Electronic Fuel Injection Tech

All things related to the knowledge and understanding of efi and how it works.

What about it? Did you have a question?

Want to learn? Try here,


Google it. I’m sure there’s plenty of info on Wikipedia too.

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Simplest form. Computer controls the pulse widths of the fuel injectors based on air/fuel needs due to inputs based on engine load, coolant temp, barometric pressure, O2 sensors, etc, etc, etc and more etcs.

No I didn’t have a question.I was wanting to start a topic discussion about the subject just for the purpose of informing inexperienced or non mechanically inclined individuals about how different forms of efi works,its components and symptoms that can occur when said parts go bad,

Then why didn’t you post that in the first place? You haven’t been here all that long but you’ll find out pretty quickly that cryptic posts like the one to start the discussion won’t get very far.

The basics needed for fuel injection are a manifold pressure sensor, throttle position sensor, coolant temp sensor, and rpm sensor. From that, a you can run an open-loop, speed - density, batch fire fuel injection system.

All this is run by a ECU with maps calibrated for the specific engine. Typically the 3-D calibration map contains manifold pressure, rpm and the commanded fuel pulse width. That gives the base open loop tune. Pulse width is adjusted greater if the engine is cold and less if hot. The throttle position can give a boost to the pulse width if you are accelerating or cut off fuel at throttle closed.

That’s a minimum system. Modern cars all have much, much more.

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