Five problems with starters and alternators

Febi discusses five common problems with starter motors and alternators and how to proceed with each issue.

Starter issues

Problem #1: The starter does not rotate the crankshaft

Cause

• The battery is nearly discharged

• Blown fuse

• Electromagnetic starter motor relay contact switch malfunction

• Starter motor malfunction

• Mechanical problem in the engine

Solution

• The battery condition needs to be checked and replaced as necessary

• Fuse has to be replaced

• The electromagnetic relay has to be replaced

• The starter has to be replaced

• The condition of the engine has to be checked

Problem #2: The starter rotates the crankshaft too slowly

Cause

• The battery is nearly discharged

• The wiring harness or battery cables may be loose and/or corroded

• Poor connection in electromagnetic contact switch

• Starter motor malfunction (worn out brushes)

Solution

• The battery charge level must be checked and recharged or replaced as necessary

• Wiring harness and battery cables have to be checked and replaced as necessary

• The electromagnetic relay has to be replaced

• The starter has to be replaced

Problem #3: The starter rotates but it does not turn the crankshaft

Cause

• Damaged/worn out starter pinion or flywheel ring

• Damaged starter bendix

Solution

• The condition of the pinion has to be checked

• The starter has to be replaced

Problem #4: The starter does not stop rotating

Cause

• Damaged/worn out starter pinion or flywheel ring

• Damaged electromagnetic switch

• Damaged or faulty ignition switch

Solution

• The condition of the pinion has to be checked

• The starter has to be replaced

• The condition of the ignition switch has to be checked and replaced as necessary

Problem #5: Excessive noise coming from the starter

Cause

• Worn out bush

• Pinion worn

Solution

• The condition of the starter has to be checked

• The starter has to be replaced

Starter Motor Diagram Components:

• Solenoid

• Armature

• Brush Holder

• Field Coils

• Reduction Gear Housing

• Engaging Shift Lever

• Lock Ring

• Pinion Drive

• Stop Collar

Alternators

Problem #1: Control light doesn’t appear after ignition

Cause

• Defective light or bulb

• Loose wiring harness or battery cables

• Damaged or defective voltage regulator

Solution

• The light and/or bulb should be replaced

• Wiring harness or battery cables require checking and repairing

• The alternator has to be replaced

Problem #2: The battery does not charge

Cause

• Faulty battery or damaged battery cables and/or fixings

• Faulty alternator

Solution

• The battery and cables have to be checked and replaced if necessary

• The output voltage has to be checked

• The alternator has to be replaced

Problem #3: The battery is continuously overcharged

Cause

• Faulty battery

• Defective voltage regulator

Solution

• The battery has to be replaced

• The alternator has to be replaced

Problem #4: Intermittent battery charging

Cause

• Loose drive-belt

• Faulty rectifier

• Damaged windings

• Faulty regulator

Solution

• Check drive-belt tension and adjust, or replace the drive-belt as necessary

• Check all fixings and tensioner

• The alternator has to be replaced

Problem #5: Excessive noise

Cause

• Loose or worn out drive-belt

• Worn bearings

Solution

• The drive-belt tension has to be adjusted, or replace the drive-belt as necessary

• The alternator has to be replaced