seal
inlet
and
outlet

valves

Figure
EF
19

shows
a
cross
sectional

view
of
the

pump

The
fuel

diaphragm
consists

of

specially
treated
rubber
which
is

not

affected

by

gasoline
and
held
in

place

by
two

metal
discs
and

a

pull
rod

FUEL

PUMP

TESTING

A
fuel

pump
is

operating

properly

when
its

pressure
is

within

specifica

tions

and
its

capacity
is

equal
to
the

engine
s

requirements
at
all

speeds

Pressure
and

capacity
must
be
deter

mined

by
two
tests
while
the

pump
is

still

mounted
on
the

engine
Be
sure

there
is
fuel
in

the
tank
when

carrying

out
the
tests
Engine
Fuel

MECHANICAL
FUEL
PUMP

CONTENTS

EF
9

EF
9

EF
9

EF
10
REMOVAL
AND
DISASSEMBLY

INSPECTION

ASSEMBL
Y
EF

10

EF
10

EF

11

1

1

Outlet
valve

2

Diaphragm

3

Diaphragm
spring

4
Inlet
valve

S
Rocker
ann
EF006

Fig
EF
19
Schematic
view

of
fuel
pump

STATIC
PRESSURE
TEST

The
static

pressure
test
should
be

made
as
follows

I
Disconnect
fuel
line
between
car

buretor
and
fuel

pump

2
Connect
a
rubber
hose
to
each

open
end
of
a
T
connector
and
con

nect
this
connector
hose

assembly
be

tween
carburetor
and
fuel

pump
Note
Locate
this
T
connector
as

close
to

carburetor
as

possible

3
Connect
a

suitable

pressure
gauge

to

the

opening
of
T
connector
and

fasten
hose
between
carburetor
and

T
connector
with

a

clip
securely

EF
9

4

Run
the

engine
at

varying
speeds

5

The

pressure
gauge
indicates

static
fuel

pressure
in
the
line

The

gauge
reading
should
be

within
the

following
range

0
21
to
0

27

kg
em2

3
0

to
3

8

psi

Note
If

the
fuel
in
carburetor
float

chamber
has
run
out

and

engine
has

stopped
clip
and

pour
fuel

into

carburetor
Fasten

clip
secure

ly
and

repe
1
static

pressure
test

Pressure
below
the
lower
limit
indi

cates
extreme
wear
on
one

part
or

a

small
amount
of
wear
on
each

working

part
It

also
indicates

ruptured
dia

phragm
worn

warped
dirty
or

gum

ming
valves
and
seats
or
a
weak

diaphragm
return

spring
Pressure

above
the

upper
limit
indicates
an

excessively
strong
tension
of
dia

phragm
return

spring
or
a

diaphragm

that
is
too

tight
Both
of
these
condi

tions

require
the
removal
of

pump

assembly
for

replacement
or

repair

CAPACITY
TEST

The

capacity
test
is

made

only

when
static

pressure
is
within
the

specifications
To

make
this
test

pro

ceed

as
follows

1

Disconnect

pressure
gauge
from

T
connector
and
in
its
vacant

place

install
a

suitable
container

as
a
fuel

sump

2
Run

engine
at
1

000

rpm

3
The

pump
should

deliver
1
000

cc

2
11

US

pt
of
fuel
in

one
minute
or

less

If
little

or
no
fuel
flows
from
the

open
end
of

pipe
it
is
an

indication

that
fuel
line
is

clogged
or

pump
is

malfunctioning

REMOVAL
AND

DISASSEMBLY

Remove
fuel

pump
assembly
by

unscrewing
two

mounting
nuts
and

disassemble
in

the

following
order

1

Separate

upper
body
and
lower

body
by

unscrewing
body
set
screws
Engine
Fuel

2

Take
off

cap
and

cap
gasket
by

removing
cap
screws

3
Unscrew
elbow

and
connector

4
Take
off
valve

retainer

by
un

screwing
two
retainer

screws
and
re

move
two
valves

5
To
remove

diaphragm

press

down
its

center

against
spring
force

With

diaphragm
pressed
down

tilt
it

until
the
end
of

pull
rod
touches
the

inne

wall
of

body
Then
release

diaphragm
to
unhook

push
rod
Be

careful

during
this

