Dave,
Did u have any problems with installation of the SAFC2? My R33 Series II went haywire with dyno results jumping all over and caused engine stalling. I was told that the AFM for series I and II are different hence the wiring may differ.
Did u follow the N4-C terminal drawing with HW-4 sensor type as recommended on the SAFC2 wiring diagram (which shows the same for series 1 and 2)?
What are your settings for the SAFC2?