Starter Motor: The Ultimate Guide with 24 Q&A

The starter motor plays a very important role in the car starting system. In this guide we will explain you all aspects of Starter Motor by 24 Q&A

Some of the topics that will be covered include:

What is a starter motor? Where is it located? How does it work?

Which is the best starter for my vehicle?

How can it be fixed should it have a problem?

Can I fix the starter motor or should I always call in an expert?

And how do I maintain the starter motor among others.

mzw-starter-motor

This is a long article over 4.5k words, I divided into 5 parts for easy reading, please click below part number to jump to each starter motor guide.

Part 1: What is a Starter Motor

Part 2: Inside of a Starter Motor

Part 3: Starter Motor Type

Part 4: Starter Motor Troubleshooting

Part 5: Fix A Starter Motor

Part1

What is a Starter Motor

In this part we will have an simple look at the car starter motor. At the end of the part, you will have known what a starter motor is, how it looks like, where it is located and how it works to start the engine.

 

Starter Motor Questions List

Q #1. What is a starter motor
Q #2. Where is the starter in a car?
Q #3. How does a starter work?
Q #4. How a starting system works

 

Q #1. What is a starter Motor

what-is-a-starter-motor

A starter also commonly referred to as a starter motor is an electronic device that is used to enable the engine start working on its own power.

This is because the engine needs to attain some speed for it to work. The starter therefore helps the engine to attain the intended speed to run the car. After it is done, the starter is no longer useful and thus turns off.

 

Q #2. Where is the starter in a car?

 

starter-motor-location

A car starter location varies depending on the car model and design. However most of them are normally located under the vehicle close to the engines back where the engine meets with the transmission.

It is interesting to note that most people do not know where the starter is located because it is rarely replaced. In most cases the starter motor is replaced only once in a cars’ lifetime. It is actually applauded as one of the most reliable parts in a car.

Depending on its location, the starter can be removed either from the hood or by getting under the car.

 

 

Q #3. How does a starter work?

 

As mentioned above the main task of a starter is to enable the engine acquire a certain speed for it to function.

To do this, the starter uses power which is acquired from the car battery. It is turned on using an ignition key where the current is passed on to the starter solenoid attached to it. The starter solenoid then completes the circuit and energizes the starter motor.

The starter gear also referred to as a Bendix gear is then pushed forward to mesh with the engine flywheel which is attached to the engine crankshaft.

The shaft is turned by the starter motor spins allowing the engine to start. Having accomplished its main purpose, the starter goes off.

 

 

Q #4.How a starting system works

start_circuit

The starting system starts working the moment you turn your car ignition key to the start position. The battery power then goes through the control unit of the starter activating the starter solenoid in the process.

Once the starter solenoid is activated, it energizes the starter motor while at the same time pushing the starter engine gear forward where it meshes with the engine flywheel which is attached to the engine crankshaft.

The starter motor then spins rotating the engine crankshaft which in turn allows the engine to start.
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Part2

Starter Motor Components - Inside of a Starter

After part1, you must know what is a starter motor now.

Then it’s time turn you be a half-expert.

We will explore all the parts of a starter.

You will get to see and know the parts, as well as read on how each part works to achieve the overall objective of starting the engine.

inside-of-a-starter-motor-mzw-blog

There are 5 main parts inside of a car starter motors namely:

 

Q #5. What is a starter solenoid?

what-is-a-starter-solenoid

A starter solenoid is a very important part of the car starting process. It is a part of the car system that relays powerful electric current to the starter motor.

When a car is switched on, it sends large electric current to the starter motor and helps it to start hence starting the entire vehicle.

 

Q #6. How does a starter solenoid work

starter-solenoid-operation

The starter solenoid accomplishes its task by closing an electric circuit and sending electric power from the battery to the starter. The amount of power needed for this process is normally large and the solenoid is able to handle it.

Also, the starter solenoid starter makes it possible for the starter to turn on the engine by pushing the gear forward where it eventually links up with the engine flywheel.

The motion is normally very fast to ensure that the engine takes up motion and runs. Once the engine is running the starter motor goes off.

 

Q #7. What is a starter motor bendix drive

starter-bendix-drive-mzw-blog

Named after the person who invented it, a starter motor bendix drive is an engagement mechanism.

It enables the pinion gear to either engage or disengage the flywheel once the starter is switched on. This in turn allows the engine to start.

