54-164
CHASSIS ELECTRICAL
-
Radio and Tape Player
A-6
There is noise when starting the engine.
Noise
type
Sounds
are
in
pa-
rentheses
(
).
AM,
FM:
Ignition
noise
(Popping,
Snap-
ping,
Cracking,
Buzzing)
Other
electrical
components
Static
electricity
(Cracking,
Crin-
kling)
Conditions
0
Increasing
the
engine
speed
causing
the
popping
sound
to
speed
up,
and
volume
de-
creases.
0
Disappears
when
the
ignition
switch
is
turned
to
ACC.
-
l
Disappears
when
the
vehicle
is
completely
stopped.
Occurs
when
parts
or
wir-
Severe
when
the
clutch
is
en-
ing
move
for
some
reason
l
gaged.
and
contact
metal
parts
of
the
body.
l
Various
noises
are
produced
de-
pending
on
the
body
part
of
the
vehicle.
Due
to
detachment
from
the
body
of
the
front
hood,
bumpers,
exhaust
pipe
and
muffler,
suspension,
etc.
Cause
l
Mainly
due
to
the
spark
plugs.
l
Due
to
the
engine
noise.
Noise
may
appear
as
electrical
components
be-
come
older.
Parts
to
be
Location
of
inspected
parts
or
remedy
(next
page)
Noise
con-
1
denser
Ground
cable
2,
3
Repair
or
replace
electrical
components.
Return
parts
or
wiring
to
their
proper
position.
Caution
1.
Connecting a high tension cable to the noise
filter may destroy the noise filter and should
never be done.
2.
Check that there is no external noise. Since
failure to do this may result in misdiagnosis
due to inability to identify the noise source,
this operation must be performed.
3. Noise prevention should be performed by
suppressing strong sources of noise step
by step.
NOTE
1.
Condenser
The condenser does not pass D.C. current, but
as the number of waves increases when it
passes A.C. current, impedance (resistance
against A.C.) decreases, and current flow is
facilitated. A noise suppressing condenser
which takes advantage of this property is in-
serted between the power line for the noise
source and the ground. This suppresses noise
by grounding the noise component (A.C. or
pulse signal) to the body of the vehicle.
2. Coil
The coil passes D.C. current, but impedance
rises as the number of waves increases relative
to the A.C. current. A noise suppressing coil
which takes advantage of this property is in-
serted into the power line for the noise source,
and works by preventing the noise component
from flowing or radiating out of the line.
1
TSB Revision
Ground
parts
by
bonding.
Cases
where
the
problem
is
not
eliminated
by
a
single
response
to
one
area
are
common,
due
to
several
body
parts
being
imperfectly
grounded.
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