Open loop

[fmster]

Hi to all!!! What is open loop and close loop? Need a reconformation on that.

 

[TurboDave]

Open loop means the ECM is doing it's fuel control based strictly on internal tables, while waiting for the O2 and coolant to get up to temp, then it will shift into closed loop.

In closed loop the ECM can then rely on feedback from the O2 sensor to maintain good air fuel ratio.

 

[fmster]

Open loop means the ECM is doing it's fuel control based strictly on internal tables, while waiting for the O2 and coolant to get up to temp, then it will shift into closed loop.

In closed loop the ECM can then rely on feedback from the O2 sensor to maintain good air fuel ratio.

SO the TT chip works on open loop,with no o2 reading?

 

[TurboDave]

Ummm, don't know for sure which versions do what. I believe they are at least open loop idle.

I'm no expert on TT chips, I run Extenders and Commanders.

 

[mikestertwo]

SO the TT chip works on open loop,with no o2 reading?

The TT chip runs in open loop at idle. It doesn't use the O2 readings to control fuel but uses the tables in the program. When you are off idle and cruizing at lighter loads the program goes into closed loop and uses the O2 reading to control fuel.