1977 DATSUN PICK-UP spark plugs

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

FUSIBLE
LtNK

m
Engine
Electrical

System

E

CJI2t

Bf
o

00

00

fOl

R

BL
I

ti
L

oj

L
C
J

RESISTOR

IGNITION
COIL

COLOR
CODE

B
Black

OW

Black
with
white

stripe

DR
Black
with

red

stripe

aL
Black
with
blue

stripe

W
White
W

R

Wj
BW

BR

IGNITION
SWtTCH

DISTRtBUTOR

jjj

SPARK
PLUGS

EE493

EE
27
Fig
EE
54
Circuit

diagram
of
ignition
ByJt
m
Non

California
models

Primary
winding

1

Ignition
coo

I

Secondary

winding
CALIFORNIA
MODELS

The

ignition
circuit

consists
of

igni

tion

switch
transistor

ignition
unit

distributor

wiring
spark

plugs
and

battery

The

distributor
is
of
the
contactless

type
and
is

equipped
with
a

pick
up

coil
which

electrically
detects
the

igni

tion

timing

signal
in

place
of
the

circuit

breaker
of
the
conventional

distributor
The
transistor

ignition
unit

is
a
new
addition
which

generates
the

signal
required
for
the
make

and
break

of
the

primary
electric
current
for
the

ignition
coil

The
circuit
is

equipped
with
a

resistor

During
cranking
electrical

current

bypasses
the

secondary
resis

tor

thereby
connecting
the

ignition

coil

through
the

primary
resistor
This

makes

battery
voltage
available
at
ef

ficiently
and

keeps
ignition
voltage
as

high
as

possible

The

primary
resistor

selVeS
to

pro

tect
transistor

ignition
circuit

The
low

voltage
current
is

supplied

by
the

battery
or
alternator
and
flows

through
the

primary
circuit

It
consists
of
the

ignition
switch
Engine
Electrical

System

resistor

primary
winding
of
the

igni

tion

coil
transistor

ignition
unit
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

secondary

winding
of

the

ignition
coil
distribu

tor

high
tension
wires
to
coil
and

spark
plugs
distributor
rotor
and

cap

When
the

ignition
switch
is
turned

on
and
the

distributor
reluctor
rotates

the

primary
current
flows

through
the

primary
winding
of
the

coil
and

through
transistor

ignition
unit
to

ground

When
the

prim

ary
circuit
is

opened

by
circuit

of
transistor

ignition
unit

the

magnetic
field

built

up
in
the

primary
winding
of
the
coil
moves

through
the

secondary

winding
of
the

coil

inducing
high
voltage
This

high

Battery
Primary
Secondary

I

Resistor

To

starter

r
Transis
tor

ignition

unit
I

I

Pick
up

rcoil

r
Rotor
head

nl

J
R5

U1f

1

Retuctor
r
oi

l
f
S

park

plugs
voltage
is

produced

every
time
the

primary
circuit

opens

The

high

voltage
current
flows

through
the

high
tension
wire
to

the

distributor

cap
then
the
rotor

distri

butor

cap
then
the

rotor
distributes

the

current
to

one
of

the

spark
plug

terminals
in

the
distributor

cap

Then
the

spark
occurs
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

spark

plug
should
be

inspected

cleaned
and

regapped
at
tune

up

Spark
plugs
should
also
be

replaced

periodically
as

specified
in
the
Main

tenance
Schedule

The

remainder
of
the

ignition
com

ponent
parts
should

be

inspected
for

only
their

operation
air

gap
of

distri

butor

tightness
of
electrical
terminals

and

wiring
condition

Apply
grease

NLGI
consistency

No
I

containing
MoS
or

equivalent

to
distributor
rotor
shaft
as

required

EE287

EE
28
Fig
EE
55

Ignition

8Y3tem
