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13 Reasons Why Your Car Struggles to Start (and DIY Fixes)

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Car engine

Here you are in the middle of a parking lot with a trunk full of groceries. You’re turning your key to no avail. Why the heck is your car struggling to start? Well, there are 13 potential reasons.

In this piece, we’ll explain each of the 13 reasons why your car struggles to start. More importantly, we’ll give you some easy DIY fixes to start your car and get you home.

The Car-Starting Process

Let’s briefly discuss what happens under the hood when you start your car. The turning of your key sends a signal to a small starter engine. This requires power from your car’s battery.

The starter engine will start moving and it will engage a bigger gear. This gear ultimately leads to your engine turning over and starting to run. When the engine starts, fuel and air will start pumping around the system.

Spark plugs make a little spark (ever wondered how they got their name?) which ignites this mixture of fuel and air. Boom. Your car is now running.

13 Reasons Why Your Car Struggles to Start (and DIY Fixes)

As you can see, there are a lot of moving parts when it comes to starting your car. For that reason, it might be tough to pinpoint exactly why your car is struggling to start. Let’s get into why this is happening.

1. Dead or Dying Battery

One of the usual suspects is a dead or dying battery. The starter motor needs input from the battery to fire up. On top of that, there are a number of components that need battery power to operate.

If your battery doesn’t have enough juice, then your car simply won’t start or will struggle to do so.

For completely dead batteries, troubleshooting is easy. If your electric key fob doesn’t work, then that could be a sign that your battery is no good.

Solution: First, check the health of your battery. You might need a jump start or a complete replacement.

Car battery inside vehicle

2. Loose Cables

If anything is missing a proper connection, your car can struggle to start. Cables can become loose by driving through bumpy roads routinely or just naturally over time.

This is a big culprit if you notice issues right after doing some repairs to your battery, fuel pump, or starter. Failing to securely connect all the cables after a repair will cause this problem.

Solution: Double-check the cables and wires throughout your vehicle, especially after doing repairs yourself.

Close up of a mechanic inspecting the car wiring

3. Fuel Filter is Clogged

The fuel filter takes out particles from your gasoline as it flows through your car. These particles are dirt, dust, and rust that could damage your engine if they bypassed the filter.

Like any other type of filter, fuel filters clog over time. Once clogged, it dramatically restricts the flow of fuel through the line.

With enough restriction, your engine won’t see enough fuel for ignition to take place. You might have to turn and hold your key multiple times for the fuel to finally ignite.

Solution: Check the filter. If it’s clogged, replace it. The part costs less than $50 in most cases.

Car fuel filter
Car fuel filter

4. Starter is No Good

If your little starter motor is busted, then the first step of the starting process won’t work. Remember, this little guy does some upfront work that ultimately leads to your car’s engine starting.

If you turn the key and hear a clicking noise, that could be the starter telling you it’s dead or dying. If you jump the car and nothing changes, it’s another good clue. Finally, if lights and windows work but your car won’t start, you can blame the starter.

Solution: Replace the starter. You can do this yourself and the part costs about 100 bucks.

Car Starter 2
Car starter in the engine bay

5. Ignition Switch is Faulty

There’s a little electrical switch in your ignition. When you turn your key, a signal gets sent that you want to start the car. This signal is the first domino that knocks down the rest and begins the car-starting operation.

Overuse and highly humid areas can both cause your ignition switch to go bad. If your car randomly dies once the engine is started or your lights sporadically turn off, it could be due to this ignition switch.

Solution: Bad news. Replacing this is a really big undertaking. You’re better off going to a mechanic and having them fix it.

ignition switch with ignition key
Ignition switch

6. Oil is Too Thick or Dirty

If you didn’t know that the oil in your vehicle needs to be routinely changed, you’re in danger. Neglecting this piece of maintenance for too long will result in thick and dirty oil. This sludges the fluid down and slows down the whole process.

Oil needs to be a certain viscosity or else it won’t work. Too dirty, and the oil won’t allow the car-starting process to move forward.

Solution: Get a dang oil change and replace the filter! You can change it yourself for cheap.

Car mechanic draining the old engine oil

7. Not Enough Fuel

You’ll notice that part of the starting process involves a fuel-air mixture. Not enough fuel means the mixture won’t be rich enough to get ignited by the spark plugs.

