The starter motor is a very underrated part of the modern car, making starting a car an experience rather than a chore. In the early days of the automobile, all vehicles had a lever attached to the crank, which was turned by hand to start the car, sort of like a kick starter on a motorcycle. You might have seen these in black-and-white films.
Luckily, a system of gears is now connected to a motor that “cranks up” the engine with just a key turn. The motor uses the energy the battery provides and is connected to the alternator and machine through a circuit and series of wires.
A bad starter motor can cause a car to die if the starter makes the battery discharge faster than the alternator can charge it or if the starter relay burns and causes a fuse to go out. Also, some faults cause a car to die while driving that might be connected to the starter motor.
Let’s see what they might be and discuss them below.
3 Causes of A Bad Starter Causing A Car To Die When Driving
Bad Starter Motor (Mechanical)
A starter motor is made of many parts, both mechanical and electrical. Let’s discuss the mechanical components of the starter motor and how they affect the performance of the starter motor if they get worn out.
There is a set of gears and motors that turn by the electrical power provided by the starter. If they’re worn out, have contaminated contact points, or have debris buildup restricting the movement or flow of electricity, this may cause excess drainage of the battery and load on the alternator every time you try to start the car cause drainage of the battery.
If the motor stays engaged in the starting motion even after the car has started, this damages the flywheel and starter pinion. This may cause the vehicle to stall and eventually die.
Diagnosing
To check if there is a faulty starter motor part, check for a grinding sound like a self-starter engaged after the car has started. You can also attach a voltmeter and check if the readings stay below 12V even after the vehicle has started.
Repairs
A starter motor can be repaired if it hasn’t damaged the flywheel or starter pinion, but getting a proper inspection of all the parts is recommended once you go in for repairs. An assessment is essential because it is recommended to replace the starter motor instead of repairing it.
After all, if the starter fails somewhere far from a repair shop, it will be a significant inconvenience for you. Repairs will cost around $30-$70, and replacing them would cost $100-$200.
Bad Starter Motor (Electrical)
There are several components in a starter motor that have to work in a proper sequence. This ensures a consistent flow of electricity and consistent performance of the starter motor. A bad starter motor drain battery and puts a load on the alternator if there are several faulty electrical components.
The starter circuit has a starter relay that has a switch. There is a starter solenoid that controls the amount of voltage that needs to be sent to the relay and the starter pinion.
A fault in the switch or relay may cause the start to stay engaged even after the car has started up, causing battery drainage faster than the alternator can charge it. As a result, the car dies after running a few kilometers.
A bad solenoid can cause insufficient electricity to reach the motor and starter pinion or too much electricity. This can cause the starter to go bad and put a load on the alternator.
If the solenoid is grounder, the bad starter motor drains the battery and stalls the car, and the car dies after running for some time.
Diagnosis
Diagnosing a bad starter motor can be very easy. A bad starter drains the battery, so you can check for dimming lights or other electrical components of the car not performing well enough. Bad starter noise can be heard whenever you try to start the car.
The sound is like an electric wire connecting and disconnecting rapidly.
Sometimes bad starter sounds resemble two metal pieces rattling against each other. You can also check for irregular or irrhythmic self-sounds.
Repairs
Luckily the electrical components of a starter motor can be changed for cheap rather than replacing the whole starter motor. The parts cost around $30-$50.
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Bad Ignition Switch
An ignition switch has a whole assembly of wires and fuses that control and regulate different components of a car. Among all those components is the starter switch, and within the fuse box is a starter fuse.
A faulty ignition switch may cause the car to stall and die while driving. The ignition switch may not conduct electricity properly due to rusting or damage and may cause shorting, draining of the battery, or the ignition switch to become faulty or damaged.
Sometimes the shorting causes fluctuation in the overall electrical load and may blow a fuse. This cause a break in the circuit, and the car dies while driving.
Diagnosing
Bad ignition switch symptoms are easy to pick up. The bad ignition switch symptoms are usually restricted to the cabin and the ignition switch itself. You can check for the faulty switch by turning the ignition and checking if the starter motor turns at all.
And if it turns, does it turn freely or with some resistance? Another thing you can check is if the ignition switch is conducting electricity properly or not.
You can check this by inserting a testing screwdriver in the fuse of the ignition switch and turning cranking the engine.
You can also remove the spark plug cover and create an arc jump to check if there is electricity reaching the spark plug itself.
Repairs
Repairs are usually very cheap and can be done by the owner if they can locate the fuse box. The fuse would cost around $1-$5.
If there is a problem with the ignition switch, have it checked and repaired by a professional because there is a whole set of wires and contact points that must be dealt with carefully.
The ignition switch repair would cost around $50-$85, depending on the fault.
Many visitors also read this related article: 8 Signs of a Bad Starter – Help & Advice
Conclusion
Check if there are bad ignition switch symptoms, bad starter sounds, or bad starter symptoms because a bad starter drains the battery and even damages the engine flywheel and the starter pinion. Repairing is time intensive and costly.
If the starter causes the battery to empty faster than the alternator can recharge it, or if the starter relay fries and blows a fuse, a defective starter motor might cause a car to stop when driving.
Likewise, various problems that might be linked to the starting motor can also cause a car to die while moving.
If the battery isn’t charging correctly, a battery sign lights up on the car’s dash, so always look out for that.
Modern cars have an eco-idle feature that kills the car every time it comes to a stop, and sometimes an error in that system causes the car to die while driving, which is an entirely different problem.
Hybrid cars also have this feature, and an error in the hybrid system also causes the car to die while driving, but that is totally different from a bad starter motor causing a car to die.