What is Open/Closed Loop? I'll Explain How It Works. Must Watch!

Did you know that your vehicle goes through open loop closed loop many many times? You probably didn't know because 99% of the time you don't feel it and even know it happened. Its like switching a light switch.

Open loop is basically when you start the vehicle to let it warm up. The ECU/PCM is ignoring input from the lambda sensors aka oxygen or air/fuel mixture sensors. It doesn't care how much air fuel mixture is there as long as the engine is running.

Now when it enters closed loop then it cares what the sensors are saying. that way you can better optimize fuel for a clean combustion process.

Its very interesting how all this was thought up and put onto vehicles. And the fuel mapping and how everything happens in milliseconds thousands of times a min.