If you’ve been putting off your trip to the gas station, this is the unfortunate outcome. Of course, you could also swap to an electric vehicle and never worry about this.

Solution: Grab a gas can, get a ride to your local gas station, and use that to fill up your vehicle.

Low fuel - gauge

8. Alternator is Broken

The only way to keep your car’s battery charged is with a functioning alternator. This charges your battery whenever the vehicle is turned on and running.

If your alternator isn’t working, then your battery will slowly run out of juice. If you have a squealing noise that gets louder when your radio is on, it could be your alternator screaming for help.

Solution: Replace the alternator for a few hundred dollars in parts.

Old worn out car alternator

9. Broken Fuel Pump

How does the fuel get pumped through the car’s system? With a fuel pump, of course. This little guy is responsible for circulating fuel from the tank to the components that need it.

While starting your car, you need that rich fuel-air mixture we keep talking about. If fuel isn’t making its way downstream to the engine, you can forget about your car ever starting.

There’s a way to see if your fuel pump is failing. Get in your car and turn the key to the “on” position (not fully turning the key. You don’t want the engine to turn on). Go out of your car and squat next to the gas cap. Listen carefully and see if you hear a pump quietly running.

This is better if you have a buddy that can turn the key while you listen. If you don’t hear anything, it might mean that the fuel pump isn’t running.

Solution: Replace the fuel pump for less than a hundred dollars. The replacement process doesn’t take very long and it’s not overly difficult for most vehicles.

Car fuel pump assembly
Fuel pump assembly

10. Fuel Line is Frozen

If you’re tuning in from the northern half of the world, you might see some really cold temperatures where you’re from. If they’re cold enough, your fuel lines can actually freeze.

This is a rare happening, but it’s very possible. If water makes its way into your fuel tank, you have a good chance of it turning into ice when it gets especially cold outside.

The ironic thing is that the best way to warm up a fuel line is by running your engine. A bit of a catch-22, huh?

Pro tip: always keep your tank at least half-full in cold weather so water can’t freeze your lines.

Solution: Use a little fuel additive to get rid of moisture and free up your lines. You might have to wait for the lines to thaw a little bit before it really works.

Car fuel lines running under the vehicle

11. Spark Plugs are Due for Replacement

Did you know that spark plugs need to be replaced every 100,000 miles? If you have an American car, that’s about the same mileage that you need to turn your car into the junkyard. We joke we joke.

In all seriousness, replacing your spark plugs is a necessity to start the vehicle. As we mentioned, these little plugs make a spark that ignites the all-important fuel-air mixture we keep addressing.

An old spark plug won’t be able to make the same spark that it used to. Like a retired NFL player. Plugs are really easy to take out and replace, so this isn’t a huge deal.

Solution: Replace the spark plugs. Take a look at the old ones and compare them to the new ones to see the mechanical difference.

Used spark plug car
Worn-out spark plug

12. Built-In Security Measures

Not a lot of people know this, but there are actually some built-in security measures on newer cars. For example, if you try to put the wrong key in a car and start it, there’s a system that might shut down the ignition switch for up to 20 minutes.

This obviously varies a ton from car to car, but it’s important to know that it could happen.

Solution: All you can really do is wait. Guess you have some time to read other articles on our site, huh?

Instrument cluster showing diagnostic lights with the security light on

13. Did You Forget Your Key Fob?

To our fellow forgetful drivers: did you forget your key fob? I can’t count how many times my keys were in my jacket which was in the living room as I was pushing the start/stop button desperately in the car.

If the car doesn’t sense that your key fob is nearby, it won’t start. You’ll know this is the case if you look at the dash and there’s a message about a key not being close enough or something. Alternatively, you can pat your left pocket and see if you feel your key.

Solution: Grab your dang key, laugh at yourself, and try again.

Wireless car key fob showing all the buttons


A car that struggles or refuses to start is old news. Now that you know what causes it and some simple DIY solutions, you can fix your car’s starting problem. For more troubleshooting guides, explore our blog. Stock up on the accessories and tools that make your car into an easy-to-drive automobile.

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Ernest Martynyuk

An automotive enthusiast who's been tinkering with vehicles since I was 15-years old. Repairing automotive electronics has been my main job for over a decade now and have a passion for everything technical regarding cars.

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