circuit

diagram

EARTH
POINT

r

W

b

FUSIBLE

LINK

BATTERY

L
d

l

ilR
j

i

BW
@
c

RESISTOR

COLOR
CODE

8

Black

OW
Black

with
white

stripe

DR

Black
with
red

stripe

W
White

L
Blue

R

Red

G
Green
Engine
Electrical

System

TRANSISTOR
IGNITION

UNIT

IHIIl
II
II

BW

BBV
RG

111
I

I

TERMINAL
BLOCK

r
c

IGNITION
COIL
BW

B

ml
BR

lliJ

LldJ0

IGNITION
SWITCH

EE

29
Fig
EE
56
Circuit

diagram
of
ignition
system
California
models
EE494
a
B

lof1
@

00

00

00

SR

00

00

Et
liiI

in

D1STRliUTOR

10
0

i9

J

SPARK
PLUGS

Engine
Electrical

System

Transistor

ignition
unit

r
1
Power

switching

circuit
Duty

control

circuit

To
starter

To
distributor

Ba

ttery
Ignition
coil
1
Spark
timing

1
Signal
mom

toring
circuit
Lock

j
preven
ling

circuit

nm

Distributor

EE437

Fig
EE
75
Transistor

ignition
unit
circuit

diagram

REMOVAL
AND

INSTALLATION

Transistor

ignition
unit
is

located

on
the

right
hand
dash

side

panel
in

passenger
compartment

Disconnect

battery
negative
cable

2
Disconnect

wiring
harness
from

unit

3
Remove
two

setscrews
and
te

move
unit

4

To
install
reverse
the
order
of

removal

Note
Be

sure
to
connect

wiring
har

nesses
to
their

proper

positio

Failure
to
do
so
will

damage
the

unit

Refer
to

Figure
EE
76

Fig
EE
76
External
view

of

ignition

unit
INSPECTION

If
the

engine
does

not
run
due

to

faulty
ignition
system
check
the

igni

tion

system
as
follows

Check
for
a
cracked
distributor

rotor
or

cap
and
corroded
tenninals

Visually

inspect
high
tension
wires

for

condition
and
if

necessary
use
an

ignition
oscilloscope
or
a
circuit
tester

to
make

performance
checks
Check

spark
plugs
and

adjust
gaps
as
neces

sary

Replace
a

spark
plug
which

is
not

suitable
for
further
use
If
the

above

checks
cannot
correct
the

problem

check
the
entire

ignition
system
with

an

oscilloscope
or

a
circuit

tester

L
CHECKING
WITH
AN

OSCILLOSCOPE

An

oscilloscope
can
be
used
for

checking
almost

all
the
items
in

a

transistor

ignition
system

CHECKING
WITH
A

CIRCUIT

TESTER

A
circuit
tester
can
not
be

used
for

the

duty
control
circuit

and

power

t18nsistor

performance
tests

Both

methods
use
of

an

oscilloscope
and
a

circuit
tester

are
described
in
this

section

EE

37
The
items

are
classified

by
numerals

in

accordance
with
the

objective
of

checks
to

be

performed
Several

wiring

diagrams
are
found

on

pages
EE
41

to

EE
45
The
thick
lines
indicate

the

objective
of

each
individual
item

check

When

checking
a
circuit
with
an

oscilloscope
or
a
circuit
tester
be

careful
not
to

confuse
the

polarity
of

the
lead
wires
if

potential
difference

exists
between
the
check

points
at

which
the
lead
wires
are
to
be
con

tacted

Also
do
not

attempt
to
con

nect
the

lead
wires
to

any
points
in
the

circuit
other

than
those

designated

Careless

handling
of
the
lead
wires

will

result
in

damage
to
the
transistor

ignition
unit

as
well
as
to
the
oscillo

scope
or
circuit

tester

The
connection
of

a
tachometer

or

a

timing
light
in

parallel
with
an

oscilloscope
or
a
circuit
tester
is
al

lowable

provided
that
such
a

connec

tion
is

made
with
due
consideration
to

wiring
connections

1
POWER
SUPPLY

WIRING

AND

BAnERY
CHECK

See

wIrIng
diagram

In

FIgure
EE
88

Procedure

