Download Voltage Drop Testing

OBJECTIVES
After studying Chapter 19, the reader should be able to:
1. Prepare for ASE Electrical/Electronic Systems (A6)
certification test content area “C” (Starting System
Diagnosis and Repair).
2. Explain how to disassemble and reassemble a
starter motor and solenoid.
3. Discuss how to perform a voltage drop test on the
cranking circuit.
4. Describe how to perform cranking system repair
procedures.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTING SYSTEM TROUBLESHOOTING
• The proper operation of the starting system
depends on a good battery, good cables and
connections, and a good starter motor.
• Because a starting problem can be caused by a
defective component anywhere in the starting
circuit, it is important to check for the proper
operation of each part of the circuit to diagnose and
repair the problem quickly.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
VOLTAGE DROP TESTING
• Voltage drop is the drop in
voltage that occurs when
current is flowing through a
resistance.
• Voltage drop testing of the
wire involves connecting a
voltmeter set to read DC
volts to the suspected highresistance cable ends and
cranking the engine.
Automotive Electricity and Electronics, 2/e
By James D Halderman
FIGURE 19-1 To test the voltage drop of
the battery cable connection, place one
voltmeter lead on the battery terminal and
the other voltmeter lead on the cable end
and crank the engine. The voltmeter will
read the difference in voltage between the
two leads which should not exceed 0.2 volt
(200 mV).
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
VOLTAGE DROP TESTING
FIGURE 19-2 Voltmeter hookups for voltage drop testing of a GM-type
cranking circuit.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
VOLTAGE DROP TESTING
FIGURE 19-3 Voltmeter hookups for voltage drop testing of Ford-type cranking circuit.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
VOLTAGE DROP TESTING
• If the difference in the two readings exceeds 0.5
volt, perform the following steps to determine the
exact location of the voltage drop.
– Connect the positive voltmeter test lead to the most-positive end of
the cable being tested. The most-positive end of a cable is the end
closest to the positive terminal of the battery.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
VOLTAGE DROP TESTING
– Connect the negative voltmeter test lead to the other end
of the cable being tested. With no current flowing through
the cable, the voltmeter should read zero because both
ends of the cable have the same voltage.
– Crank the engine. The voltmeter should read less than
0.2 volt.
– Evaluate the results. If the voltmeter reads zero, the cable
being tested has no resistance and is good. If the
voltmeter reads higher than 0.2 volt, the cable has
excessive resistance and should be replaced. However,
before replacing the cable, make certain that the
connections at both ends of the cable being tested are
clean and tight.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
CONTROL CIRCUIT TESTING
• When the ignition switch is rotated to the start position,
current flows through the ignition switch and neutral safety
switch and activates the solenoid.
FIGURE 19-4 A typical Ford solenoid on the left and a typical GM solenoid on the right.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
CONTROL CIRCUIT TESTING
• High current then flows
directly from the battery
through the solenoid and to
the starter motor.
• Therefore, an open or
break anywhere in the
control circuit will prevent
the operation of the starter
motor.
Automotive Electricity and Electronics, 2/e
By James D Halderman
FIGURE 19-5 GM solenoid ohmmeter
check. The reading between 1 and 3 (S
terminal and ground) should be 0.4 to 0.6
ohm (hold-in winding). The reading
between 1 and 2 (S terminal and M
terminal) should be 0.2 to 0.4 ohm
(pull-in winding).
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
CONTROL CIRCUIT TESTING
• If a starter is inoperative, first check for voltage at
the S (start) terminal of the starter solenoid.
• Some newer models with antitheft controls use a
relay to open this control circuit to prevent starter
operation.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
CONTROL CIRCUIT TESTING
FIGURE 19-6 Starter trouble diagnostic chart.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
SPECIFICATIONS FOR A STARTER AMPERAGE TEST
• A starter amperage test
should be performed when
the starter fails to operate
normally (is slow in
cranking) or as part of a
routine electrical system
inspection.
FIGURE 19-7 Starter current can be
measured by using a high current clamp
and a digital multimeter or a specialized
starting and charging tester.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
SPECIFICATIONS FOR A STARTER AMPERAGE TEST
• If exact specifications are not available, the
following can be used as general maximum
amperage draw specifications for testing a starter
on the vehicle.
4-cylinder engines = 150 to 185 amperes
6-cylinder engines = 160 to 200 amperes
8-cylinder engines = 185 to 250 amperes
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
SPECIFICATIONS FOR A STARTER AMPERAGE TEST
• Excessive current draw may indicate one or
more of the following:
1. Binding of starter armature as a result of worn bushings
2. Oil too thick (viscosity too high) for weather conditions
3. Shorted or grounded starter windings or cables
4. Tight or seized engine
5. Shorted starter motor (usually caused by fault with the
field coils or armature)
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER REMOVAL
• After testing has confirmed that a starter motor may
need to be replaced, most vehicle manufacturers
recommend the following general steps and
procedures.
Step 1 Disconnect the negative battery cable.
Step 2 Hoist the vehicle safely.