Once the engine starts the motor bendix drive disengages.

 

 

Q #8.How does a starter bendix work

The starter bendix meshes with the flywheel once the ignition is turned on. It then withdraws with the release of the ignition key once the engine starts.

Its main function is to ensure that the starter engages with the flywheel that is essential for the engine to start.

 

 

Q #9. What is starter armature

starter-armature-mzw-blogThe starter armature is an electromagnet that is fixed on the drive shaft.

It is wrapped with numerous conductors made of a metal ore that allows current to pass through it.

The armature has an axle with the commutator attached to provide a magnetic field that rotates it.

 

 

Q #10. What is a starter field coil

starter-field-coil-draw-mzw-blog

Just as the name suggests this is a part of the starter motor that consists of field coils. These field coils are converted to electromagnetic force through the battery energy which then turns the armature.

The armature is turned on when the magnetic field created pushes it from the left magnet to the right one and vice versa through north and south magnetization thereby causing rotation.

 

 

Q #11. What is a starter carbon brush

starter-carbon-bush-mzw-blog

This is a part of the starter that conducts electricity to the starter motor through the commutator.

Because of their nature, the carbon brushes wear out with time. It is therefore important to constantly ensure that they are checked and replaced before they can cause any damage to the commutator.

When they are worn out, they cease to conduct power to the commutator. This in turn affects the starter motor and it stops running eventually affecting the performance of a car engine.

 

 

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Part3

Starter Motor Types

This part may unfamiliar to the most reader(If you are not interested, click here), however if you are a starter motor dealer, you must heard PMGR, PLGR or DD Starter.  Read on to know the different types, understand their functionality and why you ought to choose one instead of the other. You will also get to know how they look like through the pictorial illustration.

 

There are 5 main types of car starter motors namely:

 

Q #12.What is DD starter?

DD – Direct Drive Starter Motor

 dd-starter

The direct drive starter motor also referred to as the DD is the most common starter motor type. It is a solenoid operated unit that comes in different applications and construction design.

However, despite these, the principle of operation for all solenoid operated starter motors remains the same.

When the ignition is switched to the START position, the solenoid is energized by the control circuit from the car battery and in turn moves and its plunger to pivot the shift lever.

The lever then directs the pinion gear which meshes with the engine flywheel. This causes the starter motor to spin. The spinning motion is transferred to the flywheel attached to the crank shaft eventually turning the engine until it runs on its own.

At this point you let go off the key moving the starter gear away from the flywheel.

 

 

Q #13. What is PLGR starter?

PLGR – Planetary Gear

 plgr-starter

Also known as PLGR, planetary gear motor starters are part of the permanent magnet starter motors that are quickly replacing the direct drive ones.

This starter motor transmits power between the pinion shaft and the armature. This enables the armature to spin with more speed and torque.

The PLGR is manufactured with an aim of reducing gear which further reduces the demand for high current. Its assembly consists of a sun gear located at the end of the armature.

Three plenary carrier gears are also found inside the ring gear which is held stationery.

It is important to note that by holding the ring gear and inputting the sun gear while outputting the carrier, the planetary gear is able to achieve a great amount of gear reduction.

 

 

Q #14. What is PMGR starter?

PMGR – Permanent Magnet Gear Reduction

 pmgr-starter

This starter type has been manufactured to provide and designed with less weight, easy construction and less heat generation.

Instead of field coil starters, the permanent magnet gear reduction starter motor type commonly known as PMGR uses four to six magnet field assemblies.

It is activated through a 12V solenoid that has three terminals and is heavy duty allowing it to draw less current. Due to lack of field coils, the commutator and brushes deliver current directly to the armature.

PMGR starter should be handled with care especially the permanent magnets which are brittle and cab be easily destroyed.

 

 

Q #15. What is PMDD starter?

PMDD – Permanent Magnet Direct Drive

 pmdd-starter

This starter type is similar to the direct drive starter motor in many ways. The only major difference is that instead of field coils, this starter has permanent magnets.

 

 

Q #16. What is OSGR starter?

OSGR –  Off-Set Gear Reduction

 osgr-starter

This starter type is designed to work under high speed and low current. It is lighter and more compact making it easy to assemble.

It also increases cranking torque making it common among the four wheel drive vehicle.

