1973 DATSUN B110 fuel consumption

ENGINE

Caution

lock
the
front

and
rear
wheels

by
fully

pulling
the

parking
brake
lever
before
con

ducting
this
test

Fig
ET
32

Checking
for
operation
of
vacuum

advance

system

If

any
objection
is

found

by
the
check

mentioned

above

either
of
the

following
defects

may
be
the

cause

Poor
connection
or

broken
harness
and
fuse

2
Air

leakage
resulting
from

poor
connection
of
vacu

um
tube

3
Incorrect

operation
of

Top
switch

4
Defective

operation
of
vacuum

cutting
valve
sole

naid

5
Incorrect

operation
of
thermo
switch

Testing
of

Top
switch

1
Make
sure
of
insulation
between
lead
wire

terminal

of
transmission
switch
and
switch

body

2

Disconnect
lead
wires
at
the
switch

and
connect

ohmmeter
to
tenninals

3
Ohmmeter

should
indicate

infmity
co
when
shift

lever

is
in

Top
gear
position
And
it
should
indicate

zero
at
other

gear
position
including
Neutral

posi

tion

4
If

it
does
not

work

properly
in

step
3

replace
the

switch
with
a
new
one

Testing
of
thermo
switch

I

MaJ
e

sure
of

insulation
between
lead
wire
terminal

of
thermo
switch
and
thetmo
switch

body

2

Disconnect
lead
wire

at
switch
and
connect
ohm

meter
to
terminals
Ohmmeter
should
indicate
zero
when

temperature

indicate
the

passenger
compartment
is
above
l30C

550F

4
If
it
does

not
work

properly
in

step
3

replace

thermo
switch
with
a
new

one

AUTOMATIC

TEMPERATURE

CONTROL
AIR
CLEANER

A
T
C
AIR

CLEANER

Replacing
carburetor
air
cleaner

filter

The

paper
element

viscous

type
has
been

specially

treated
to

eliminate
bother

of

cleaning
until

replacement

It

should
be

replaced
with
a

new
one
at

regular
intervals

or
more
often

according
to
the

operating
conditions

Checking
hot
air
control
valve

Inspection

Among
the

possible
troubles
of
this
device
the

most

liable
is
the

permanent
opening
of
valve

This
trouble
is
not

noticed
in
warm
weather
but
in

cold
weather

appears
as

poor

performance
of

engine

such

as

tardy
acceleration
hesitation
or

engine
stall
In

such

case
first

inspect
this

device
before

checking
the

carburetor

Another
trouble
which

might
be

expected
is
that
the

underhood
air
is

kept
closed

by
the
valve

regardless
of

the

temperature
of
suction
air
around
the

sensor
while

the

engine
is

running
This
ttOuble

appears
in
the

form

of

extremely
excessive
fuel

consumption
or
decrease
in

power

The

inspection
of
this
device

should
be

proceeded
as

follows

Fig
ET

33
Correct

position
of
hoses

ET
20

ABNORMAL

COMBUSTION

backfire
afterflfe

run
on
etc

Improper
ignition
timing

Fuel

system
in
trouble

Defective

cylinder
head

etc

EXCESSIVE
OIL

CONSUMPTION

Oil

leakage

Excessive
oil

consumption
ENGINE

Improper
ignition
timing

Improper
heat

range
of

the

spark
plugs

Damaged
carburetor
or
manifold

gasket

backfire
afterflre

Defective
carburetor

jet

Improper
function
of
the
float

Uneven

idling

Improperly
adjusted
valve
clearance

Excess
carbon
in
the
combustion
chamber

Damaged
valve

spring
backfire
afterure

Loose
oil
drain

plug

Loose

or

damaged
oil

pan
gasket

Loose
or

damaged
chain
cover

gasket

Defective
oil
seals
in
front
and

rear
of
the

crankshaft

Loose
or

damaged
locker

cover
gasket

Improper
tightening
of
oil
filter

Loose
or

damaged
oil

pressure
switch

Worn

cylinder
and

piston

Improper
location
of
the

ring
split
or
reo

versed

assembly

ET
32
Adjust
the

ignition
timing

Use

specified
spark
plugs

Replace
them
with
new
ones

Disassemble
the
carburetor
and