Step 3 Remove the starter retaining bolts and lower the
starter to gain access to the wire(s) connection(s) on the
starter.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER REMOVAL
Step 4 Disconnect the wire(s) from the starter and remove
the starter.
Step 5 Inspect the flywheel (flexplate) for ring gear damage.
Also check that the mounting holes are clean and the
mounting flange is clean and smooth. Service as needed.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
• To remove the starter motor from the vehicle, first
remove the negative battery cable from the battery
to prevent any possible shorts from causing
personal injury or property damage.
• Before disconnecting the wiring, mark or tag the
location of all wiring connections.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
FIGURE 19-8 Before disassembly of any
starter, mark the location of the through
bolts on the field housing. This makes
reassembly easier.
Automotive Electricity and Electronics, 2/e
By James D Halderman
FIGURE 19-9 Removing the solenoid
from the starter on a GM-type starter
assembly.
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
FIGURE 19-10 Rotate the solenoid to
remove it from the starter housing.
(Caution: The plunger return spring exerts
a force on the solenoid and may cause
personal injury if not carefully released.)
Automotive Electricity and Electronics, 2/e
By James D Halderman
FIGURE 19-11 The brushes should be
replaced if worn to less than 50% of their
original length. Replace if less than 1/2
in.(13 mm) long.
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
FIGURE 19-12 An exploded view of a General Motors starter.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
FIGURE 19-13 To replace the starter drive unit, the retainer and clip must be
removed from the armature shaft. A box-end wrench and a hammer can be used
to pop the retainer off of the spring clip.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
TESTING STARTER ARMATURES
• After the starter drive has been removed from
the armature, it can be checked for run out using
a dial indicator and V-blocks
FIGURE 19-14 Measuring an armature shaft for run-out using a dial
indicator V-blocks.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
GROWLER TEST FOR SHORTED ARMATURE WINDINGS
• If an armature is shorted
(copper-to-copper
connection), it must be
replaced or rewound by a
specialist.
FIGURE 19-15 Using a growler to check for
shorted armature windings.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
TESTING THE ARMATURE FOR GROUNDS
• An open in an armature is usually observed visually
as a loop that is broken or unsoldered where it
connects to the commutator segments.
• A loose or broken solder connection can often be
repaired by resoldering the broken connection using
rosin-core solder.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
ARMATURE SERVICE
• Some manufacturers
recommend that the
insulation between the
segments of the armature
(mica or hard plastic) be
undercut.
FIGURE 19-16 Replacement starter brushes should
be installed so the beveled edge matches the rotation
of commutator.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
TESTING STARTER MOTOR FIELD COILS
• With the armature removed from the starter motor,
the field coils should be tested for opens and
grounds using a powered test light or an ohmmeter.
• The ohmmeter should indicate infinity (no
continuity), and the test light should not light.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER BRUSH INSPECTION
• Starter brushes should be replaced if the brush
length is less than one-half of its original length
(less than 1/2 in. [13 mm]).
• Many starters use brushes that are held in with
screws and are easily replaced, whereas other
starters may require soldering to remove and
replace the brushes.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
BENCH TESTING
• Every starter should be tested before installation in
a vehicle.
• A typical amperage specification for a starter being
tested on a bench (not installed in a vehicle) usually
ranges from 60 to 100 amperes.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER INSTALLATION
• Following are the usual steps needed to be
performed to install a starter.
Step 1 Check service information for the exact wiring
connections to the starter and/or solenoid.
Step 2 Verify that all electrical connections on the starter
motor and/or solenoid are correct for the vehicle and that
they are in good condition.
Step 3 Attach the power and control wires.
Step 4 Install the starter, and torque all the fasteners to
factory specifications.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER DRIVE-TOFLYWHEEL CLEARANCE
• Many starters use shims,
which are thin metal strips
between the flywheel and
the engine block mounting
pad to provide the proper
clearance.
FIGURE 19-17 A shim (or half shim) may be
needed to provide the proper clearance between
the flywheel teeth of the engine and the pinion
teeth of the starter.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER DRIVE-TOFLYWHEEL CLEARANCE
• To be sure that the starter is shimmed
correctly, use the following procedure.
Step 1 Place the starter in position and finger tighten the
mounting bolts.
Step 2 Use a 1/8 in. diameter drill bit (or gauge tool) and
insert between the armature shaft and a tooth of the engine
flywheel.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER DRIVE-TO FLYWHEEL CLEARANCE
Step 3 If the gauge tool cannot be inserted, use a full length
shim across both mounting holes which will move the starter
away from the flywheel.
Step 4 Remove a shim(s) if the gauge tool is loose between
the shaft and the tooth of the engine flywheel.
Step 5 If no shims have been used and the fit of the gauge
tool is too loose, add a half shim to the outside pad only. This
moves the starter closer to the teeth of the engine flywheel.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTING SYSTEM SYMPTOM GUIDE
• The following list will assist technicians in
troubleshooting starting systems.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTING SYSTEM SYMPTOM GUIDE
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
LIGHTS ON TO CRANK
• This simple theft deterrent uses a relay to prevent
the engine from cranking unless the parking lights
are turned on first.
