Associated Equipment 6042 - Manual (Page 5)

5
STARTER TESTS
„ Current draw of the starter, battery voltage, and
voltage drop of leads can be measured when
connected as shown (See figure 8).
„ Before running any starter tests, disable the engine
by removing the coil wire from the distributor or by
disconnecting the battery leads to the distributor
(HEI). Be sure that any leads that are removed are
insulated to prevent shorting to ground.
„ Review the Safety section in the front of this manual.
1)
Attach the heavy duty leads to the battery as
shown. Attach the AMPS PROBE around the
lead from the positive battery terminal to the
starter. If that cable is not accessible, it may be
placed around the ground cable that runs from
the frame or engine block to the negative battery terminal.
Make sure VOLTS switch is in INT position.
2) Be sure that all the lights and accessories are turned off.
3) Crank the engine while watching both the VOLTS meter
and the AMPS meter. After 2-3 seconds of cranking, the
readings should be fairly stable. If not, continue cranking
until they are stable. Under no condition should you crank
more than 10 seconds at a time.
4) Minimum acceptable voltage for most vehicles while
cranking is 9.6 volts. Typical starting currents for vehicles
are:
4 cylinder gas engine--up to 175 amps
6 cylinder gas engine--up to 225 amps
8 cylinder gas engine--up to 250 amps
8 cylinder gas engine--up to 650 amps
„ The vehicle service manual should be consulted for more
detailed information. While the vehicle is cranking, you should
listen for high pitch or low growling sounds that may indicate
bearing or other problems.
„ Connections between the battery and starter and between the
battery and frame should also be checked at this time.
Excessive voltage drop in either cable caused by loose or
corroded connections, undersized, or broken wires may be the
problem, not the starter.
PROPER TEST PROCEDURE IS AS FOLLOWS:
1)
Attach tester to battery as shown. Switch VOLTS to EXT
position.
2) Attach positive light gauge lead to positive battery terminal.
Attach negative light gauge lead to starter solenoid where the
lead from the battery terminates.
3) Crank engine and read voltage drop of cable when readings
stabilize.
4) Repeat the same procedure, checking the voltage drop across
the solenoid, (negative lead to starter side of solenoid).
5) Repeat again, checking the voltage drop between the solenoid
and the starter. (Positive lead at solenoid, negative lead at
starter.)
6) Repeat again, checking the ground cable from the battery to
the engine block. (Positive lead to engine block, negative lead
to battery negative terminal.)
7) Acceptable voltage drop on any wire lead should be 0.2 volts or
less. Voltage drop across the starter solenoid should 0.3 volts
or less. Check vehicle service manual for further details.
CHARGING SYSTEM TESTS
„ Please review all the safety instructions in the front of
this manual before running these tests.
„ Charging problems can be caused by a number of
different things. These can include loose belts,
defective diodes or stators, defective regulators,
corroded or loose connections or defective diode trios
(GM cars).
„ Undercharging will shorten battery life and may not
provide the proper charge to start the vehicle.
Overcharging will cause excess water usage in the
battery and shorten battery life.
„ Proper charging voltage and current from the charging
system to the battery is important for the longest life
and maximum performance.
„ The proper end of charge voltage will depend on the type of
battery installed by the manufacturer and ambient temperature
of the charging system.
●
A conventional battery (lead-antimony ) will require
charging voltages up to about 14.5 volts.
● A recombination battery or low maintenance battery will
require charging voltages up to about 15.0 volts.
● A maintenance free battery will require charging voltages
up to about 15.5 volts.
„ Voltage specifications will vary from manufacturer to
manufacturer. The service manual for the vehicle should be
consulted for exact charging specifications.
It is also important that the charging system be capable of putting
out it's rated current. If the electrical load, (lights, blower, power
accessories, etc.) in the vehicle is more than the output of the
alternator, the battery will discharge to provide the needed current.
The battery may become discharged and will not recharge until
some of the load is turned off. This type of discharge/charge cycle
will greatly shorten the life of the battery. Therefore, output current
as well as output voltage of the charging system should be checked.
NOTE: A check of the charging system should include a check of
the battery cables to ground and to the alternator to determine bad
connections.
FIGURE 8
STARTER
MOTOR
STARTER
SOLENOID
FRAME
FRAME
+ -
BLACK
LEAD RED
LEAD
TO
ACCESSORIES
FRAME
+ - BLACK
LEAD RED
LEAD
FIGURE 9
ALTERNATOR
FRAME