Checks; Starter Motor Operational Fault Diag­nosis - Fiat Brava Service Manual

Electrical equipment
Starting
55.
CHECKS
The starter motor components should be subjected to the tests listed below:
rotor: contintuity test, short-circuit and insulation to earth
stator: continuity test and insolation to earth
brush holder support: insulation to earth '
solenoid valve: continuity test and insulation to earth
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Each time the starter motor makes noises during starting, the pinion /free wheel must be re­
placed.
STARTER MOTOR OPERATIONAL FAULT DIAGNOSIS
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1. The motor does not rotate •
The cause may be: \ /
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- the battery terminals are oxidized;
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- starter motor supply cable terminal slack;
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- starter motor supply cable terminal broken or oxidized;
- battery completely discharged;
- lack of contact for rotor arms at commutator;
- positive rotor arm short circuited;
- starter switch contacts oxidized, worn or insulated through fragments;
- rotor or inductor to earth;
- rotor or commutator centrifuged;
- pinion engagement solenoid winding broken or to earth.
2. The motor rotates very slowly
The cause may be: ' \
- commutator brushes and blades worn;
- part of inductor or rotor winding coils short circuited;
- battery terminals oxidized;
- battery state of charge very low or one or more elements deteriorated.
3. Excessive noise during starting
The cause may be:
- pinion free wheel mechanism worn;
- poor alignment between motor and flywheel ring gear;
- several flywheel ring gear teeth excessively worn on the engagement side;
- speed reduction gear defective or excessively worn.
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