View Single Post
Old 08-10-2017, 10:05 AM   #5
Senior Member
Tor's Avatar
Join Date: Feb 2015
Drives: Toyota GT86
Location: Europe
Posts: 919
Thanks: 369
Thanked 546 Times in 300 Posts
Mentioned: 40 Post(s)
Tagged: 2 Thread(s)
Originally Posted by steve99 View Post
A few guys on here have disavled rear 02 compensations due damaged 02 sensor , seems no noticable effects

Anyone with a rear 02 connected flex kit will also have those compensations disabled

You will also need to disable a couple of cel codes as well as the three compensation tables set to zero

Aparantly tjese conpensations only used during cruise fueling like on highway
Thanks Steve. Setting the "A/F #3 correction Limits" to 0 doesn't trigger any CELs, so I think it's safe to say that it's only necessary to do changes to other tables if removing the sensor completely.

"AF#3 learn" is also still active in my logs. I'm not sure what table that corresponds to in RomRaider, if any. These are small corrections between 0 and +0.34 and only during OL. I am wondering if it's "A/F #3 CL Target Compensation Limits", the description in RomRaider seems like gibberish to me, but the limits of that table are +0.5/-0.5.

Originally Posted by guybo View Post
Your fuel trims are fine. LTFT Within +/- 5 is ideal, within +/- 10 is acceptable, don't worry about STFT. Your total trim is great. But you need to tell us what your trims are at idle and at 2500 RPM
Thanks for your reply! All help is always appreciated, so I don't hope it comes across wrong when I say it seems either you missed the point or I didn't express myself clearly in the original post.

I am not worried about either my LTFT or STFT at all. What is bothering me is when my ECU one day set WOT LTFT of e.g. -1.2 and the next day e.g. +3.56. That causes a wildly unpredictable AFR that one day is too lean and the next day too rich. The point of this thread is to see if the swings are caused by the rear o2 sensor compensation being erratic for one reason or another (like header design, lack of cat or combination or a 4th unknown reason) and what the effect is when disabling those compensations.
Tor is offline   Reply With Quote