Deck 9: Cranking Systems

Question 1

Which starter solenoid winding has the greatest number of turns?

A) pull-in windings
B) hold-in windings
C) they usually have an equal number of turns

Answer 1

C

Question 2

When a diesel engine fails to start after 30 seconds of cranking,what is the recommended cool down period before cranking the engine again?

A) 30 seconds
B) 60 seconds
C) 2 minutes
D) 10 minutes

Answer 2

C

Question 3

What should be regarded as the maximum cranking time before resting a starter motor and allowing it to cool?

A) 15 seconds
B) 30 seconds
C) 1 minute
D) 2 minutes

Answer 3

B

Question 4

When measuring voltage loss through a length of starter cable,what is the maximum permitted voltage drop?

A) 0.1 V-DC
B) 0.2 V-DC
C) 0.3 V-DC
D) 0.5 V-DC

Question 5

When performing voltage drop testing through the ground circuit of a starter motor you record a voltage loss of 0.4 V-DC.What should be done first?

A) Nothing,this is within specifications
B) Check for high resistance ground connections
C) Replace the starter motor
D) Check for high resistance insulated connections

Question 6

When measuring voltage loss through a starter connection terminal,what is the maximum permitted voltage drop?

A) 0.1 volts
B) 0.2 volts
C) 0.5 volts
D) 1.0 volts

Question 7

Which of the following cranking circuit faults could cause slow cranking?

A) weak batteries
B) high viscosity engine oil
C) corroded starter relay connections
D) all of the above

Question 8

Which of the following is a disadvantage of a 42 MT starter motor?

A) produces less torque than a 39 MT
B) heavy
C) will not crank high compression engines
D) all of the above

Question 9

What is the approximate reduction ratio between armature shaft and output speed of a 39MT starter motor?

A) 1:1
B) 2:1
C) 3.5:1
D) 10:1

Question 10

Which of the following statements about a starter solenoid pull-in and hold-in windings is true?

A) pull-in windings have more winding turns than hold-in windings
B) pull-in windings use a heavier gauge than hold-in windings
C) hold-in windings permit higher current flow
D) hold-in windings are energized for less time during a cranking cycle

Question 11

When performing voltage drop testing on cranking circuit components on a 12-volt chassis,which DMM V-DC range would provide accurate results?

A) 0 to 0.100 V-DC
B) 0 to 2 V-DC
C) 0 to 10 V-DC
D) 0 to 20 V-DC

Question 12

When measuring voltage loss through a starter solenoid,what is the maximum permitted voltage drop?

A) 0.1 V-DC
B) 0.2 V-DC
C) 0.3 V-DC
D) 0.5 V-DC

Question 13

A cranking current test on a diesel engine indicates low current draw.Which of the following faults would NOT be responsible for low current draw?

A) partially discharged batteries
B) low viscosity engine oil
C) high resistance in the ground circuit
D) high resistance in the insulated circuit

Question 14

When performing voltage drop testing through the cranking circuit insulated circuit,what is the usual maximum voltage drop considered to be acceptable?

A) Less than 0.2 volt
B) Less than 0.3 volt
C) Less than 0.5 volt
D) Less than 1.0 volt

Question 15

What does a 39MT starter motor use to produce high output torque combined with light weight?

A) parallel wound armature
B) planetary gearset
C) fluid torque converter
D) aggressive pinion gear tooth pitch

Question 16

Technician A says that the best method of locating high resistances in a cranking circuit is by using voltage drop testing.Technician B says that using an ohmmeter can locate high resistance starter cable.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 17

Which of the following statements about current flow in a typical truck diesel engine starter motor are true?

A) field coils are connected in series with the armature windings
B) magnetic North and South field windings are wound in opposite directions
C) all current flow though the field windings passes through the brushes
D) all of the above

Question 18

When does an energized diesel engine cranking motor produce peak torque?

A) At close to stall RPM
B) At the equivalent of 225 engine rpm
C) At maximum cranking motor rpm
D) After 15-seconds of cranking

Question 19

What is the function of the overrunning clutch in a starter drive assembly?

A) prevents starter motor damage from overspeed when the engine starts
B) overruns until the starter produces enough torque to start the engine
C) governs starter motor speed during cranking
D) limits engine rpm during cranking

Question 20

When the ignition switch is closed,which of the following should happen first?

A) cranking current flows through the control circuit
B) the hold-in windings are energized
C) the coil in the starter relay is energized
D) the engine shuts down

Question 21

When the cranking circuit is energized in sub-zero conditions,the engine turns over slowly and unevenly.Which of the following would be the most likely cause?

A) defective starter relay
B) defective starter solenoid
C) gelled engine oil
D) stripped flywheel ring gear

Question 22

Technician A says that a neutral safety switch is designed to open circuit when a transmission is in Park range.Technician B says that a neutral safety switch is designed to close when the transmission is in neutral.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 23

Technician A says that when placing an inductive pick-up clamp onto a starter cable,the arrow must point to the correct direction of conventional current flow.Technician B says that high current flow can be produced by an open in the starter motor field windings.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 24

When used,where is a starter safety switch likely to be located?

A) standard transmission
B) automatic transmission
C) either a standard or automatic transmission
D) ignition key

Question 25

Technician A says that the starter motor used to crank diesel engines can draw up to 400 amps of current.Technician B says that high resistance on the insulated side of a starter motor circuit would cause higher than specified starter motor current draw.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 26

What percentage of starter motors returned under warranty are tested to perform to specification by the OEM?

A) 100%
B) 80%
C) 50%
D) 30%

Question 27

When a cranking circuit is energized,a series of rapid clicks is heard with a no-crank condition.Technician A says that this could be caused by discharged batteries.Technician B says this could be caused by corrosion on the starter insulated terminal.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 28

When using a carbon pile to load test a battery,which of the following should occur as you turn the control knob clockwise?

A) resistance reading increases
B) current reading increases
C) voltage reading increases
D) voltage and current readings increase

Question 29

What should be used to clean a dirty commutator in a disassembled starter motor?

A) general purpose emery cloth
B) right-angle grinder
C) sandpaper with #100 grit or less
D) sandpaper with #400 grit

Question 30

Which of the following connects the cranking control circuit with the starter motor high current circuit?

A) ignition switch
B) starter button
C) starter relay
D) starter solenoid

Question 31

If a heavy duty starter motor appears to spin when energized but the engine does not turn,which of the following could be at fault?

A) worn pinion gear
B) stripped flywheel ring gear
C) defective starter drive assembly
D) all of the above

Question 32

If you are bypassing a starter relay switch using a jumper wire,what component is being tested?

A) starter solenoid
B) ignition key
C) battery bank
D) starter relay/ mag switch