10 Reasons Why Your Car Won’t Start

August 06, 2021
Man buckling his seatbelt in his car.

It’s one of the worst things that can happen to a driver. You turn the key in your car’s ignition, perhaps hear a few alarming noises, and then…nothing. Whether in the parking lot after dinner, in your driveway before work, or even at the rest stop after you’ve stopped for snacks, there’s never really a good time for your car to not start. It’s usually indicative that your car needs some kind of repairs, and even when it doesn’t, it creates a serious logistical challenge on your hands.

What do you do when your car won’t start? After calling roadside assistance and getting you and your car to a safe location (preferably an auto shop), you’ve got to figure out why it’s not starting. Here are ten possible reasons why your car won’t start.

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1. Bad or dead battery

The most common reason cars don’t start is a dead or faulty battery.1 Even though most cars run on gasoline, they all require electrical power to function. The starter that cranks your engine to start requires an electrical signal to fire.2 If something’s wrong with your battery, your car engine won’t turn over. There are other symptoms that may indicate a dead battery, but checking if your engine turns over at all is always a good first step.

The good thing about dead batteries is that you don’t need a professional to get your car going again. Jumping a car battery is something that anyone with a base level of know-how can accomplish. Battery jumps are temporary solutions though, and new batteries can be expensive, so it’s best to just take good care of your battery. For more on how to do that, check out these tips for avoiding a dead battery.

2. Bad alternator

A bad alternator goes hand-in-hand with a bad battery. The alternator recharges the battery and keeps the car’s electrical systems running after the car has started. If you’ve got a bad alternator, you don’t necessarily have a bad battery, but you certainly might not have a functioning one. Any bad alternator should be replaced, so be sure to look out for any signs of a bad alternator.

3. Starter motor

Dead batteries or alternators aren’t the only things that can stop your ignition from functioning. If something is wrong with the aforementioned starter motor that receives the electrical signal to crank the engine, your car may not respond to the turn of your key.

Common symptoms

One of the easiest ways to tell if your starter motor has a problem is to check if your lights come on when you turn your key in the ignition. Turning your key turns your battery on, so if you’ve turned your key all the way and the lights come on, but the engine doesn’t turn over, your starter motor could be the culprit. Any signs of electrical failure could also indicate the starter motor needs help. Repeatedly trying to use a starter motor that has been subject to a blown fuse could cause it to overheat and emit smoke.3

4. Bad ignition switch

The ignition switch is another step on the road that leads from turning your key to starting your engine. It plays a crucial role between your battery and starter motor, carrying power from the battery to the engine.

Common symptoms of a bad ignition switch

If you have a bad ignition switch, you won’t hear the starter motor working to start the engine. You also might experience some electrical issues since the ignition switch effectively activates your car’s main electrical systems. Flickering or dying dashboard lights are a prime example. You may also have difficulty turning your key in the first place.4

5. Spark plugs

If your car doesn’t start, it’s possible that its spark plugs are old or dirty. Spark plugs that have become defective in any way can lead to reduced gas mileage, lack of acceleration, engine troubles like misfires, and yes, even difficulty starting your car at all.5

6. Broken distributor cap

It’s not necessarily the spark plugs’ fault. The distributor cap routes power from the engine’s ignition coil to the spark plugs. Broken or malfunctioning distributor caps can cause your engine to misfire, activate the check engine light, cause strange noises, and, of course, prevent your car from starting.6 Make sure there is no moisture under the cap and replace it immediately if it’s broken.

7. Bad timing belt

Your timing belt is another component that is integral to a functioning engine. The timing belt rotates the engine’s cam and crankshaft in unison, causing the cylinders to fire at the appropriate times.

Common symptoms of a bad timing belt

If something is wrong with your timing belt, you may hear ticking noises from your engine, strange disparities in your engine’s revving, or your engine may not turn over. Replacing your timing belt is a piece of maintenance that needs to be performed on a semi-regular basis, so if you notice any issues that could be tied to it, don’t hesitate to call your mechanic.7

8. Jammed steering lock

Ever gotten into your car and found that you can’t even turn your key? If you’ve experienced this, it’s likely that your steering lock is jammed. Your steering lock activates when someone tries to move the wheel while the key is not inserted in the ignition as an anti-theft measure.8 However, it can occasionally serve as an anti-driver measure by accident.

If your steering lock jams, try to wiggle it left and right and then gently turn it in whichever direction allows some movement. Once the lock is unjammed, you can turn the key in the ignition normally.

9. Clogged fuel filter

If fuel can’t reach your engine, your car is going to have a difficult time burning it. As obvious as that sounds, you might not realize that the fuel filter is preventing your car from starting.

Common symptoms of a clogged fuel filter

You may notice an array of fuel-related troubles, ranging from sputtering to poor gas mileage, and, of course, difficulty starting. Your fuel filter should be replaced every 30,000 miles, so if yours is coming up on that milestone and your car doesn’t start, it’s worth checking and replacing.9

10. Empty fuel tank

No one wants to run out of gas, but if you do, the silver lining is that there isn’t anything wrong with your car. If your tank is empty, your best bet is to procure a gas can and give your car the couple of gallons it needs to start, and get to a gas station.

Knowing why your car won’t turn on is a good first step towards repairing it, but sticking to a car maintenance schedule can help prevent issues from arising in the first place. Learn how to prepare for your car not starting or breaking down.

1https://www.erieinsurance.com/blog/7-reasons-car-wont-start, Accessed August 2021.
2https://www.autobatteries.com/how-batteries-work/how-your-car-starts, Accessed August 2023.
3https://www.firestonecompleteautocare.com/blog/maintenance/signs-of-a-bad-starter/, Accessed August 2021.
4https://mountainviewautorepairs.com/5-signs-of-ignition-switch-problems/, Accessed August 2021.
5https://www.championautoparts.com/Parts-Matter/automotive-repair-and-maintenance/fouled-spark-plugs.html, Accessed August 2021.
6https://www.autoblog.com/2016/01/07/symptoms-of-a-bad-or-failing-distributor-rotor-and-cap/, Accessed August 2021.
7https://www.scrperformance.com/blog/auto-mechanics-loveland/symptoms-of-a-bad-or-failing-timing-belt/, Accessed August 2021.
8https://www.carrchevrolet.com/service/information/what-to-know-if-your-cars-steering-wheel-locks-up-beaverton-or.htm, Accessed August 2021
9https://www.thedrive.com/maintenance-repair/37397/clogged-fuel-filter, Accessed August 2021.

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