The starter motor – the heart of the ignition

A bit of history

In the automotive mechanic’s world, the starter motor is a crucial component that often goes unnoticed but plays a key role in starting a vehicle. 

The introduction of the starter motor in the realm of automotive advancements was delayed. It wasn’t until 1912 that Cadillac introduced an electric starter for its model, despite owning cars for over two decades. Before this innovation, starting a vehicle involved manually cranking the engine to life using a protruding handle.

The novel technology gained popularity swiftly; by the 1920s, virtually every new car was equipped with one. Turning on a car by hand was difficult, and if you didn’t remove your arm fast enough, the crank would happily break it. Quite a painful experience!

Credits Hemmings.com

What is the starter motor, and how does it work?

In contemporary automobiles, the starter motor operates on the same principle as it did in the past. 

The starter motor is a relatively small but very powerful electric motor that converts the battery’s electrical energy into mechanical energy. 

A starter motor is a motor specifically designed to initiate the rotational motion of your vehicle’s engine. It accomplishes this by engaging the engine’s flywheel, turning the crankshaft and beginning combustion. As the engine ignites and starts running, the starter motor disengages, allowing the engine to function independently.

When you turn the key, the solenoid switch directs an electrical current to the motor, enabling it to spin. 

The starter gear pops out, momentarily engages a ring gear on the flywheel, and rotates it. This movement turns the crankshaft, which moves the pistons and starts the combustion process. After the car is started, the starter motor disconnects from the flywheel, and the engine continues running. The starter motor consumes a lot of current from the battery, so once the engine runs, the alternator generates electricity and recharges the battery.

The modest but powerful starter motor, which works through the flywheel, has a considerable responsibility, and when it wears out, various problems begin to occur.

Have you ever experienced the frustration of turning the key in your car’s ignition only to be met with silence or a sluggish start? If so, you’re not alone. A malfunctioning car starter motor can put a damper on your day and leave you stranded.

Credits The Engineering Mindset

First thing first – check the battery!

As we have already mentioned in our videos or articles, you should always pay attention to unusual noises you hear coming from your car because they are a sign that something is not working as it should. They can be a sign of something very simple or something that, ignored, can lead to significant damage and very expensive repairs! Then, parts of the car can endanger you and others on the road if not replaced or repaired in time.

But now, back to the starter motor. It rarely breaks suddenly, but it can also happen. It usually gives some signs, which are clear warnings that you will soon be stranded. These warnings will help you solve the problem before you get stuck alone in the middle of nowhere with a car that won’t start. First thing first, if the car doesn’t start, before blaming for this the starter motor or any other part of the car, ensure that your vehicle’s battery is in optimal condition. Weak or dead batteries can often mimic starter motor issues. You can check the battery very quickly by putting the key in the ON position and trying to open the electric windows. You have a weak or flat battery if they are very slow or won’t open; the same with the lights. The battery can be checked with a multimeter, too. If the multimeter indicates less than 11.8 V, the battery must be replaced.

Symptoms of a bad starter

1. No crank/no start or one-click noise. This is one of the most common symptoms of a bad starter motor. This is due to an internal electrical issue: the starter solenoid isn’t functioning, or the starter brushes are worn out. A quick tip to help you start the car is to ask someone to go underneath and tap the starter motor gently with a hammer, a piece of wood or a long screwdriver while someone else turns the key. Repeat this operation if you didn’t have a result the first time. If you are lucky and the car starts, go to the mechanic for repair. However, the problem may also be caused by a dead battery, a bad ignition switch or an engine mechanical problem.
2. Grinding noise. The grinding noise can be heard while starting the engine due to faulty and worn-out starter gears, the starter fails to retract soon enough once the engine starts running, or if the flywheel teeth are damaged and mesh with the starter gear. Do not ignore the grinding noise, which can lead to expensive repairs if the faulty starter also damages the flywheel.
3. Whirring sound(freewheeling). This occurs when the starter pinion gear freewheels during the engine cranking because the pinion gear is not engaging the flywheel, which will also cause the engine to fail to start.
4. Intermittent starting issues. A faulty starter relay or dirty or loose wiring can cause this problem.
5. The starter stays on after starting. The starting circuit should close after starting the engine and then either releasing the key or letting go of the start button. You will know because it will make a hell of a noise. It means that the relay is stuck in the on position and can cause severe damage to the entire starter system and transmission flywheel. Shut down the car immediately.
6. Slow cranking. If you notice a sluggish cranking sound when you turn the key, it could indicate that the starter motor isn’t generating enough rotational force to kickstart the engine. This might be due to worn-out brushes or a weakened motor.
7. Smoke or burning odour under the hood. If you spot or smell the smoke rising, your starter motor is overheating because you continue to try to start the car. The possible causes can be a blown fuse, an ignition switch issue or a short circuit.

Conclusion

 If you experience these symptoms, it is best to go to a workshop as soon as possible to check the starter motor and the entire starting system. 

Advanced diagnostic tools can pinpoint the root cause of the problem, saving you time and effort. Remember that the starter motor is subject to wear and tear, and when it ends its life, it must be replaced.

Opt for a high-quality replacement from a reputable manufacturer. A well-engineered starter motor will ensure reliable performance and longevity.

Your vehicle’s starter motor may seem like a humble component, but its role in the smooth running of the car is irreplaceable. Knowing how it works and paying attention to the warning signs of a faulty starter motor can enable you to continue travelling confidently.