ENGINE ELECTRICAL ± Charging System16-6
This test determines whether the alternator output
current is normal.
(1) Before the test, always be sure to check the
following.
Alternator installation
Battery (Refer to GROUP 54 ± Battery.)
NOTE
The battery should be slightly discharged.
The load needed by a fully-charged battery
is insufficient for an accurate test.
Alternator drive belt tension (Refer to
GROUP 11 ± On-vehicle Service.)
Fusible link
Abnormal noise from the alternator while
the engine is running.
(2) Turn the ignition switch off.
(3) Disconnect the negative battery cable.
(4) Disconnect the alternator output wire from the
alternator ªBº terminal. Connect a DC test
ammeter with a range of 0 ± 100 A in series
between the ªBº terminal and the disconnected
output wire. (Connect the (+) lead of the
ammeter to the ªBº terminal. Connect the (±)
lead of the ammeter to the disconnected output
wire.)
Caution
Never use clips but tighten bolts and nuts
to connect the line. Otherwise loose
connections (e.g. using clips) will lead to
a serious accident because of high current.
NOTE
An inductive-type ammeter which enables
measurements to be taken without
disconnecting the alternator output wire should
be recommended.
(5) Connect a voltmeter with a range of 0 ± 20 V
between the alternator ªBº terminal and the
earth. (Connect the (+) lead of the voltmeter
to the ªBº terminal, and then connect the (±)
lead of the voltmeter to the earth.)
(6) Connect the negative battery cable.
(7) Connect a tachometer. (Refer to GROUP 11
± On-vehicle Service.)
(8) Leave the hood open.
(9) Check that the reading on the voltmeter is equal
to the battery voltage.
NOTE
If the voltage is 0 V, the cause is probably
an open circuit in the wire or fusible link between
the alternator ªBº terminal and the battery (+)
terminal.(10)Turn the light switch on to turn on headlamps
and then start the engine.
(11) Immediately after setting the headlamps to high
beam and turning the heater blower switch to
the high revolution position, increase the engine
speed to 2,500 r/min and read the maximum
current output value displayed on the ammeter.
Limit: 70% of normal current output
NOTE
For the nominal current output, refer to the
Alternator Specifications.
Because the current from the battery will
soon drop after the engine is started, the
above step should be carried out as quickly
as possible in order to obtain the maximum
current output value.
The current output value will depend on
the electrical load and the temperature of
the alternator body.
If the electrical load is small while testing,
the specified level of current may not be
output even though the alternator is normal.
In such cases, increase the electrical load
by leaving the headlamps turned on for
some time to discharge the battery or by
using the lighting system in another vehicle,
and then test again.
The specified level of current also may not
be output if the temperature of the alternator
body or the ambient temperature is too
high. In such cases, cool the alternator and
then test again.
(12)The reading on the ammeter should be above
the limit value. If the reading is below the limit
value and the alternator output wire is normal,
remove the alternator from the engine and
check the alternator.
(13)Run the engine at idle after the test.
(14)Turn the ignition switch off.
(15)Remove the tachometer.
(16)Disconnect the negative battery cable.
(17)Disconnect the ammeter and voltmeter.
(18)Connect the alternator output wire to the
alternator ªBº terminal.
(19)Connect the negative battery cable.
CHASSIS ELECTRICAL ± Radio and Tape Player54-69
A-8 Noise sometimes appears on FM during travelling.
Does the problem clear up when retuned?Ye sOK
No
Does the problem appear only in certain locations and only with
certain stations?Ye sDue to electrical field conditions. (Multipath noise*, fading noise*).
Are connectors properly connected?NoCheck connector connections.
Ye s
Does noise appear when the radio switch is turned on while the
vehicle is stopped and the radio is struck while tuned away from
a station?NoStatic electricity noise:
Body static electric from the shock absorber rubber bushings used
to prevent vibration, tyres, etc. occurs because of separation from
the earth, causing a buzzing noise. Since no measures can be
taken on the radio side, other steps should be taken to discharge
the static electricity of the vehicle body.
Ye s
Is the radio body correctly earthed? (Is the mounting screw tightened
securely?)NoTighten the screw securely.
Ye s
Is the antenna correctly earthed? (If noise appears when the antenna
is moved, this means the earth is not securely connected.)NoIf rust is present at the antenna earth screw, clean and tighten
the earth securely.
Ye s
Repair or replace radio.
No
* About multipath noise and fading noise
Because the frequency of FM waves is
extremely high, it is highly susceptible to effects
from geological formations and buildings.
These effects disrupt the broadcast signal and
obstruct reception in several ways.
Multipath noise
This describes the echo that occurs when
the broadcast signal is reflected by a largeobstruction and enters the receiver with
a slight time delay relative to the direct
signal (repetitious buzzing).
Fading noise
This is a buzzing noise that occurs when
the broadcast beam is disrupted by
obstructing objects and the signal strength
fluctuates intricately within a narrow range.
