Another Rich Decel Thread..Need Help

[WeathermanShawn]

2002 Camaro Z-28 H/C as noted in signature. Stock 2002 injectors. Car is mechanically sound.

I have had difficulty accomplishing OLSD as my primary tuning option. Many hills and elevation changes in my area. I end up sampling multiple and widely varying g*K/kPa values at the same RPM. I have noticed the BARO value doesn't change accordingly while driving, and without holding pressure constant I am sampling data at RPM/MAP cells that becomes unreliable.

But my question is on the widely familiar Rich Decel problem many of us have. Whether I run CLSD, CLMAF, or 'regular' CLSDMAF (stock closed-loop), if I let off the throttle at any RPM, my AFR reads 12.9-13.2 for at least 9-10 seconds. Why does it do this?

I have lowered VE in the 15-20 MAP to almost zero g/kPa values, and it has no effect. I have even logged FTC cell 21 and it always indicates it is pulling 7-9% fuel, but my wideband reads rich. Is this just a reality with injectors, even stock? Is it just a reality of having a bigger cam?

The wideband is calibrated, I have no vacuum or exhaust leaks. Ultimately I realize I can just utilize DFCO and my problem is solved. But, it makes lower MAP tuning difficult, and I am just very curious why.

Anybody have any constructive opinions or comments to enlighten me?