1973 DATSUN B110 open gas tank

EMISSION
CONTROL
AND

TUNE
UP

CD

@

Fresh
air

Blow

by

gas

Air
used
in

filtering
oil
1
PCV
valve

2
Flame
arrester

3
Oil
filler

cap

4

Baffle

plate
and

steel
net

E
C002

Fig
ET
J8
Crankcase
emission
control

system
at

full
throttle

open

Checking
and

replacing
PCV
valve

Test
PCV

valve
in
accordance
with
the

following

me
thod

With

engine
running
at
idle
remove
the
ventilator
hose

from
PCV

valve
If
the
valve
is

working
a

hissing
noise

will
be

heard
as
air

passes
through
the
valve
and

a

strong

vacuum
should
be
felt

immediately
when

a

finger
is

placed

over
the
valve
inlet
If
the
valve
is

plugged
replace
with

a

new
one
Check
for

deposit
plugging
in
the
hose
Clean
if

necessary

Intake
manifold

l

illlr
nnnl

UUUU
l
I

G

EC014

FigET
39
Cross
sectional
view

of
PCV
valve
Checking
ventilation
hoses

I
Check
hoses

and
hose
connections
for
leaks

2
Disconnect

all
hoses
and
blow
them

out
with

compressed
air

If

any
hose
can
not
be
free
of

obstructions

replace

with
a

new
one

Insure

that
the
flame
arrester
is

surely
inserted
in

the

hose

between
the
air
cleaner
and
rocker

cover

EVAPORATIVE
EMISSION

CONTROL
SYSTEM

Checking
engine
compartment
hose

connections
and
fuel

vapor
control

valves

Checking
fuel
tank

vapor
liquid
separator
and

vapor

vent
line

I

Check
all
hoses
and
fuel
tank

ftIler

cap

2

Disconnect
the

vapor
vent
line

connecting
flow

guide
valve
to

vapor
liquid

separator

ET
23

FUEL
SYSTEM

If
no

gasoline
or

only
a
little
flows
from

open
end

of

pipe
the
fuel

pipe
is

clogged
or
the

pump
is
malfunction

ing
Before

removing
the

pump
remove
the

gas
tank

cap

disconnect
both
inlet
and
outlet

pipes
and
blow

through

them
with
an
air
hose

to
make
sure
that

they
are
clear

This
will
eliminate

possible
clogged
gas
strainer
in
the

fuel
tank
Reconnect
the

pipes
to
the

pump
and

retest

flow

REMOVAL
AND
DISASSEMBLY

Remove

the
fuel

pump
assembly
by
unscrewing
two

mounting
nuts
and
disassemble
in
the

following
order

1

Separate
the

upper
body
and
the

lower

body
by

unscrewing
the

body
set
screws

2
Take

off
the

cap
and
the

cap
gasket
by
removing
the

cap
screw

3
Unscrew

the
elbow
and
the

connector

4
Take

off
the
valve
retainer

by
unscrewing
two

valve

retainer

screws
Two

valves
are

easily
removed

@

@

GS
5
To
remove
the

diaphragm
diaphragm
spring
lower

body
seal
washer

and
lower

body
seal
from
the

lower

body
press
down

the

diaphragm
counter
to

the
force
of

the

diaphragm

spring
and
while

doing
this
cant
the

diaphragm
so
that
the

rectangular

part
in
the

lower
end
of

the

pull
rod
is

unhooked
from
the
rocker

arm
link

Fig
EF
jJ
StructuTe

of
fuel
pump

EF
7
j

i

I
of

4

Fig
EF
12
Pull
Tad
Temoval

r1
r

f
i

t

1

2

3

4

5

6

7

B

9

10

tt

t2

t3

t4

15

t6

t7

tB

t9

20

2t

22

23

24
Valve
assem

bly

Packing

Retainer

Screw

Cap

Gasket

Screw

Washer

spring

Rocker
arm

Rocker

pin

Rocker
arm

spring

Spacer

Diaphragm
assembly

Retainer

Diaphragm
spring

Washer

spring

Nut

Washer

plain

Gasket

Spacer

Complete
body
lower

Connector
inlet

Connector
outlet

FUEl
SYSTEM

EVAPORATIVE
EMISSION

CONTROL
SYSTEM

CONTENTS

OESCRI
PTION

Flow

guide
valve

MAINTENANCE

AND

TESTING

Checking
fuel
tank

vapor

liquid
separator

and

vapor
vent
I
ins
EF
25

EF

26

EF

26

EF

26

DESCRIPTION

This

system
consists
of

four
basic
elements

indicated

below

I

Fuel
tank

with

positive
sealing
filler

cap
with
relief

valve

2

Vapor

liquid
separator

3

Vapor
vent
line

4
Flow

guide
valve

The
flow

guide
valve

prevents
blow

by

gas
from

flowing
into
the
fuel
tank

and

guides
fresh
air
into
it

preventing
gasoline

vapor
from

escaping
into
the

carbure

tor
air
cleaner

Fl

me
ester

I

f
Flow

Thev
lve

opens
when

thlp
1l

rO

Inch

Hg

O
Positive
unk

venlI1atlon

PCV
hoe
Checking
fuel

tank
vacuum
relief
valve

operation

Checking
flow

guide
valve
EF
27

EF
27

Flow

guide
valve

operates
and
blow

by

gas
and

gasoline

vapor
flow
as
follows

When
the

engine
is
not

running
the

vapor
vent

line

vapor
liquid
separator
and

fuel
tank

are
filled
with

gasoline
vapor
produced
in
the

sealed

type
fuel
tank

A

flow

guide
valve

opens
when
the

gas

pressure
is

above

IOromHg
0
4

in

Hg
The

gas

passed
through
the
flow

guide
valve
2
is

accumulated
in

the
crankcase

Once
the

engine
starts

evaporates
in

the
crankcase

manifold
and

carburetor
air
cleaner

is
sucked
into
the
manifold
for

combustion
When
the

pressure
of
the

sealed

type
fuel

tank

vapor
liquid

separator
and

vapor
vent
line

becomes

negative
by

decreasing
the
fuel
the

flow

guide
valve
I

opens
to
send
fresh
air
from
the
carburetor
air
cleaner

to

the

fuel
tank

lill
K
riquidllepilrflOr

T

VilPOl
vent

line
Positiveteilling

lillercap

Fig
EF
37

Evaporative
emission

control

system

EF
25