This starter is light weight making it among the most purchased brand for vehicles that have high speed with high cranking toque.

 

 

Q #17. What is Inertia starter?

 inertia-starter

The inertia type starter motor is also an electric starter motor that achieves all the required operations of a starter effectively by having a threaded sleeve and toothed opinion.

This enables the starter to crank the engine eventually starting it without destroying any motor parts. Its unique features enable it to achieve high cranking speed meaning that the engine starts strong and very fast.

It is also able to minimize the amount of weight associated with the torque capacity of the starter.
While all these starter types are still in use, it is important to note that the Direct drive starter motors are slowly being replace by the other motors.

This is because of their large size, high current requirements and heavy weight.

The starters in the market are continuously being improved to compatible sizes with more power and low current requirements.

 

 


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Part4

Starter Motor Troubleshooting

At any one time you are bound to face some minor problems with your starter motor. This is because for an engine to start, a certain level of force is required.

With time the rotation force can cause some technical errors to the starter motor. As a result, you may find yourself unable to start your car. In some instances, the engine might have some slight cranking but with very minimal power hence a false start.

In other cases, the engine will remain silent without any sign of starting. If you are experiencing any problem with your starter motor, then this part should come as a relief.

You will actually be surprised to know that you can easily manage most of the problems on your own as they are not as technical as you may have previously believed.

Below are simple procedures that will help guide you to the best way that you can troubleshoot your starter motor on your own and save on costs to the mechanic.

 

Starter Motor Questions List:

Q #18. How to test/check car starter

Q #19. How to diagnose starter problems

Q #20. How much for a starter motor replacement

Q # 21.How much is a starter motor & Labor Cost

Q # 22. Which starter motor – OEM vs Aftermarket vs Rebuilt Starter Motor 

Q #18. How to test/check car starter

 how-to-test-car-starter-mzw-blog

The first and foremost step in troubleshooting the car starter motor is to identify the problem. Whether the engine you should be in a position to know when your engine is fine or not.

There are a few common symptoms that indicate a problem with the starter motor. These include:

  • The engine not turning over once the ignition key has been turned on.
  • A loud click when you turn over the engine and nothing else after that. In this case the engine does not start.
  • You turn on the engine but it starts very slowly then stops
  • Jumpstarting a vehicle to no avail.

When you experience the above then it means that either the starter motor is not working or the starter system has a problem.

 

Once you are sure that your starter has a problem then you need to find out what exactly is causing it not to work. Could it be a systematic problem or is the starter faulty?

 

Here is how to find out:

 

Step #1. You need to ensure that the battery is functioning well. This is done through a simple multimeter test.

Step #2. Test on whether the starter motor is receiving enough power from the battery

Step #3. Then test whether the starter motor is receiving the signal to start from the ignition switch.

Step #4. Carry out a voltage drop test on the starter battery and ground circuits.

Step #5. Try and turn the engine by hand. This will help you to eliminate a locked-up engine or A/C compressor

Step #6. Bench test the starter motor.

 

The location of the starter motor could make the testing process slightly difficult. While some vehicles have it in the front where it is easy to view and physically access, some starter motors are hidden in the back if the engine. However, regardless of its location, the tests are similar. You will have to undertake precautionary measure to ensure that you are safe when carrying out the tests.

 

*Safety guidelines when testing the starter motor

  • If you have to lift the motor vehicle to access the starter, use the jack-stands to support the car
  • Use safety glasses when you are underneath the car to protect your eyes
  • Get a helper to crank the engine when you’re performing the tests
  • Ensure that you don’t short-to-ground your jumper wire when jumpering 12V to the S circuit.
  • Use common sense to stay alert and safe.

 

 

Q #19. How to diagnose starter problems

starter-motor-diagnose

Having identified the possible problem, the next step is to carry out troubleshooting. At this stage it is important to be aware of the level of the problem. This way it is easier to decide you can handle it or you need to bring in an expert.

 

1)  Engine not turning

This could be caused by different problems.

  • Insufficient power supply

This is one of the most common problems with the starter motors. While some starter motors run on direct power supply, some run on battery. You need to check on whether the battery is in good condition and able to provide the required amount of power to the motor. Rechargeable batteries need frequent maintenance and regular checkup. A multimeter is used to check on the amount of voltage from the battery.

Some of the issues that could hinder the performance of a battery include corrosion on the battery terminals and loose or broken terminals.

