CATEGORIES FOR ARTICLE LINKS BELOW

Big Red down double arrow

 

DOT Help

What is a fuel Injector?

By: Don Bowman

How do fuel injectors work?

Fuel Injectors

Fuel injectors are small electro-mechanical devices that are used to spray fuel into the intake manifold directly in front of the intake valve. The injector has a final high micron filter in the top inlet side and small hypodermic-sized holes on the bottom for the atomizing of fuel. The fuel acts as a lubricating agent for the injector. Water in the fuel is extremely damaging to the injectors due to the fact that it displaces the lubricating properties of the fuel.

Injectors open and close at the same rpm as the engine. This equates to more than 138,000 times an hour. Fuel injectors are subject to carbon and dirt introduced by a bad air cleaner element. The type of fuel used and the grade as well as the additives directly effect the life expectancy of the injectors. The computer controls the fuel injectors. They have power continuously when the key is turned on. In essence, the computer grounds the injector, completing the circuit and causing the injector to open. When the ground is removed, the injector closes. The computer, after receiving information from the various sensors, determines the length of time the injectors need to be grounded to inject the correct amount of fuel given the demand.

Fuel Injector Cut Away

The average fuel injector duty-cycle is measured in terms of milliseconds. The average is 1.5 to 6 milliseconds. Fuel injectors come in different sizes depending on the cubic inches and power demands of the engine. There are two basic types of fuel injectors. The first is the oldest version, which is the throttle body injection. This essentially is a system where one or two fuel injectors are located in the throttle body itself. They supply all the cylinders with a metered amount of fuel misted into the intake manifold. This charges the intake and the intake valve draws the fuel into the cylinder. This system was the most widely used system. More efficient than a carburetor, since it could adjust to air density and altitude and was not reliant on manifold vacuum, it was not as efficient as direct individual port-type fuel injection. The reason for this is that the cylinders closest to the injectors had a better mixture than the ones farthest away. Individual port type injection has eliminated this flaw by injecting the same amount of fuel to each cylinder. (click for enlarged photo)

Fuel Injector Cut Away GM

Some of our favorite injectors are the following:

***Remember*** to check for other relevant information in the columns and article tables.



ATTENTION READER:

If you enjoyed the information and article you just read be sure to check out our newly released book with even more exciting photo's and information:
How to Turbocharge and Tune your Engine
How to turbocharge and tune your engine Book
Follow Enginebasics on...
Youtube Engine Basics Car building tuning modifying motors

Want to know more about your particular Make and Model vehicle? All of these vehicles are covered in the tech, maintenance and repair articles found above. Enginebasics is the wiki or wikipedia of car part, repair, how to and tuning information. Let us be the class 101 for your automotive learning.

Ford General Motors GM Pontiac Jaguar Land Rover Nissan
Toyota Honda Lexus Acura Lotus Scion
Infinity BMW Mercedes Mitsubishi Ferrari Maserati
Lamborghini Volks Wagen VW Saab Audi Hyundai Kia
Subaru Mazda Chevy Volvo Caddilac Dodge
Chrylser Daewoo Porsche Mercury Freightliner MG

Individual Models

Ford Mustang Mitsubishi Eclipse Mitsubishi Evo Subaru WRX / STI Dodge Viper Chevrolet Corvette
Nissan Skyline Honda S2000 Nissan 350z Toyota Supra Chevy Camaro Lotus Elise Exige
Honda Civic VW Golf Dodge SRT-4 Eagle Talon Acura Integra BMW M3
Nissan 240sx Porsche 911 Acura NSX Honda Accord Toyota Camry Toyota MR2
VW R32 Dodge Truck Mazda Rx7 VW Jetta Sand Buggy Nissan Sentra
Try The Car Enthusists Test (Link) and see how much of a motorhead you REALLY are.

Latest Car Automotive News Engine Basics

For the latest Automotive news and stories visit the websites below



Our feature Build: An AWD V6 Civic