check

it

Adjust
the
level
and

check
the
needle

valve

Adjust

Readjust

Remove
the

cylinder
head
and

remove

carbon

Replace
it
with

a
new
one

Tighten
it

Renew
the

gasket
or

tighten
it

Renew
the

gasket
or

tighten
it

Renew
the
oil

seals

Renew
the

gasket
or

tighten
it

Do
not

tighten
excessively

Renew
the

gasket
and

tighten
it
cor

rectly

Retighten
or
renew

the
oil

pressure

switch

Overhaul
the

cylinder
and
renew
the

piston

Reassemble
the

piston
rings
correctly

EMISSION
CONTROL
AND

TUNE
UP

Othm

POOR
FUEL

CONSUMPTION

See
the

explanation
of

the

power
decrease

Othe

TROUBLE
IN

OTHER

FUNCfIONS

Decreased
oil

pressure

Excessive
wear

on
the

sliding

parts
Damaged
or
seized

piston
rings

Worn

piston
ring
groove
and

rings

Fatigue
ofvalve
oil
seal

lip

Worn
valve
stem

Inadequate
quality
of

engine
oiL

Engine
overheat

Exceeding
idling
revolution

Defective
acceleration

recovery

Fuel

leakage

Inadequa
Ie
oil

quality

Overheat

Defective
function
of
oil

pump
regulator

valve

Functional
deterioration
of
oil

pump

Blocked
oil
ftIter

nerased
clearance
in
various

sliding
parts

Blocked
oil
strainer

Troubles
in
the
oil

gauge
pressure
switch

Oil

pressure
decrease

Defective

quality
or
contamination
of
oil

Defective
air

cleaner

Overheat
or
overcoal

ET
33
Renew
the

rings

Repair
or
renew
the

piston
and

cyl

inder

Renew
the

piston
and

piston
ring

Replace
the

seal

lip
with
a
new
one

Renew

the
valve
or
the

guide

Use
the

designated
oiL

Previously
mentioned

Adjust
it
to
the

designated
rpm

Adjust
it

Repair
or

tighten
the
connection

of

fuel

pipes

Use

the

designated
oil

Previously
mentioned

Disassemble
the

oil

pump
and

repair
or

renew
it

Repair
or

replace
it
with

a
new
one

Renew

it

Disassemble
and

replace
the
worn

parts
with

new
ones

Clean
it

Replace
it

with
a

new
one

Previously
mentioned

Replace
the
oil
with

proper
one
and

change
the

ftIter
elemerit

Replace
the
air

cleaner
element

Previously
mentioned

ENGINE

Choke

unloader
clearance

carburetor

body
C

between
choke
valve
and

mm
in

Bi
metal
resistance

ohms
2
01

0
07911

8

6t09
0

Accelerator

pump

Injector
hole

Return

spring

Fuel

pressure
mm
in

g
mm

Ib
in

kg
cm
2

psi

kg
lb
0
5

0
0197

78
I
I

0
18
2
6

Manual
transmission

Automatic
transmission
Weight
2
8
6
2

2
9
6
39

Example
1
215

represents
215
100
2
15

mm
0
0846
in

diameter

TROUBLE
DIAGNOSES

AND
CORRECTIONS
There
are
various
causes
of

engine
tarubles
It

some

times

happens
that
the

completely
effective

carburetor

seems

apparently
to
have

some
troubles

when
electric

system
is

defective
Therefore
whenever
the

enigne
has

troubles
electric

system
must
be

checked
first
before

adjusting
the

carburetor
In
the

following
table
the

symptoms
and

causes
of

carburetor
tarubles
and
remedies

for
them

are
listed

to

facilitate

quick

repairs

Troubles

Possible
causes
Remedies

Overflow
Dirt

accumulated
on

needle
valve
Clean
needle
valve

Fuel

pump
pressure
too

high
Repair

pump

Needle
valve
seat

improper
Lap
or

replace

Excessive

fuel

consumption
Fuel
overflows
See
above

Each
main
air

bleed

clogged
Clean

Gauge
plate

adjustment
incorrect

Correct

adjustment

Choke
valve
does

not

open

Adjust

Outlet
valve
seat

of
accelerator

pump
im

proper
Lap
or

replace

Linked

opening
of

secondary
throttle
valve

too

early
Adjust

Power

shortage
Each
main

jet
clogged
Clean

Each
throttle
valve

does
not

fully
open
Adjust

Fuel

pump
operated
improperly
Repair

EF
22