FIGURE 19-18 This
simple theft deterrent
circuit will prevent the
engine from cranking
unless the lights are
turned on first. The lights
do not have to remain on
after the engine starts.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER AMPERAGE DRAW TEST
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER AMPERAGE DRAW TEST
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
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STARTER AMPERAGE DRAW TEST
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
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Voltage Drop Testing
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
Voltage Drop Testing
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
Voltage Drop Testing
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
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STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
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STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
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STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
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STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
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STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
STARTER OVERHAUL
Step-by-Step
Automotive Electricity and Electronics, 2/e
By James D Halderman
cont
© 2009 Pearson Education, Inc.
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SUMMARY
1. Proper operation of the starter motor depends on
the battery being at least 75% charged and the
battery cables being of the correct size (gauge)
and having no more than 0.2 volt drop.
2. Voltage drop testing includes cranking the engine,
measuring the drop in voltage from the battery to
the starter, and measuring the drop in voltage
from the negative terminal of the battery to the
engine block.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
SUMMARY
3. The cranking circuit should be tested for proper
amperage draw.
4. An open in the control circuit can prevent starter
motor operation.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
REVIEW QUESTIONS
1. List the parts of the cranking circuit.
2. Explain how to perform a voltage drop test of the
cranking circuit.
3. List the steps necessary to overhaul a starter.
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
CHAPTER QUIZ
1. A growler is used to test what starter
component?
a)
b)
c)
d)
Field coils
Armatures
Commutator
Solenoid
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
CHAPTER QUIZ
2. Two technicians are discussing what could be the
cause of slow cranking and excessive current
draw. Technician A says that an engine
mechanical fault could be the cause. Technician B
says that the starter motor could be binding or
defective. Which technician is correct?
a)
b)
c)
d)
Technician A only
Technician B only
Both Technicians A and B
Neither Technician A nor B
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
CHAPTER QUIZ
3. A V-6 is being checked for starter amperage draw.
The initial surge current was about 210 amperes
and about 160 amperes during cranking.
Technician A says the starter is defective and
should be replaced because the current flow
exceeds 200 amperes. Technician B says this is
normal current draw for a starter motor on a V-6
engine. Which technician is correct?
a)
b)
c)
d)
Technician A only
Technician B only
Both Technicians A and B
Neither Technician A nor B
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
CHAPTER QUIZ
4. The instant the ignition switch is turned to
the start position, _____.
a) Both the pull-in winding and the hold-in winding
are energized
b) The hold-in winding is energized
c) The pull-in winding is energized
d) The starter motor starts to rotate before
energizing the starter pinion gear
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
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CHAPTER QUIZ
5. Technician A says that a discharged battery
(lower-than-normal battery voltage) can
cause solenoid clicking. Technician B says
that a discharged battery or dirty (corroded)
battery cables can cause solenoid clicking.
Which technician is correct?
a)
b)
c)
d)
Technician A only
Technician B only
Both Technicians A and B
Neither Technician A nor B
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
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CHAPTER QUIZ
6. Slow cranking by the starter can be caused
by all except the following: _____.
a)
b)
c)
d)
A low or discharged battery
Corroded or dirty battery cables
Engine mechanical problems
An open neutral safety switch
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
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CHAPTER QUIZ
7. If the starter “whines” when engaged, a
possible cause is a(n) _____.
a)
b)
c)
d)
Worn or defective starter drive
Defective solenoid
“Open” pull-in winding
Worn leather armature break
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
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CHAPTER QUIZ
8. If the clearance between the starter pinion
and the engine flywheel is too great, _____.
a) The starter will produce a high-pitched whine
during cranking
b) The starter will produce a high-pitched whine
after the engine starts
c) The starter drive will not rotate at all
d) The solenoid will not engage the starter drive
unit
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
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CHAPTER QUIZ
9.
A technician connects one lead of a digital voltmeter to the
positive (+) terminal of the battery and the other meter lead
to the B terminal of the starter solenoid and then cranks
the engine. During cranking, the voltmeter displays a
reading of 878 mV. Technician A says that this reading
indicates that the positive battery cable has too high
resistance. Technician B says that this reading indicates
that the starter is defective. Which technician is correct?
a)
b)
c)
d)
Technician A only
Technician B only
Both Technicians A and B
Neither Technician A nor B
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458
CHAPTER QUIZ
10. A vehicle equipped with a V 8 engine does not
crank fast enough to start and sparks are
observed at the negative terminal of the battery
during cranking. Technician A says the battery
could be discharged or defective. Technician B
says that the negative cable is loose at the
battery. Which technician is correct?
a)
b)
c)
d)
Technician A only
Technician B only
Both Technicians A and B
Neither Technician A nor B
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
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END
Automotive Electricity and Electronics, 2/e
By James D Halderman
© 2009 Pearson Education, Inc.
Pearson Prentice Hall - Upper Saddle River, NJ 07458