So when the ECU detects open loop on our cars what all is disabled? I know of EGR but what else? Will the AC compressor clutch deactivate as well? What else?
Umm. Yes/No. Open Loop vs. Closed loop. For ECU. Open loop refers to when the ECU no longer uses input from the o2 sensors to calculate fuel delivery. I.E. your Air/Fuel ratio will no longer be for fuel economy (you will run richer). There is another sensor (WOT (wide open throttle) that is detected, that disengages things like the AC clutch (if AC is enabled). It may just be a 'terms' difference. But if you tell a tuner you want to adjust "open loop" you may not get what your wanting. [eek]Open loop is once the computer detects that the engine has warmed up it starts using all the sensors (engine temp, oil pressure, coolant temp)to run the car rather then pre programmed algorithms