 

In this case replacing the battery terminals solves the problem and the starter will continue working perfectly.

  • Bad Ignition switch/Bad neutral safety switch.

When you are sure that the battery is in good condition, this could be the other reason why starter is not getting enough power.

To solve this you can manually get the power to the start jumpering 12V to the S circuit.

This will automatically get the required energy to the starter which will in-turn start the engine.

 

  • Voltage Drop

This occurs when there’s obstruction on the flow of power to the starter which in turn reduces or entirely cuts off power. This in turn makes it difficult for the starter to crank the engine.

The culprit in such a situation is the corrosion of the battery terminals.

In this case, you only need to clean the terminals or replace them altogether and you will have your engine running as it should.

 

2)Too much noise

This is also another problem that is common with the starter motors. When you turn on the ignition, the engine starts but makes a lot of noise.

If this is the case, it is an indication that you need to lubricate your starter motor.

A few drops of machine oil often come in handy.

However, in some cases a noisy engine could be an indication of more critical issues. The starter may need cleaning and greasing.

 

In some cases, you may need to replace the starter. It is therefore very important at this point to seek expertise opinion.

 

 

Q #20. How much for a starter motor replacement?

There are many factors that determine the cost of a starter motor replacement. They include the car model, your area of residence and the manufacturers’ recommended parts. However the overall cost range anything between $200 and $500.

 

 

Q # 21.How much is a starter motor & Labor Cost

The overall cost of the starter motor is determined on whether you need a new gear ring or not. If you do not need a gear ring the starter motor costs between $100 to $500 depending on the model and year of the car. On the other hand if you need to replace the entire fly wheel, you will need to add up to $200.

The labor costs are also determined by the area and model of the car. Most of the replacement labor costs range between $150 and $350.

 

 

Q # 22. Which starter motor – OEM vs Aftermarket vs Rebuilt Starter Motor

oem-starter

Whenever you want to replace your starter motor you will come across these three terms that describe them. It is important to understand what they mean to enable you make an informed decision.

When you purchase a vehicle it comes with parts that were fitted during production. These parts are known as genuine parts or original equipment. However, whenever you need to replace them you have several parts to chise from. This applies even in replacing starter motors. You can either replace using:

 

Original Equipment Manufacturer starter motors (OEM) – these starter motors are manufactured by the same producers of the original equipment. However, they are made specifically for replacement and hence are packaged differently. Additionally, they are sold under the company’s name as opposed to the vehicle brand name. Nonetheless, the starter motors are similar to the genuine ones and are of similar quality though a little cheaper(But more expensive than the below types).

Aftermarket starter motor – These starter motors are made by companies who specialize in making replacement parts but do not sell to vehicle manufacturers. Although the quality is not as high as the original/genuine starter motors, they equally perform well and are functional.

Rebuilt starter motors – just as the name suggests, these are starter motors that have been taken apart, cleaned and gone through the inspection process after which they are rebuilt. They are then tested to ensure that they perform according to expectations.

 

Having understood the above, the decision in which is the best starter motor to use can be easily determined. The OEM starter motors are highly recommended to vehicles that are upto five years old. This is to ensure that you do not interfere with the warranty. After that you can then consider the other starter motors. The aftermarket starter motors come in handy because they give you the ability to choose from a wide range of brands and quality as well as bring down the cost of replacement.

 

 


More  Resource:

Test a Starter Solenoid

Starter Troubleshooting

Starter Won’t Start

Starter Troubleshooting Tips

Part5

Fix a Starter Motor

Starter Motor Questions List:

Q #23. How to replace a starter motor

Q # 24.  How to rebuild a starter motor

 

 

Q #23. How to replace a starter motor

starter-motor-replace

Having determined that your starter motor is the problem, it is now time to replace it. Often times, the starter is located on the lower side of the vehicle except in a few motor vehicles where the starter can be accessed from above.

This means that you have to be prepared for a considerable amount of dirt. You therefore need to be dressed appropriately. Additionally, you need protective eye wear as you will be working underneath hence there will be flakes of dirt and rust dropping directly above your head.

 

First and foremost you need to ensure that the car has cooled off and that the wheels are steady. You should then use sturdy Jack Stands to lift the car a foot or so. This will give you adequate space beneath the vehicle.