I
Turn
on

ignition
switch

2

Connect

a
circuit
tester
or

an

oscilloscope
as
shown
in
the

figure

below

DC
50
volt

range

EE302

Fig
EE
77

Checking
power
supply

wiring
and

batt

ry

Criterion

When

power
source

battery

voltage
is

indicated
OK

Lower

or
no
indication
N
G

The

ignition
coil
is

an
oil
f1l1ed

type
The

ignition
coil
case

is
filled

with
oil
which
has

good

insulating
and

heat

radiating
characteristics

The

ignition
coil
has
a

greater
ratio

between
the

primary
and

secondary

windings
to

step
up
battery
voltage
t

high
voltage
This
causes

stronger

sparks
to

jump
the

spark
plug

gap

The

cap
is
made
of

alkyd
resin

which
offers

high
resistance
to
lectric

arc
and
increased
insulation

The

ignition
coil
and
resistor
should

be
handled

as
a
matched
set

When

high
tension
wire
is

installed

to

ignition
coil
there
should
be

no

clearance
between
their

caps

I
EE354

1

High
tension
wire

2
Rubber

cap

Fig
EE

94
Correcl
installation

of

high

t
Mjon

win

SPECIFICATIONS

Type

Primary
voltage

Spark
gap

Primary
resistance
at
200C
680F

Secondary
resistance

at
200C
680
F
KSl

External

resistor
at20
C

680F
n
Engine
Electrical

System

IGNITION
COIL

California
models

f
ID

@

J

C

ID

I
1W

1
R

bber

cap
for

ignition
coil

2

Secondary
terminal

3

Cap

4

Primary
terminal

5

Spring

6

Secondary
winding

7

Primary
winding

Notes

a
Do

not
disconnect

high
tension

wires
from

spark
plugs
during
en

gine

mnning
California

models

only

b

RoD

up
high
tension

wire
mbber

cap
and
instaD

high
tension
wire
to

ignition
coil

securely
Refer
to

Figure
EE
9S
Non
califomia

models

EE314

8
Side
core

9
Insulator
coil

10
Center
core

11

Segment

12
Case

13
Rubber

cap
Cor
terminal

Fig
EE
93
Sectional
view

of

ignition
coil

Fig
EE

95

Installing
high
tension
wire

Non

California

California
models

models

C6R
618

HS
15
18
CIT

16
STC
9

12
12

more
than
7

0
28
more
than
7

0
28

1
08
to
1
32
0
45
to

0
55

8
24
to

12
4
8
5
to

12
7

1
5
1
3

0
4
0

9
V

mm
in

n

EE
46

DESCRIPTION

INSPECTION

CLEANING
AND
REGAP

DESCRIPTION

The

spark
plugs
are
of
the

conven

tional

type
having
14
mm
0

551
in

threads
The

spark
plug
gaps
are
1
0
to

1
1
mm
0
039
to
0
043
in
on
Cali

fomia
models
and
0
8

to
0
9
mm

0
031
to

0
035
in
on
non
California

models
The

inspection
and

cleaning

should
be
made
every
suitable
mainte

nance

period
If
necessary
replace

Note
All

spark

plugs
installed
on
an

engine
must
be

of
the
same
brand

and
the

same
number
of
heat

range

INSPECTION

L
Remove

spark
plug
wire

by

pulling
on

boot
not
on
wire
itself

2
Remove

spark
plugs

3

Check
electrodes
and
inner

and

outer

porcelains
of

plugs
noting
the

type
of

deposits
and
the

degree
of

electrode
erosion

Refer
to

Figure

EE
96

Normal
Brown
to

grayish
tan
de

posits
and

slight
electrode
wear

indicate
correct

spark
plug
heat

range

Carbon
fouled

Dry
fluffy
carbon

deposits
on
the
insulator
and

electrode
are

usually
caused

by

slow
speed
driving
in

city
weak

ignition
too
rich
fuel
mixture

dirty
air
cleaner
etc

It
is

advisable
to

replace
with

plugs

having
hotter
heat

range

Oil
fouled
Wet
black

deposits
indi

cate
excessive
oil
entrance
into

combustion
chamber

through
worn

rings
and

pistons
or
excessive
