Open loop, stft

Hey guys first post here.

just got my hptuner and had my car running for the first time under vcm scanner and noticed my stft were averaging around -10 with cold motor. Now I’m aware that any data isn’t really valid when engines cold I was more curious as to why stft were doing anything when engine was cold (15c) as it was running in open loop.

Answer may be obvious but I’m new to this. I was under the impression that stft were a correction from incorrect Commanded lambda. But since my o2 sensors were yet to fully warm up where were the corrections coming from?

ltft were at 0

L77 engine e38 ecu. Completely stock besides an otr.

thanks!

o2 sensors warm up rather quickly especially with cats in place. there is an o2 readiness table that is a dead time vs. temp table that tells how long before o2 sensors should be used. if your generating stft's, you are, by definition, in closed loop.

thanks for the response!, appears its set to 10s and ect -40, explains why i was seeing STFT values. i had in my head that they wouldnt start working until engine was atleast closer to operating temp.