The next step is to disconnect the battery from the starter. You will do this by removing a fat wire that connects the two. It is important to ensure that you have the right wires so that you do not interfere with the car system especially where the car has an external solenoid, or it is the older type that might have additional wires.

You will then remove bolts holding the starter to your car block. To make it easier, you may need to remove the sheet metal cover. However, you should be careful not to drop the starter on your head as you work on the final screw because it is quite heavy.

Before you get out from beneath the car, it is advisable to mark at least one tooth on the ring gear and inspect the teeth. This will enable you to know whether they have been damaged or not. You will also be able to assess the extent of the damage. If the damage is severe you will need to replace the flex plate or the flywheel thus saving on thousands of dollars that could be used in replacing other parts and a ring gear should the starter completely damage the teeth.

Once you have your starter motor out, you should take it with you to the store for exchange. Note that the replacement could have very few similarities with the original part thanks to the transition of motor starters to more compact and light weight starters that are having higher-speed with the ability to turn the engine faster and use less current. They are also well appropriately greased hence no need for any further lubrication.

 

Placing the new starter is relatively easy. You only need to screw the bolts, reinstall the braces and heat shields and the reconnect the wiring. You will then reconnect the battery, ease the vehicle off the jacks and start it and you are good to go.

 

 

Q # 24.  How to rebuild a starter motor

Purchasing a new starter can cost up to $300, even $400. It therefore comes as a relief to know that you can save on costs by rebuilding your own starter. This is particularly easy because all starters have the same design basically with a slight difference in the housing for the different models. It is therefore important that you get the right parts.

 

The most common wear parts of the starter motor are:

  • Bushings – normally 3 in total and cost about $1 each
  • Brushes – 4 of them costing between $15 and $45 depending on whether they have brushes readily mounted or not.

 

Process:

The first step is to disassemble the starter motor. When starting off begin by looking out for a set of marks on the body of the starter. They come in handy when reassembling it.

Next remove the O-ring and dispose it off as you will not be reusing it. then turn the motors’ armature shaft and unbolt the stud on the back. Ensure that the nut and the other accessories that come off the terminal are well kept.

Loosen the two nuts holding the solenoid to the front housing. This brings to your view another O-ring that holds the starter motor and the housing together. Carefully separate the starter motor and the housing keeping this o-ring well as you will be using it during reassembly.

Remove the two nuts that hold the starter motor together. You will also remove the motor’s front cover and detach the o-ring and discard it.

Once you do this, carefully examine the condition of the bearing in the rear cap and determine on whether you will need to replace it or not based on the level of damage. If it feels bumpy or turns roughly it means that you need to replace it.

Remove the armature from the starter body.

 

Armature Inspection

starter-armature-inspection

This is done in order to determine if there is any abnormal wear or damage. When doing this it is important to keep track of the shims on the commutator. This helps you to return everything in the right place once you are done.

Some of the inspection arrears on armature inspection include service limit, resistance, mica depth among others. Should any of these areas be found wanting, then there is need to replace the armature.

There are however some problems such as the mica insulator that can be cleaned without necessarily having to replace the armature.

 

Brush Holder

In most cases the brush holders are fixed on the plate in the rear cover. To remove them, you carefully remove the terminal post from the body, together with the brush holder.

To know the efficiency of the b rushes, you measure the working length of the brush and make a comparison with the required length as specified for your vehicle. This will guide you on whether to replace or not.

Assembly

Once you are done checking all the above and undertaking the necessary replacements, it is time to reassemble your starter motor.  You will begin by inserting the armature into the starter motor body.

You will then insert the rear cap with a new o-ring. A new o-ring should also be put on the front cover.

Next, install any lock rings and shims into the cover ensuring that the alignment marks are matching. Insert the o-rings to the screws and slide them into the position. Tighten the screws to the desired tightness and install the starter motor.

 

 


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Conclusion

From the above, it is clear that while the starter motor plays a critical role for the engine to run, it is not a complex car part. It is not only easy to identify but also easy to maintain and troubleshoot.

Additionally, you can also be able to fix or rebuild one should yours fail.  It is also now clear that you can save a lot of money in repairs. Understanding your car starter also puts you at a better place when dealing with mechanics because you are aware of the dynamics involved especially in purchasing the different motor starter parts.

 

 

If you are a starter motor dealer, feel free to contact our technical team for assistance.