clear

ance
between
valve

guides
and

stems
If
the
same
condition
re

mains
after

repair
use
a
hotter

plug
Engine
Electrical

System

SPARK
PLUG

CONTENTS

EE
4B

EE
47

EE
47

EE
47
SERVICE
DATA
AND
SPECIFICATIONS

TROUBLE
DIAGNOSES
AND

CORRECTIONS
EE
4B

Overheating
White
or

light

gray
in

sulator
with
black
or

gray
brown

spots
and
bluish
burnt
electrodes

indicate

engine
overheating
More

over
the

appearance
results
from

incorrect

ignition
timing
loose

Normal

Overheating

EE079

4
After
cleaning
dress
electrodes

with
a
smaU
fine
file
to
flatten
the

surfaces
of
both
center
and
side

electwdes
in

parallel
Set

spark
plug

gap
to

specification

5
InstaU

spark
plugs
and

torque

each

plug
to
L5

to
2
0

kg
m

11
to
14

ft
Ib

6
Connect

spark

plug
wires

CLEANING

AND
REGAP

Clean

spark
plugs
in

a
sand
blast

type
cleaner
Avoid
excessive

blasting

Clean
and
remove
carbon
or
oxide

deposits
but
do
not

wear
away

porcelain
If

deposits
are
too
stubborn

EE
47
spark
plugs
low
fuel

pump
pres

sure

wrong
selection
of
fuel
a

hotter

plug
etc

It
is
advisable
to

replace
with

plugs

having
colder
heat

range

Ir

i

Carbon
fould

Worn

Fig
EE
96

Spark
plug

discard

plugs

After

cleaning
spark
plugs
renew

firing
surface
of
electrodes
with
me

mentioned
aboVe
Then

gap
spark

plugs
to

specified
values
with
a
round

wire
feeler

gauge
All

spark
plugs
new

or
used
should
have
the

gap
checked

and
reset

by
bending
ground
electrode

EEOBO

Fig
EE
97

Setting
park
plug
gap

Condition

Spark
length

I

to
2
rnm
0
039

to
0
079
in
Of

irregular

More

than
6
rnm

0
236
in
Engine
Electrical

System

Location
Probable
cause

Distributor
Point

gap
too
wide
Non
California
mo

dels

Oil

on
point
Non
California
models

Burned

points
Non

California
models

Spark

plugs
Spark

plug
gap
too
wide

Too
much
carbon

Broken
neck
of
insulator

Expiration
of

plug
life

Air

gap
too
wide
California
models

Distributor

Transistor

ignition

unit
California

models
Faulty
transistor
ignition
unit
Corrective
action

Correct

Clean

Replace

Correct
or

replace

Clean
or
replace

Replace

Replace

Correct

Replace

2

Engine
rotates
but
does
not
run

smoothly

This

may
be

caused

by
the

ignition
system
or
other

engine
condi
Hons
not

related
to

ignition
Therefore
first
a
complete
inspection
of

ignition
system

should
be

carried
out

Condition

Engine
misses
Location
Probable

cause

Distributor
Dirty
point
Non
California
models

Foreign
mattef
on

pick
up
coil
California

models

Improper
point

gap
Non
California
mo

dels

Impropef
air

gap
California
models

Leak
of

electricity
at

cap
and
rotor
head

Damaged
insulation
of
condenser

Non

California
models

Malfunctioning
contact
arm
Non
Cali

fornia
models

Faulty
contact
arm

spring
Non
Cali

fornia
models

Breakage
of
lead
wire
Non
California

models

Breakage
of

pick
up
coil
lead
wire
Cali

fornia
models

Worn

or
shaky
breaker

plate

Worn
or
shaky
distributor

driving
shaft

Layer
short
circuit
or
inferior

quality

coil
Ignition
coil

High
tension
wire
Deterioration
of
insulation
with
con

sequent
leak
of

electricity

EE
49
Corrective
ac
ion

Clean

Clean

Correct

Correct

Repair
or

replace

Replace

Oil
shaft

Replace

Replace

Replace

Replace
assembly

Replace
assembly

Replace
with

good
one

Replace