Fuel injection is a fuel-supply system that has taken the carburetor’s place, increasing vehicle reliability, efficiency and emissions performance.

Fuel injection serves the same purpose as a carburetor, supplying fuel to the engine at a ratio of 14.7 parts air to 1 part fuel — or at least attempting to. Fuel injection does so with greater precision, due in part to its ability to adapt to different temperatures and operating conditions. As air temperature changes, so does its density, which alters the air/fuel ratio. The result is a fuel mixture that is either too lean or too rich. Consequences include incomplete combustion, pollution, rough running and difficult cold-weather starting. Electronic fuel injection — that’s the “EFI” you see thrown around in vehicle literature — monitors airflow and density, among other conditions, and more precisely controls the fuel supply over a range of temperatures and engine states.

Fuel injection was popularized in the 1980s, and all new cars sold in the United States since 1995 have been equipped with EFI. Injection types differ from vehicle to vehicle and include throttle body, single-point, multi-point (port), sequential and direct fuel injection.

Information for this was taken from the Cars.com’s glossary, written by Joe Wiesenfelder.

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Answered by Joe Bruzek on January 29, 2009 in Glossary | Permalink

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