Once upon a time, all cars were built solely for transportation. With a simple set of parts, cars were designed to move passengers from point A to point B, with little thought for anything else. 

As the decades moved forward, a lot changed with car production. Automakers added comfort, safety, and efficiency. 

Looking back at the history of the internal combustion engine, the carburetor played a big part in supplying fuel to the engine. Over time, designers added a variety of systems to keep up with modern day operating requirements. Carburetors had several different circuits designed to manage fuel for different reasons:

Main circuit – provide enough fuel for driving

Idle circuit – provide enough fuel for idling

Power circuit – provide enough fuel for acceleration 

Over time, as governments demanded stricter emissions requirements, catalytic converters were added to control the air to fuel ratio. Oxygen sensors were added to monitor the amount of oxygen in the exhaust. 

Technology changed, and the first fuel injection system was introduced as a way to improve efficiencies over carburetors. Common types include throttle body injection, multiport injection, direct injection, sequential injection, and central fuel injection. These systems have an injector at each cylinder, located in such a way as to be able to spray directly at the intake valve. It’s a faster, more accurate way of fuel metering, providing quicker response. 

How a fuel injector works

When a car works as designed, there’s little for a driver to think about. Step on the gas pedal, and the car moves forward. 

A throttle valve opens up as you press on the gas pedal, allowing air into the engine. As this occurs, the engine control unit (ECU) reacts and increases the fuel rate as air enters the engine. This occurs simultaneously. With any hesitation, you’d feel it in the way your car performs. Sensors ensure that the air to fuel ratio remains constant, and the amount of oxygen in the exhaust meets manufacturer’s guidelines. 

The fuel injector is an electronically controlled valve that supplies pressurized fuel into the system. As it’s energized, the fuel injector sprays pressurized fuel through a tiny nozzle designed to make the spray a fine mist so that it burns easily. The amount of fuel supplied is determined by how long the fuel injector stays open. This is controlled by the ECU. 

The fuel injectors are mounted to the intake manifold, so the spray directly connects with the intake valves. In order to ensure the right amount of fuel is sprayed, the ECU operates with a variety of sensors. They can include:

• Coolant temperature sensor – this monitors the operating temperature of the engine
  
• Engine speed sensor – this monitors engine speed
  
• Mass airflow sensor – this monitors the amount of air flowing into the engine
  
• Oxygen sensor – this monitors the amount of oxygen in the exhaust for the ECU to determine how rich or lean the fuel mixture is and make adjustments accordingly. 
  
• Throttle position sensor – this monitors the throttle valve position to determine how much air is being released into the engine
  
• Voltage sensor – this monitors the system voltage so the ECU can raise the idle speed if voltage drops
  

Fuel injectors will usually only fail in one of several ways

The fuel injectors on your vehicle are designed to last between 50,000 and 100,000 miles. This is impacted by the type of gas you put into your car, as well as how often the various fuel filters are changed. 

When fuel injectors wear down, it’s because:

The fuel injectors are clogged or dirty – when you turn off the engine, heat dissipates. This causes any fuel left in the injector to evaporate, which leaves behind tiny hard deposits. Over time, these can block the injector. 

The fuel injectors are leaking – fuel injectors can leak internally or externally. The most common reason is failure of the o-ring, which connects the fuel injector to the fuel rail. It can become hard and brittle over time from the heat of the engine. 

The fuel injectors fail – there are many moving parts inside a fuel injector. Over time, they can simply wear down and fail. 

Signs your fuel injectors may be failing

Your vehicle has more than 10,000 parts to ensure it operates effectively. Over time, any number of those parts can start to wear down. Few break or fail without warning. 

Like other systems on your vehicle, fuel injectors will start showing signs when there’s a problem. You may notice:

• It’s difficult to start the engine when it’s hot
• Your car has a rough idle
• You failed your latest emissions test
• You notice poor performance as you start your car and drive
• The engine has a difficult time reaching full RPMs
• You notice a decrease in gas mileage
• You notice smoke pouring from the tailpipe
• The car bucks at different throttle loads
• Engine knocking

Preventing fuel injector problems

Fuel injectors are hard working pieces that can last the life of your vehicle. Like any other engine part, regular maintenance is the key to keep it operating efficiently. If you plan on owning your vehicle for years, there are a few things you can do to keep it operating at its best. 

Regular maintenance and inspection

Vehicles don’t take a lot of maintenance. Most drivers do what’s necessary to keep their vehicles operating at their best 

It starts with paying attention to what you put into your vehicle. Go with a high grade gasoline. Get regular oil changes. And stick with a car care center you can trust; one who will get to know your vehicle and ensure it’s working its best. Fuel injectors should be inspected every 25,000 to 40,000 miles under normal circumstances, more often if you do a lot of short journeys around town. 

Keep your engine healthy by changing out the oil and fuel filter regularly. This ensures the engine has proper fuel flow. 

You can also pay attention to the way you drive your vehicle. Short start/stop journeys increase wear and tear. While you can’t change your driving habits if you work and run errands close to home, you can be aware of ensuring your car is well cared for. Give your engine a chance to cool off before you shut it off on occasion. Maintenance is key to keeping it operating well. 

And if you have any questions about how your car operates, bringing your vehicle in quickly will be your best bet every time.