The Evolution Of Fuel Injection

If you’ve ever ridden in an older car or owned a motorcycle, you know electronic fuel injection is far from the only design for an internal combustion engine. In fact, carburetors ruled the world of automotive design for a long time before EFI, and still owned a large share of the market for quite a while after it was introduced. There are a lot of reasons for that, and to understand them, you need to understand the difference between modern EFI systems and carburetors.

What Is Electronic Fuel Injection?

If you are new to automotive maintenance, you might know your car has fuel injection but not understand what that means. It’s a pretty common state to be in, and the principle behind the mechanism is simple. Where carburetors mix fuel and air using mechanical means only, fuel injection uses electronic monitoring and calibration to precisely control the air/fuel mixture. There are a few different designs, including an old system that was more like an automated carburetor.

The First Fuel Injected Car

While fuel injection systems were developed early in the history of the internal combustion engine, they did not enter the automotive market until the late 1950s. In World War I, fuel injected plane designs were used in the fighting, and it continued to make appearances in aircraft design after that. If you are asking yourself when was fuel injection invented, that is the answer, but what about the first fuel injected car?

GM introduced its first fuel-injection model to the automotive market as an option in 1957. It was in the options packages for many vehicles that year, but the early design didn’t have all the bugs worked out, so it was dropped from all models except the Corvette the very next year. It remained an option in the Corvette until 1965, leading many to remember it as the first successful fuel injected model.

The Fuel Injection Revolution of the 1980s

It took a couple of decades for fuel injection to take over the automotive world. First, revisions to that initial buggy design needed to be made. Then, a new marketing campaign aimed at assuring customers that the modern fuel injected engine was a different animal from the initial design in the late 1950s had to overcome the public perception of the option. Luckily, the numbers spoke for themselves as fuel injection models were tested side by side with their counterparts.

Today it might seem like intuitive truth that precision control over the fuel/air mixture so it precisely matches the needs of your head size and piston length will deliver better overall power and fuel efficiency, but when it was new it was just another possible point of mechanical failure in the minds of many mechanics and auto enthusiasts alike. The biggest contributor to the success of the systems in the 1980s was the increased computing power and smaller size of EFI modules, allowing for better control in the fuel injection system and a more consistent performance when it was used in engine design.

What Killed the Carburetor?

OK, so fuel injection is more efficient and precise, but that usually isn’t enough to totally kill a competing design, especially not when it is as easy to self-repair as most carburetors. What killed carburetors was air pollution. Carb designs, no matter how careful, simply produced more waste in the form of emissions than fuel injection did. As the Los Angeles skyline and other famous and highly populated areas felt the impact of widespread automobile use, local and state governments began stepping in to pressure the automakers, both behind closed doors and through emissions regulation. Eventually, the federal government followed suit.

Automakers spent much of the 1970s trying to design carburetor technology that would be able to keep up with the clean air demands being placed on vehicles, but in the end the designs became complex and unwieldy. It was simpler and more efficient to switch to electronic fuel injection, from both a design and a performance standpoint.

Single Port vs. Multi-Port Injection

Early EFI units typically didn’t last past 100,000 miles before burning out and needing replacement. For many, this set the upward life expectancy of a vehicle around that number once EFI became the standard. The main reason for it was a design feature called single port fuel injection. Single port injection looked almost like a carburetor with an air filter on top, but there were fuel injectors inside its enclosure, operating to precisely inject liquid fuel into a shared cavity for mixing with air. Multi-port injection split up the injectors and positioned the spray right before the intake valve to maximize efficiency, allowing for longer lasting and more efficient designs.

Direct Injection and the Modern EFI System

Single-port fuel injection initially suffered a power fall-off when compared to similar carb models because automakers had been so invested in carburetor technology for so long, they couldn’t design EFI systems that were optimized for the unique features of EFI at first. As they learned and shifted tactics to make use of the new technology, both power and efficiency came up until systems were performing better than the alternative while producing fewer emissions.

Direct injection was one of the steppingstones to modern systems that helped the process along. Introduced in the 1990s as vehicles became more compact and engines leaner and smaller for their power outputs, it represented a leap forward in the use of the tech. Direct injection’s big innovation was adding the fuel directly into the combustion chamber, rather than mixing fuel and air in the intake manifold. This allowed for even greater precision, and when combined with more reliable and powerful EFI controllers, it allowed the designs you see when you shop performance fuel injection upgrades today. Check out your options and find out how you can make the most of your vehicle’s power and fuel consumption curve.

Advice, how-to guides, and car care information featured on AutoZone.com and AutoZone Advice & How-To’s are presented as helpful resources for general maintenance and automotive repairs from a general perspective only and should be used at your own risk. Information is accurate and true to the best of AutoZone’s knowledge, however, there may be omissions, errors or mistakes.

Be sure to consult your owner’s manual, a repair guide, an AutoZoner at a store near you, or a licensed, professional mechanic for vehicle-specific repair information. Refer to the service manual for specific diagnostic, repair and tool information for your particular vehicle. Always chock your wheels prior to lifting a vehicle. Always disconnect the negative battery cable before servicing an electrical application on the vehicle to protect its electrical circuits in the event that a wire is accidentally pierced or grounded. Use caution when working with automotive batteries. Sulfuric acid is caustic and can burn clothing and skin or cause blindness. Always wear gloves and safety glasses and other personal protection equipment, and work in a well-ventilated area. Should electrolyte get on your body or clothing, neutralize it immediately with a solution of baking soda and water. Do not wear ties or loose clothing when working on your vehicle.

FREE Loan-A-Tool® program requires returnable deposit. Please note that the tool that you receive after placing an online order may be in a used but operable condition due to the nature of the Loan-A-Tool® program.