I noticed that this table calls out the cross cound point for stoichiometric as a function of airflow. why would you need such a thing?

I would guess that if the engine were providing the o2 sensor with highly variant f/a ratios then the o2 sensor might have a lag going from one extreme to the other and compensation would be in order.

And I thought that all those threads bashing NB o2 sensors for only knowing 14.7 were saying that there is only one Mv rating the computer could use to find it. All other voltages were unrelatable to a specific f/a ratio.

Seems like one might be able to raise this number for lower airflows to raise the f/a ratio -- but then we get into the whole mess of where the sensor is accurate.

Anybody have ideas?

 

This should help. . .

http://www.diy-efi.org/gmecm/papers/747fuel.txt

 

Like said above thats a valid way to do it. Set teh (or a) bias added into the stoich O2 voltage to get it to idle the way you want and then change the MAF tables around where the car idles to try and get the BLMs in line. Although I dont think the MAF cars have such a thing, do they?

 

Indeed I do have a table that lists the stoichiometric Mv value as a function of airflow in the 6e.

 

Change it and see how it works out. Adding a touch more fuel at low flows will probably help improve the idle.

 

Or take some out and get rid of a horribly stinking gas rich idle that comes from a big cam and no cats. Worked for me at least.

 

Its different for every motor. The cam probably screws with the O2, anyway. With my stock motor the richer idle seemed to help smooth it a bit.