Faulty Starting System Symptoms
• No Cranking
• Slow Cranking
• Abnormal Noise
• Overheating of Cables
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Engine does not crank (Solenoid or relay does
not click)
• Dead battery
• Loose, corroded or broken connections
• Corroded battery terminals (lights will usually
light)
• Faulty ignition switch
• Faulty neutral safety switch or clutch switch (To
test: push on brake pedal, hold key in start
position and move shift lever or clutch pedal)
• Defective starter switch, relay or solenoid.
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Engine will not crank (Solenoid or relay clicks)
• Low or "dead" battery
• Corroded battery terminals or cables
• Defective starter solenoid or relay
• Defective starter motor (if current is passed through relay
or solenoid)
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Starter motor cranks slowly
•
Low battery
• Loose, corroded or broken connections
• Cable size too small
• Internal starter motor problems
• Engine oil too heavy
• Ignition timing too far advanced
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Starter spins, but will not crank engine
• Broken starter drive gear
• Broken flywheel teeth
• Noisy starter motor
• Starter mounting loose
• Worn starter drive gear or flywheel teeth
• Worn starter bushings
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On Vehicle Testing
• Cranking speed
• Cranking Voltage- should be > 9.6V
• Voltage Drop is indication of excessive résistance, loose
or dirty contacts
• Should be < 0.25 to 0.5V
• Current Draw – 4 cylinder engine 125-175 A max.
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Current Draw Test
• No Current draw – open circuit
• High current draw
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Short circuits
Poling
Tight bushes
Insufficient thrust clearance
Engine not turning freely
• Low current draw
– High resistance
– Burnt solenoid contacts
– Dirty/ burnt commutator and brushes
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Starter Tests off Vehicle
• Bench Test- no special tester needed
• Lock Torque or Stall Test- normally carried out after an
overhaul
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Bushes and Bearing
Check and Inspect
• Poling – armature rubbing on the pole shoes
• Bushes- for excessive
• Bearings – roughness and bumpiness (reduction gear
type)
• New bushes should be immersed in oil for one hour
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Brushes and Bush holder
• Measure brush length – it should be within the
specifications
• Check for sticky brush ( in its holder)
• Check brush spring tension
• Positive brushes must be insulated
– Infinity reading with the brush holder and brush plate
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Positive Brushes must be insulated
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Measure Brush length
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Solenoid test
Use half the rated voltage
• Pull in test
– Connect battery power to terminal S and M
– Plunger should pull in
• Hold in test
– Push the plunger in
– Connect battery power to terminals S and solenoid body
– Release the plunger and it should remain held.
• Return Test
– Plunger should return to normal position once the power is
disconnected
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Hold in Test
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Pull In Test
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Armature
• Check for burning and overheating
• Check for bend in the shaft on a ‘v’ block
• Check for poling
• Test for short circuit on a growler- blade will vibrate on the short
circuit winding.
• Test the windings for Open circuit -on the commutator segments
– Use a ohmmeter or light tester (30V)
• Test short to ground- from commutator to shaft and armature body
– Use ohmmeter
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Measure Commutator diameter
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Armature Ground test
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Commutator continuity test
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Commutator test with 42 V
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Growler test
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Armature Run -Out Test
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Field Coil
• Check for insulation damage
• Test for open circuit- between the brush and positive
terminal of the field
– use ohmmeter or test light
• Test for short to ground – field coil to the housing
– use test light
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Field Coil to Short to Ground Test
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Clutch assembly
• It should lock on one direction and turn freely in the other
direction
• Check for smooth movement along the splines.
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One way clutch test
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Armature Thrust Clearance
• Use filler gauge to measure the clearance
• If not right adjust it using shims
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Pinion Clearance
• Disconnect SM terminal from the solenoid
• Apply battery power to S and SM terminal of the solenoid
• Pinion should move out without the armature spinning.
• Check the clearance
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Pinion Clearance
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Test Bench
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