okay....so we have an OBDI car (actually...it doesn't really matter...this is a technology post...not about specific cars)...

Lets say we're using two GM, heated O2s on a car that is programmed to enter closed-loop normally.

Until the motor reaches the pre-determined temp for closed-loop operation, the O2s might as well be dumb (speechless). They give data, but it's ignored. In this instance....MAF, temp, and MAP data help coordinate what does what. Am I on track here...?

Now...lets say the motor is now up to temperature and in closed-loop mode. The O2 voltages are being read and used to determine BLM values. BLM values assist in determining the amount of fuel added to the system at all load/throttle levels (this has been my perhaps misguided understanding for quite a while).

Now....we generally agree that O2 values are not used during WOT, however....BLMs are. Does this make the condition and accuracy of the O2 sensors directly related to BLM values which are then used to determine fueling during, O2-absent WOT...?

I am trying to figure out the affects of degraded performing O2 sensors on WOT performance of the car.

Please let me know if I need to submit myself for further counseling (on this topic) or if I am on track. I really want a way to determine what is really taking place here.

thanks much.

 

I think you should view it like this;

The o2's are an input sensor that influence the PCM to use a certain BLM cell.

The BLM or in obd-I block learn & then also intergrater, are the PCM's software programming each cell both BL & INT. will intiate a certain feul trim/pulse width.

They are there(BLM) no matter what, closed loop w/o2 's & in open loop , cold & WOT.

The O2's are used for fine fuel adjustments & are not used by PCM when inaccurate (cold) or unreliable/un-needed(WOT).