Guide to choosing and installing starter motors

Guide to choosing and installing starter motors

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Starter Motor Basics


  • The primary purpose of the starter motor is to turn the engine over in order for the ignition to commence and the engine to start.

  •  The engine system includes battery, starter motor and ignition switch.

  • The starter will always need to engage the flywheel on the rear of the engine in order to turn the engine.  The flywheel is a large wheel with teeth around the circumference and is attached to the rear of the crankshaft.

  • Generally the start will be installed on either bottom-side of the engine with the gear end facing rearward toward the flywheel.  Some vehicles have the starter attached to the top rear of the engine under the intake manifold.

The battery supplies electricity to the starter to engage and turn over the engine.  When current from the starting battery is applied to the solenoid, usually through a key-operated switch, the solenoid engages the fork lever that pushes out the pinion on the armature shaft and meshes the pinion with the starter ring gear on the flywheel of the engine.

 

Things you should check before replacing a starter motor –


IS IT A DEAD BATTERY OR STARTER MOTOR PROBLEM?

A discharged or dead battery is one of the possible reasons a car will not start.

Sometimes, if the battery is old, it could just die one day, even if the day before it was OK.

 In either case, if the battery is low on charge, it won’t have enough power to turn over the engine:  you may hear some clicking noise or the starter may turn very slow when attempting to start the engine.

NO LIGHTS ON THE INSTRUMENT PANEL

If you turn the ignition on and no lights come on at the instrument panel it means that there is no power coming from the battery.   It could be a dead battery or often a faulty ignition switch could cause this.

Turn the headlights on, if they work, means the battery has power, so the problem could be with the ignition switch or wiring between the ignition switch and battery.

 If no lights coming on in the dash and no other electrical consumers work, the battery could be completely dead or there is no connection between the battery and the vehicles electrical system.

THE CHECK ENGINE LIGHT DOES NOT COME ON

When you turn the ignition ON before starting the car, the “check engine” light is supposed to come on indicating that the engine computer (ECM / PCM / ECU) is powered on.

If the “Check engine” light does not come with the ignition ON, it is possible that here is no power coming to the engine computer (e.g., due to a broken wire, faulty main relay, burnt fuse, etc) or that there is a problem with the engine computer itself.

I CAN HEAR A CLICK BUT THE ENGINE WONT START

It is a very common problem: you turn the key to “Start” position, but the engine won’t start; all you hear is a single click or repeated clicking.

Very often this could be caused by a weak battery or poor connection at the battery terminals.

Sometimes a battery cable can get corroded inside causing the same problem.

 In some cases a bad connection between the negative battery cable and the engine (bad ground) can cause the same symptoms.

Check the battery terminals to make sure they are not corroded.

If the battery is OK and the battery terminals appear to be clean and not corroded, the starter solenoid, battery cables or the starter motor itself could be the problem.

THE ENGINE STARTS VERY SLOW AND WON’T START

This also might be caused by a weak or discharged battery.

 If the battery is OK, the battery cables could have a bad connection at the terminal or the starter motor could have a fault.

 Sometimes, the starter motor armature bushings wear out and the starter armature rubs against the field coils inside the starter motor; this will also cause the starter motor to start very slow.

If this is the case, the starter motor will need to be replaced.

THE ENGINE STARTS PROGRESSIVELY SLOWER, THEN JUST CLICKS

If the engine starts slower and slower until it just clicks, it means the starter motor does not have enough power to turn over the engine.

Once again, a very weak battery is the most common problem in this case.

A faulty starter motor can also cause this, plus poor connection or corrosion at the battery terminals can also be the cause.

If the battery is old, you will need to look at replacing it with a new one.

IF THE BATTERY CHECKS OUT OK, BUT THE STARTER STILL WON’T START, THERE COULD BE A NUMBER OF POSSIBLE REASONS.

-The starter motor or solenoid could be faulty

-A starter solenoid wire could have a bad connection.

-A neutral safety switch is faulty.

 

The best thing you can use to make sure you replace your starter motor with the right replacement is to use the reference number that is usually stamped on the part. If you have the reference number, drop us a line at parts@myautoparts.com.au and we can match your original starter or alternator to a replacement.