operation
not
to

damage
diaphragm
or
oil
se
L

i
J

EFOO7

Fig
EF

20
Remouing
pull
rod

6
Drive
rocker
arm

pin
out
with
a

press
or
hammer

8

o

6

7

8

@

INSPECTION

I

Check

upper
body
and
lower

body
for
cracks

EF
10
I
fuel

pump
cap

2

Cap
gasket

3
Valve

packing

4

fuel

pump
val
e

assembly

S
Valve
retainer

6

Diaphragm
assembly

7

Diaphragm
spring

8
PuRro

9

Lower
body
seal

washer

10
Lower
body
seal

11
Inkl
connector

12
Outlet
connector

13
Rocker
arm

spring

14
Rocker
arm

I
S
Rocker

artyl
side

pin

16
Fuel
pump
packing

17

Spacer
fuel

pump

fo
cylinder
block

EF510

Fig
EF
21
Slruc
ure
of
fuel

pump

2
Check

valve
assembly
for
wear
on

valve
and
valve

spring
Blow
valve

assembly
with
brea
th
to
examine
its

function

3
Check

diaphragm
for

small
holes

carcks
or
wear

4

Check

rocker
arm
for
wear
at
the

mating
portion
with

camshaft

5

Check
rocker
arm

pin
for
wear
A

worn

pin
may
cause
oil

leakage

6
Check
all

other

components
for

any
abnormalities
and

replace
if
neces

sary

DESCRIPTION

INSPECTION

REMOVAL
AND

INSTALLATION

DESCRIPTION

The
electric
fuel

pump
is

adopted

on
air

conditioner

equipped
models
Engine
Fuel

ASSEMBLY

Reverse

the
order
of

disassembly

Closely
observe
the

following
instruc

tions

L

Use
new

gaskets

2

Lubricate
rocker
ann
rocker
arm

link
and

rocker
arm

pin
before
installa

tion
3

To
test
the

function

proceed
as

follows

Position
fuel

pump
assembly
about

I

meter
3
3
ft

above
fuel
level
of

fuel

strainer
and
connect
a

pipe
from

strainer
to
fuel

pump

Operate
rocker

arm
by
hand
If

fuel

is

drawn

up
soon
after
rocker
arm
is

released

fuel

pump
is

functioning

properly

ELECTRIC
FUEL
PUMP

CONTENTS

EF
11

EF
11

EF
12
DISASSEMBL
Y

ASSEMBL
Y

TROUBLE

DIAGNOSES
AND

CORRECTIONS
EF
12

EF
12

The
silicon
transistor

type
fuel

pump

consists
of

a
transistor
diodes
a

sole

I
Tr

lOsistor

6
Ou
tIet
valve

2

Plunger

7
Return

spring

3

Diaphragm

8
Filter

4

Diode

9

Magnet

5

Magnet
coil

10
Inlet
valve

INSPECTION

I
Disconnect
fuel
hose
at

pump

outlet

2

Connect

a
suitable
hose

approxi

mately
6

mm
0

24
in
inner

dia

meter
to

pump
outlet
ev
J

J

Note
If
diameter
is
too
small
the

following

proper
delivery

capacity

cannot
be
obtained
even
if

pump

functions

properly

EF
11
EF
13

noid
a

pump
mechanism
and
filter

parts

I
T
nsistor

2

Re
ist
f
I

3
Dinde

4

Signal
coil

5
Main
coil

6
Resistor
3

7
Zener
dlOdl

8

Resistor
2

EF719

Fig
EF
22
Construction

of
electric

fuel

pump

3

With
hose
outlet
in
a

higher
posi

tion

than

pump

operate
pump
and

check

delivery
capacity
for
more
than

15

seconds

4

The

capacity
should
be
I
400

cc

854
co
in
in
one
minute
or
less

If
no

gasoline
or

only
a

little
flows

from

open
end
of

pipe
with

pump

operated
or
if

pump
does

not
work

perform
the

following
diagnosis

Notes

3
Do
not

connect
battery
in
reverse

polarity
which
if
left
for
a

long

time
would

damage
transitor

circuit
and
disable

pump
Engine
Fuel

b
Do
not
let
fall

pump
as
it

may

damage
electronic

components

c
Do
not

apply
overvoitage
max

l
8Y

Overvoltage
starting

by

quick
charge
or

tage
running

would
deteriorate
or

damage
elec

tronic

components

Fuel

pressure
maximum

0
32

kg
cm
4
6

psi

REMOVAL
AND
INSTALLATION

Flom
fuel
tank

Electric
fuel

pump
is
installed
on

