Starter Motor Systems

The purpose of the starting system is to:

Maintain battery state of charge Rotate the engine fast enough to allow it to start and run on its own Provide power to all electrical accessories Control ignition timing during normal operation

The starter motor converts:

Mechanical energy into electrical energy Electrical energy from the battery into mechanical torque at the flywheel Hydraulic energy into mechanical torque Heat energy into electrical energy

A typical starter solenoid on a light vehicle performs which TWO main functions?

Engages the pinion with the ring gear and switches high current to the motor Regulates alternator output and supplies field current Controls ignition coil dwell and timing Provides constant mesh between pinion and ring gear and charges the battery

The gear on the starter that engages with the flywheel or flexplate ring gear is called the:

Drive gear or pinion Sun gear Idler gear Ring gear

A reduction type starter differs from a direct drive starter because it:

Does not use a solenoid Uses gear reduction between the motor and the pinion to increase torque Drives the alternator through a gear train Runs only on AC current

The starter drive overrunning clutch is designed to:

Prevent the starter from turning when the key is in START Allow the engine to drive the starter after start-up without damage Increase cranking speed above the motor speed Prevent pinion engagement with the ring gear

Excessive starter current draw with slow cranking usually indicates:

High resistance in the starter circuit Weak battery connections only Internal starter fault such as a shorted armature or dragging bearings Open circuit in the solenoid windings

A 'click but no crank' condition with normal battery voltage is MOST likely caused by:

Shorted alternator diodes Insufficient current to the starter through high resistance connections Incorrect spark plug heat range Weak ignition coil output

Modern vehicles often control the starter relay using:

A direct connection from the ignition switch only The powertrain control module after checking safety inputs The alternator field circuit The headlamp switch

Neutral safety or clutch switches are used in the starting circuit to:

Increase starter torque Prevent starter engagement unless transmission is in park/neutral or clutch is depressed Reduce battery voltage during cranking Provide power to the charging system

A slow cranking complaint with heavy battery cables that feel hot after repeated cranking usually indicates:

Open circuit in the starter motor High resistance in the cables or connections Normal operation in cold weather Defective ignition switch contacts only

Starter brushes that are worn to their minimum length will cause:

Higher cranking speed and lower current draw Intermittent operation or no crank due to poor contact Only noise from the starter drive Permanent damage to the ring gear

A bench test on a starter checks:

Starter performance off the vehicle under no-load and sometimes load conditions Only the battery state of charge Alternator rectifier performance Ignition timing at cranking speed

A voltage drop test performed between the battery positive post and the starter motor B+ terminal during cranking should normally be:

0.5 V or less 2.5 V or more Zero volts exactly 10 V or greater

Maximum allowable voltage drop on the ground side of the starter circuit during cranking is typically:

0.1 to 0.2 V 1.5 to 2.0 V 5.0 V No specification is required

Compared with a direct drive starter, a gear reduction starter is usually:

Larger and heavier with lower torque Smaller, lighter and capable of higher torque Unable to crank high compression engines Used only on diesel equipment

Grinding noise during cranking is MOST likely caused by:

Weak battery Misaligned or damaged starter drive or ring gear teeth Shorted rotor in the alternator Loose accessory drive belt

The main high current path for the starter motor is from:

Ignition switch to the starter field only Battery positive through the solenoid contacts to the motor and back through the engine block and battery negative Alternator output to the motor case Instrument fuse panel to the solenoid S terminal

When replacing a starter, the parts technician must ensure that the replacement unit has:

The same paint colour and logo Correct mounting, nose housing, tooth count and electrical connections Higher voltage rating than original Fewer field coils for faster operation

Repeated starter drive failures may indicate:

Incorrect engine oil grade Improper pinion to ring gear engagement or worn ring gear teeth High charging system voltage Incorrect spark plug gap

A starter that continues to crank after the key is released from START may be caused by:

Weak battery Sticking solenoid contacts or relay contacts welded closed Low alternator output Loose drive belt

The freewheeling or overrunning function of a starter drive is MOST important:

Before the engine starts After the engine fires and exceeds starter speed During glow plug operation During alternator output test

On modern vehicles with start-stop systems, the starter motor is often designed:

With lower torque and lighter construction For increased durability and higher cycle life To operate only when the battery is low Without any solenoid engagement mechanism

Which of the following safety practices is correct when working on a starting system?

Leave the battery connected while removing the starter Support the vehicle securely if working from underneath Bypass safety switches for convenience Use undersized jumper cables to limit current

A no-crank condition with no solenoid click and no voltage at the solenoid S terminal when the key is turned to START may be caused by:

Open starter armature winding Faulty ignition switch, relay, or safety switch in the control circuit Shorted solenoid pull-in winding Seized engine

Engine cranking speed will generally:

Increase with lower battery temperature Decrease as engine oil thickens in cold weather Remain the same regardless of battery condition Be independent of starter condition

When checking starter current draw, the ammeter should be connected:

In parallel with the starter motor In series with the battery positive cable feeding the starter Between the alternator and battery Across the solenoid S terminal

High resistance at the engine ground strap between battery negative and engine block will cause:

Higher than normal cranking speed Slow or no cranking and hot ground connections Faster alternator operation No effect on the starting system

When ordering a replacement starter, tooth count on the pinion is important because:

It determines alternator output voltage Incorrect tooth count can lead to incorrect engagement and gear damage More teeth always give higher torque Fewer teeth always reduce noise

A hydraulic lock in an engine cylinder during cranking will cause the starter to:

Rotate faster than normal Labour or stop abruptly due to incompressible fluid Charge the battery more quickly Operate normally with no change

The starter commutator provides a means to:

Rectify AC output Switch current through the armature windings as it rotates Increase alternator field strength Reduce motor torque

Before disconnecting starter cables on a modern vehicle, it is good practice to:

Remove the fuel tank Disconnect the negative battery cable and follow any memory saving procedures Increase charging voltage Turn the heater fan to high

The starter field windings or permanent magnets are located in the:

Armature shaft Drive pinion Motor housing Flywheel

Repeated short drive cycles with many cold starts place extra demand on the starting and charging systems because:

The starter is not used during short trips There is little time for the alternator to replace energy removed from the battery The engine does not require fuel during these trips The ignition system is disabled