Help needed with odd dyno results (2.5l time trial car)

[The Radium King]

what codes were you getting when it wouldnt run closed loop?
was this recent - did you reset the dme?
were you getting any trims - rkat, fra?
the dme switches between open and closed loop based on engine speed (rpm) engine temp, and throttle position - perhaps on of these sensors is wonky (hmmm, throttle position comes up again ...).