bracket
with
two
bolts
This
bracket
is

located
on
R
H
side
member

adjacent

to
fuel
tank

I
Remove
inlet
hose
from
fuel

pump
Also
remove
outlet
hose
run

ning
to

engine
Receive
fuel

remaining

in
fuel
hose
in
a
suitable
container

2
Disconnect
harness
at

connector

3
Remove
bolts

securing
fuel

pump

to
bracket
and
detach
fuel

pump

4

Installation
is

the
reverse
order
of

removal

9

@

1
Cover

2

Magnet

3
Cover

gasket

4
Filter

5
Gasket

6

Spring
retainer

7
Washer
8
O

ring

9
Inlet
valve

10
Retutn

PIing

11
Plunger

12

Plunger
cylinder

13

Body
To
carburetor

1
Elecuic
fuel

pump

2

Mounting
bracket

3
Fuel
mter

EF72D

Fig
EF
23
Electric
fuel

pump

DISASSEMBLY

Do
not
disassemble
unless

pump
is

faulty

I
Remove

cover
with
wrench
and

take
out
cover
gasket
magnet
and

filter
from

pump
body

2
When

removing
plunger
take
out

spring
retainer
from

plunger
tube

3
Then
take
out
washer
O

ring

inlet
valve
return

spring
and

plunger

from
tube

Note
Do
not
disassemble
electronic

components
If

n

replace

with
new
ones

6

EF721

Fig
EF
24

Exploded
view

of
electric
fuel

pump

EF
12
ASSEMBLY

I

Before

assembly
clean
all

parts

with

gasoline
and

compressed
air

com

pletely

Notes

a
If

gask
t

an
d
fdterare

faulty
r

place

b
Clean

magnet
and
cover
for
fault

c
Take
care
not
to
defonn
thin
tube

d
Assemble

plunger
return

spring

inlet
valve
O

ring
washer
and
set

spring
retainer
in
that
order

e

Assemble
filter

gasket
and
cover

with

f

Tighten
cover
with
wrench
to
the

stopper

If

component
parts
are

dirty
after

disassembly
clean
as
follows

Wash
fIlter
and
strainer
with
clean

gasoline
and
blow
with

compressed

air
When

cleaning
parts
check

fllter
for
fault
If

faulty
replace

Wash

plunger
plunger
cylinder
and

inlet
valve
with
clean

gasoline
and

blow
dust
off

with

compressed
air

2
Check

c
v
m
lI

parts
for
wear

or

damage

If

they
are
found

faulty

replace

them

3

Insert

plunger
assembly
into

plunger
cylinder
of

body
and

apply

electric
current
to
it

Move
the

assembly

up
and
down

If
the

assembly
does
not
move
it

shows

that
the
electric

uuit
is

faulty

and
it
must
be

replaced

Engine
Fuel

TROUBLE
DIAGNOSES
AND
CORRECTIONS

Condition

Fuel

pump
fails
to

operate

Fuel

pump
fails
to

discharge
sufficient

flow

Insufficient
fuel

discharge
during

high
speed
travelling

Low
float
level

at

idling

Fuel

pump
is
actuated

more

frequently
than

under
normal
condi

tion

Rattling
noise
Probable
cause

Terminals
or
connections
loose

Rust
on
terminals
or

grounding
metal

Frozen

liquid
in

plunger
or

pump

Clogged
filter

Insufficient
fuel

Air
in

fuel
hose

through
connections

Hose
necked
down
or
bent

Fuel
tank
breather
tube
bent
or
necked

down

Weakened
return

spring

Air
sucked

through
connection
fuel
hose

and
fuel

pump
joint

Fuel
hose
on
suction
side
bent

Clogged
fIlter

Mounting
bolts
loose

EF
13
Corrective
action

Retighten

Clean

Clean

plunger
assembly

Replace
pump
if

plunger
is

stuck
or
seized

Clean

pump
interior
Clean
and

if

necessary

replace
fIlter

Replenish

Apply
a

coating
of
end
sealing

compound
to

connections
and

retighten

Check
and
correct

Check
and
correct

Replace

Apply
a

coating
of
end

sealing
compound
to

connection
and

retighten

Check
and
correct

Clean
or

replace
fIlter

Retighten

Engine
Fuel

CARBURETOR

