Reasons Your Car Will Not Start

Find out quickly why your car won't start in the information below! At Shingle Springs Subaru, we're here to help when you need expert service from a Subaru factory-trained team of experts. Below, we've outlined the most common reasons your car might not start properly, according to what factor is preventing the car from starting up. Some are fast and easy to fix, like installing a new battery. Others might require an in-depth diagnostic to isolate the source of the problem.

For the most part, every car needs the following things to start. If one of them is missing, the engine may be difficult or impossible to start up!

Carbon build-up has fouled these old spark plugs 

5. A Spark

When air and fuel are mixed in the engine's cylinders, the resulting mixture stores a lot of energy. A spark detonates it all at once, which creates an explosion that drives the pistons and ultimately makes your car run. That means your car needs to store electricity in the battery in order to run. If the battery is dead, there's no power for the engine's starter (more on that below) or the spark plugs, and the engine won't run. In that case, you may just need a jump start. As you drive, the car recharges its own battery, so just drive around for at least 15 minutes after getting a jump start to make sure there's enough power in the battery to get you going again next time. Or, if the battery is too old to hold a strong charge any longer, it'll need to be replaced.

This driver is about to find out whether the battery on her car is dead or not 

4. Fuel

If fuel isn't getting to the engine, the engine won't be able to start. It needs a pressurized stream of fuel provided to the engine's fuel injectors by the fuel pump. If the fuel injectors are dirty and clogged, or the fuel filter needs to be replaced, or the fuel pump itself has gone bad, there won't be enough fuel getting to the engine. If the battery is good, consider getting the fuel system checked.

3. Air

The air that mixes with the fuel in the engine doesn't just come from all around the engine. It's drawn in by a sealed intake system, which measures and controls the precise amount of air getting to the engine for a clean burn. If you have a bad oxygen sensor, mass airflow sensor or throttle body, the engine might not be getting the air it needs to run. There could even be a blockage, such as a badly clogged engine air filter choking the engine from its air supply.

A modern car is started with the aid of a starter motor like this one 

2. A Push

Remember those old-timey, 1920s cars that you had to get out and crank from the front to start? Well, today's engines aren't much different. They still need an initial push to get started -- it's just that modern cars come with their own starter. It's a small electric motor that spins the engine to get it, well, started. But if the battery is dead, there's no electricity for the starter. The starter itself can also fail if the electrical signal can't get from the ignition key to the starter.

1. Something Else!

Of course, modern cars are extremely complex, especially hybrid electric cars, and there can be some unexpected reasons why your vehicle won't start. Computer-controlled systems in today's vehicles govern pretty much every aspect of the car. A computer failure related to none of the above could potentially prevent the car from running. When things get tricky, we invite you to visit the certified Subaru experts in our service department.