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ancestors: drum brakes have been replaced by disc brakes, solid-axle rear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?

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