CONTENTS

DESCRIPTION

EF
14
CHOKE
UNLOADER

EF
23

STRUCTURE
AND

OPERATION
EF
14

ELECTRIC
AUTOMATIC
CHOKE
EF

24

PRIMARY
SYSTEM

EF
15
INTERLOCK
OPENING
OF
PRIMARY
AND

SECONDARY

SYSTEM
EF
16
SECONDARY
THROTTLE
VALVE

EF
24

ANTI
DIESELING

SYSTEM
EF
17
DASH
POT

EF
25

FLOAT

SYSTEM
EF
18
ACCELERATING
PUMP

EF

25

BOOST
CONTROLLED

DECELERATION
ANTI
DIESELING
SOLENOID
VALVE

EF

25

DEVICE

B
C
D
D
EF
1B

B
C

D
D
CIRCUIT
WITH

FUNCTION

ELECTRIC

AUTOMATIC

CHOKE
EF
20
TEST

CONNECTOR

EF
25

DASH
POT
SYSTEM
EF
20

ALTITUDE
COMPENSATOR

ALTITUDE

COMPENSATOR

California
modelsl
EF

29

California

models

EF
20
MAJOR
SERVICE

OPERATION
EF

29

ADJUSTMENT
AND

INSPECTION
EF
21
REMOVAL
EF
29

CARBURETOR
IDLE
RPM
AND
DISASSEMBLY
AND
ASSEMBLY
EF

30

MIXTURE

RATIO

EF
21
CLEANING
AND

INSPECTION
EF
34

FUEL
LEVEL

EF
22
SERVICE
DATA
AND

SPECIFICATIONS
EF

35

FAST

IDLE

EF
22
TROU8LE

DIAGNOSES
AND

VACUUM
BREAK

EF
23
CORRECTIONS
EF

36

DESCRIPTION

The

carburetors
are
of

down
draft

two

barrel

types
which

produce
the

optimum
air
fuel
mixture
under

all

operating
conditions

They
present
several

distinct

features
of

importance
to
the

vehicle

owners

A

summary
of
the

features
is

as

follows

1
A

slow
economizer
to

make
a

smooth

connection
with

acceleration

or
deceleration

during
light
load

run

ning

It

also

assures
stable
low

speed

performance

2

An
idle

limiter
to

reduce
harmful

exhaust
emissions
to

a
minimum
3
A

B
C
D

D

device
for

reducing

hydrocarbon
H
C
emissions

4

An

electric
automatic

choke
to

facilitate
cold

starting
and
to
reduce

exhaust
emissions

5

An
anti

dieseling
solenoid
to

eliminate

dieseling
run

on

6
A

power
valve

or
vacuum
actu

ated
booster
to

ensure

smooth

high

speed
operation

7

The

carburetor

comes

equipped

with
dash

pot
which
ensures

smooth

deceleration

without

engine
stall

under

all

operating
conditions

8

The
hand

operated
altitude

com

pensator
is

installed
in
the
California

models

EF
14
STRUCTURE
AND

OPERATION

These

carburetors
consist
of

a

primary
system
for

normal

running

and
a

secondary

system
for
full
load

running

A

float

system
common
to
both

primary
and

secondary
systems
a
se

condary
switch

over
mechanism

an

accelerating
mechanism
etc
are

also

attached

An

anti

dieseling
solenoid
valve

and

a

power
valve
mechanism
are
also

installed

The
hand

operated
altitude

com

pensator
corrects
air

fuel
mixture

to

an

optimum
ratio

tZrJ

I
Fuel

nipple

2
Fuel
filter

3

Needle

4
Float

S

Primary
main

jet

6
Idle

adjust
screw

7
I
die
hole

8

Primary

bypass
hole

9

Primary
throttle
valve

10

Primary
altitude

compensator

pipe
California
models

11

Secondary
altitude

compensator

pipe
California
models
Engine
Fuel

jli@

I

12
Air
bleed

13
Primary
slow

jet

14

Plug

15

Primary
slow
air

bleed

6

Primary
main
air
bleed

17

Primary
air

vent

pipe

8
Primary
main
nOlzle

Note
Do

not
remove
the

parts
marked
with
an
asterisk

PRIMARY
SYSTEM

Prlmar
main
s
stem

The

primary
main

system
is
a

Stromburg

type
Fuel
flows
as
shown

in

Figure
EF
25

through
the
main

jet

mixting
with
air

which
comes
in

from

the
main

air
bleed
and

passes
through

the

emulsion
tube
and
is

pulled
out

into

the
venturi

through
the
main

nozzle

IdUns
and
slow
s
stem

During
low

engine
speed
as

