Injection Perfection By Karl Brauer
The last 30 years have produced a complete turnover in vehicle technology. Today's automotive components have little in common with their primitive ancestors: drum brakes have been replaced by disc brakes, solid-axle rear suspensions have given way to independent designs, and ignition systems are now electronic rather than mechanical. Yet of all these advances, none are as compelling as the shift from carburetion to fuel injection.
Certainly the use of fuel injection has been around for more than thirty years, but only since the mid-1980s has it became a widespread feature on almost every vehicle sold in America. Driven by a need for cleaner emissions, American car manufacturers were forced to give up the less-expensive carburetor for the more-sophisticated computer-controlled electronic fuel injection, or EFI. As a bonus, they also got better performance and improved fuel economy.
So what is it about EFI that makes it so much better than the simpler, less-expensive and easier-to-work-on carburetor? In a word: precision. Through the use of sensors, injectors and computer control, EFI provides a far more precise air and fuel mixture under a much broader range of operating conditions.
Why EFI is Better
It's obvious that EFI makes for a great technical discussion, but is it that much better than a carburetor? You bet. Remember that while driving your car your engine is in a constant state of change. In addition to the accelerating, braking, coasting or idling that comes with stop-and-go traffic, there's plenty of variation going on when rolling down the interstate with the cruise control set. You may be going up a mountain or descending into a valley. Maybe you're on a flat plane, but the sun has just set and the temperature is dropping.
The point is that only EFI, with its computer-based control module, can effectively keep up with the many changes our vehicles experience on a typical drive. Carburetors are mechanical devices that depend on springs, rods and engine vacuum to modulate fuel delivery. They can't accommodate for variations between individual cylinders, inconsistent octane, or altitude changes. More experienced readers will remember the days when moving between Denver and Los Angeles required a trip to an automotive shop for "rejetting" to keep a car from running too rich or too lean. Today, with the power of fuel injection, engine tuning is a no-brainer when traveling from the Rockies to the beaches. And isn't that the kind of driving experience we want?