Key pointers diagnosing starter/alternator issues POSSIBLY DUPLICATED

Key pointers diagnosing starter/alternator issues POSSIBLY DUPLICATED

ALTERNATORS: Fault finder check list

Problem: Warning light remains on

Possible causes:
1. Check the fan belt is not slipping
2. Check the positive and negative supply to the alternator
3. Ensure warning light circuit is not down to earth
4. Suppressor fitted incorrectly
5. Terminals on alternator and/or wiring burnt

Problem: No warning light

Possible causes:
1. Check bulb has not blown
2. Poor or burnt connectors to alternator
3. Break in warning light circuit wiring to instruments
4. Check ignition fuse for instrumentation

Problem: Alternator undercharging

Possible causes:
1. Slipping fan belt
2. Poor earth to alternator
3. Poor supply to alternator

General Checks:
1. Ingress of oil burns out the alternator
2. Over tightened fan belt bearings become noisy
3. Wrong spacers on pulley
4. Brackets broken

STARTER MOTORS: Fault finder check list

Problem: Starter will not turn

Possible causes:
1. Poor connections to starter
2. Check positive and negative supply to starter
3. Less than 12V to solenoid exciter terminal due to worn ignition switch or broken wiring
4. Flat battery

Problem: Starter turns slowly or makes grating noise

Possible causes:
1. Vehicle timing out of specification
2. Poor supply to starter
3. Gearbox bush worn on free floating starter
4. Poor engine earth

Problem: Starter motor sticks

Possible causes:
1. Excessive clutch dust on starter
2. Worn ring gear on car
3. Ignition switch sticking and not returning

Quick test: Place starter tightly in a vice. Use a 12V battery and jump leads. Connect negative side to starter body and positive to main feed on starter. With an insulated screwdriver arc across the main feed and solenoid exciter terminal. Starter should throw in and turn at speed.

Technical help from Autoelectro
Autoelectro’s website ‘catalogue’ section lists specific technical information for many applications. All you have to do is click on the red ‘i’ that accompanies the product specifications.

Related posts