shown

in

Figure
EF
25

fuel
flows

through

the
slow

jet
located
on
rear

right
side

of
main

nozzle

mixing
with
air

com

ing
from
the
1st
slow
air
bleed

again

mixing
with
air

coming
from
the
2nd

slow
air
bleed
and
then
is

pulled
out
I

III

@

19

Choke
valve

20

Primary
small
venturi

21

High
speed
enricher

air

bleed

22
Richer
nozzle

23
Richer

jet

24

Secondary
air

vent

pipe

into
the

engine
through
the
idle
hole

and

bypass
hole

Adoption
of
the

submerged

type
of

slow

jet
eliminates

such
hesitation
as

occurs
on
sudden
deceleration
of
the

vehicle

Slow
economizer

system
obtains

smooth
deceleration
at

high

speeds

Small

opening
of
the
throttle

valve

at

idling
or

partial
load

creates
a

large

vacuum

pressure
in
the
intake
mani

fld

By
this

vacuum

pressure
fuel
is

measured

through
the
slow

jet
located

behind
the
main

jet
And
air

coming

from
the
1st

slow
air

bleed
is
mixed

with

fuel
in
the

emulsion
hole

This
mixture
is

further
mixed
and

atomized
with
air

coming
from
the

2nd
slow
air

bleed
The
atomized

mixture
is

supplied
to
the

engine
from

EF15
25

Secondary
main
nozzle

26
Secondary
small
enturi

27
D
C
D
D
a

sembly

28

Secondary
throttle
valve

EF722

Fig
EF
25
Sectional
view

of
carburetor

the
idle
hole
and

bypass
hole
via
the

sow

sysem

passage

Accele

atlns
mechanism

The
carburetor
is

equipped
with
the

piston
type
accelerating
mechanism

linked
to
the

throttle
valve
When
the

primary
throttle
valve
shown
in

Figure
EF
26
is
closed
the

piston

goes
up
and

fuel
flows
from
the

float

chamber
through
the
inlet

valve
into

the

space
under
the

piston
When
the

throttle
valve
is

opened
the

piston

goes
down

opening
the
outlet
valve

and
fuel
is
forced

out
through
the

injector

Engine
Fuel

1
L

if

1

Pump
injector

2
Piston

3

Spring

4

Weight

5

Damper
spring

6
Piston
return

spring

7

Inlet
valve

8
Outlet
valve

EF023

Fig
EF
26
Acceleration

mechanism

Power

valve
mechanism

SECONDARY
SYSTEM

The

power
valve

mechanism
so

called
vacuum

piston

type
utilizes

the

vacuum
below
the
throttle
valve

When
the

throttle
valve
is

slightly

opened
during
light
load

running

high

vacuum
is

created
in

the
intake
mani

fold
This

vacuum

pulls
the

vacuum

piston
upward

against
the

spring

leaving
the

power
valve
closed
When

the
vacuum
below
the
throttle

valve
is

lowered

during
full
load
or

accelerat

ing

running
the

spring

pushes
the

vacuum

piston
downward

opening
the

power
valve
to
furnish

fuel
Secondary
main

lIYlltem

pulled
out

through
the
main

nozzle

into
the
small
venturi

Due
to
the

double
venturi

of
the

secondary
system
the

higher

velocity

air

current

passing
through
the
main

nozzle

promotes
the
fuel
atomization

The
structure
is

almost
the

same
as

the

primary
side
The

secondary
main

system
is

a

Stromburg
type

Fuel
air
mixture

produced
by
the

functions
of
the
main

jet
main
air

bleed

and
emulsion
tube
in

the
same

manner
as
in

the

primary
system
is

11
1

I

1

1

Primary
vacuum

port

2

Secondary
vacuum

port

3

Diaphragm
chamber

cover

of

Diaphragm

spring

S

Diaphragm

6

Secondary
throttle

valve

7

Primary
theo
nle

valve
lWll
I

1
11

l
v
1

Vacuum

piston

2

Power

valve

ET02
a

EF
512

Fig
EF
27
Sectional

view

of

po
r

valve

Fig
EF
28
Full
throttle
al

high
peed

EF

16