4. Components of the Fuel System & How It Works

When you fill up your Subaru, that gas goes into the fuel tank. From here, the fuel pump draws the gasoline through the fuel lines up towards the engine. It passes through a fuel filter, just in case there is any particulate or other debris in the gas. Once it reaches the fuel rail, the fuel injectors spray a precise amount of fuel (mixed with air) into the combustion chamber, where the process of combustion takes place.

This is a very basic overview, of course, but these are the primary components of the system. Keep in mind that this is only true of modern engines. If you're rocking a classic car from before the late 1980s, you may well have an engine with a carburetor instead of fuel injectors.

3. What Goes Into Fuel System Maintenance

The good news is that fuel system maintenance is relatively simple. You'll want to have the fuel filter changed at the recommended interval--or earlier, if it happens to get clogged. Moreover, it's a good idea to have your fuel injectors cleaned as necessary. While there are certain additives that may be able to help, a professional cleaning service is the best way to make sure that your injectors remain clean, free of debris, and performing at their best.

2. The Importance of Using the Correct Kind of Fuel

Your fuel system is fine-tuned to accept a specific kind of fuel. Any deviation from this could lead to trouble. Some mistakes could lead to very minor problems; for example, if you put gasoline with a higher-than-necessary octane rating in your gas tank, the only downside will be that you paid extra for something you didn't need. However, the opposite is not true. While most Subaru models only require regular unleaded gas, the Subaru BRZ, Subaru WRX, and Subaru WRX STI require premium fuel. If you fill their tanks with lower-octane fuel, you could damage the engine.

Fortunately, accidentally using diesel is next to impossible, since the diesel nozzle at gas stations is designed in a way to keep it from fitting into gas-powered cars. However, if you put E85 gas into your Subaru, you may run into drastically decreased performance. The best way to deal with this is to top it off with regular gas little by little.

1. Symptoms of a Bad Fuel System

A damaged fuel system can be irritating and expensive, so it's a good idea to try to catch troubling signs early. If you turn the key or push the ignition button in your car and the engine cranks, but doesn't start, it could be a sign of a clogged fuel filter, clogged fuel injectors, or a faulty fuel pump. If your car starts, but the engine sputters, it's a possible sign of fuel system problems. Similarly, if the engine surges and hesitates instead of providing smooth, linear acceleration, the fuel system may need immediate attention. Keep an eye out for decreased gas mileage and performance, as well.