Why Won't My Car Start?

Updated January 2019

Just about every vehicle owner dreads the moment when their car, truck or SUV won’t start. What should you do? Who should you call? Can you fix it yourself? Here’s a list with ten common reasons why cars don’t start up and what you can do about it, all backed up by an expert from the Universal Technical Institute.

“The first step is to define the no start” said Joe Spadafora, certified instructor at Universal Technical Institute’s Exton, Pennsylvania campus. Spadafora spent the majority of his career in working in the service department of several dealerships and receiving factory training from GM. He’s certified as a Master Technician and certified by Chrysler as a Dodge Viper technician. He also holds certifications from Subaru, Suzuki, Toyota, Lexus and Scion as well, so if there’s something wrong with your car, chances are he’s seen it before.

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To diagnose the reason your car isn’t starting, you need to pay attention to happening when you turn the key. “Does the engine crank but not actually start or, when you turn the key, does literally nothing happen?” he said. “In a customer’s eyes, the following two options are the same because both create a scenario that results in the vehicle’s failure to run.”

While the two situations might seem similar, they have very different meanings that are important to a mechanic and can signal different problems calling for a variety of solutions.

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“A major factor that affects batteries is called parasitic draw or drain,” Spadafora said. “This occurs when your vehicle is shut off but some of the computers are using small amounts of power to maintain learned or stored information.”

Parasitic drain happens naturally and the battery can be recharged via the alternator with some daily driving. But if the car hasn’t been used regularly, the battery can wear down and not have enough juice to start. Excessive parasitic drain can come from things like leaving your headlights on when the vehicle is off. Make sure you turn all of your vehicle’s accessories off before you walk in to your house or your destination, as this is probably the most easily avoidable way to get stranded.

“Most consumers are familiar with the corrosion that accumulates on the top of a battery by the terminals,” says Spadafora. You might have seen this on older cars that have been used frequently – it sort of looks like sea foam has accumulated around the ‘+’ and ‘-‘ battery terminals. This can affect the connection at the battery terminals. This can be easily cleaned off using water and baking soda, which neutralizes the battery acid.

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Spadafora warns that even clean batteries can lose charge over time, so ensure that you keep your car battery up to date.

Spadafora also mentioned that if you try to start the vehicle and the lights don’t dim or flicker when turning the key, then you most likely have either an ignition switch, park/neutral switch, relay starter or wiring issue on the control side of the starter circuit. Cars need to be in park or the clutch needs to be depressed to start. If the switch isn’t in the right position then the car just won’t start.

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Many car keys today are coded or programmed to work with their car, like a fingerprint that’s unique to both the key and the ignition. However like with any electronics, the programming can get buggy. That confuses the security system and stop you from starting your car.

“With today’s modern security systems, it’s important to check that you have the proper key coded to the vehicle,” said Spadafora. “Even vehicles with smart keys (ones where the key fob can stay in your pocket and you push a start button) can cause issues.” Interference can be an issue, and you should double check the battery in the fob.

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Maybe this seems too obvious, but an engine needs a spark, fuel and compression to turn over. If the gas tank is dry, then the engine may crank, but not get the car started. While this is likely the least expensive issue on this list, it can foreshadow bigger problems down the road. Running your car to empty isn’t good for the fuel pump or fuel filter.

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This could be related to the above section: gas kind of acts like a coolant for the fuel pump in the car, so if you run at a low, the pump will suck in some air, which will create heat, causing the fuel pump to wear prematurely. Sometimes a fuel pump will just burn out on its as well.

A fuel pressure gauge will show whether or not the engine is getting the right amount of fuel. Fuel delivery issues are commonly the reason why your vehicle will turn over but not start, so if you’re having problems, ensure that your fuel injectors, fuel pump and other components are working properly.

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Spadafora also mentioned that solenoids aren’t the only thing that can go wrong with a starter. The gears, bushings and bearings can all go bad out and when they do, it can lead to a non-start situation. It’s fairly easy to tell if this is the problem: if your headlights are bright when the car is off, but dim when you try to turn the car on then you may need to get a new or rebuilt starter. Some starter motors will last the entirety of your vehicle’s lifespan, whereas others may burn out more often. It’s hard to say how long your will last.

“With the advent of all of the computer-controlled systems in our vehicles today, common basic maintenance protocols can often be overlooked,” said Spadafora. “It sounds obvious, but keep in mind that an engine won’t start without fuel, spark, compression and timing.”

Basically, without a spark your car won’t start. Your spark plugs, or ignition coil may need replacing before your engine can turn over. Additionally, sparks need to happen at the right time and with enough voltage to start the car. A bad spark plug lets itself known with poor engine performance before it reaches a no-start situation. If you can recall the car running a bit roughly, or being hard to start before the car refused to turn over, then you may be dealing with a spark plug issue or ignition timing issue.

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A no start situation could occur if your fuel system is clogged. That means no fuel is reaching the engine, similar to how a lack of gas would stop your car from starting. A clogged fuel system can occur when dirt or debris get into the fuel lines, something that can happen with a bad fuel filter. The filter in modern cars is found inside the fuel tank and typically doesn’t need to be replaced until well past the 100,000 mile mark. Dirty fuel injectors can also lead to a no-start.

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