[DonC]

Cautiously optimistic that the very faint light at the end of the tunnel may not be an oncoming train.
I noticed that in open loop the 02 sensors were reading very rich even when the wide band was reporting near stoich. As soon as closed loop is enabled the 02 values play a huge role in how the system manages the fuel. With the high readings the system was forcing very lean conditions to try to bring the 02 readings down (just like it's supposed to do when installed in a normal engine).
Thanks to a lot of input from the very patient folks at EEC Tuning.Org I reset the 02 bias very high and increased the switch point for the 02 sensors and tried it again. Much better results. The 02's are still reading very high but the system is making a much more moderate approach to it's corrections and I was able to get a data log that showed the system running in the mid to upper 15's and mid to lower 14's for stoich. This I can work with.
With the more moderate system corrections it has all but eliminated the rich tip outs that were causing such severe dirveability problems it ran into on initially enabling closed loop.
As I said, cautiously optimistic at this point.
It has, naturally, been raining here for the last five days so I haven't been able to get the car out to work on further refinement and further progress is going to be slowed by this but I'll be getting out whenever there's a break.
DonC