EFIE: Electronic Fuel Injection Enhancer, Described

As you can see from the title, EFIE stands for Electronic Fuel Injection Enhancer. It was developed for fuel injected vehicles, and was found to be necessary in order for other fuel efficiency devices to work on them. This includes virtually all cars and trucks today.

Photos of EFIE Devices

Another thing that is fundamental about an EFIE, is that it is not a fuel efficiency device on it's own. If all you did was add an EFIE to your car, with no other fuel efficiency system, you might gain a few mpg, but you also might not. The reason is that you are fooling the car's computer and making it run out of spec, or differently than it was designed for. The EFIE was designed to make the car run according to spec after another fuel efficiency device has been installed.

The purpose of the EFIE is not to provide fuel efficiency. It's purpose is to make it possible for other fuel efficiency devices to work. Basically a fuel efficiency device makes the engine think something is wrong, and makes it do things to adjust for this "wrongness". The actions it takes based on the oxygen sensor data, makes it negate the efficiency increase that would have been realized by the efficiency device. The EFIE solves this by adjusting the signal to the computer so the computer is happy with the readings it's getting and it's making the correct adjustments for the various conditions of the engine. A more detailed description of how the EFIE does this can be found here. But basically, the oxygen sensor tells the computer it's oxygen readings by providing a voltage between 0 and 1 volt. In order to adjust this "data" the EFIE adds a small voltage to that delivered by the oxygen sensor. The EFIE is highly adjustable. Adjustments to the trim screw can change the EFIE's voltage correction by tiny amounts; a millivolt or 2 (.001 volt).

In practice, with a good fuel efficiency system installed, you might want to have the EFIE adjust the signal from about 250 - 350 millivolts. For complete installation instructions, see EFIE Installation Instructions.

If you would like to purchase a pre-built EFIE, you can find it here, as well as a Dual EFIE unit, designed to handle 2 oxygen sensors. Both of these units have been designed to be economical, easy to install, and easy to adjust to your particular car and fuel saver combination. And they come with full money back guarantees.