How do you log fuel trims with the rear o2 deleted?

 

The rear O2 has absolutly nothing to do with logging/adjusting trims, this is the job of the front O2. The rear is simply there to make sure the cat is working. About .12 seconds worth of searching would have told you the same thing.

 

And about .121 seconds of searching would have told you that certain ways of disabling the rear o2 also causes fuel trims to stop working. I can't remember which but there's ways to disable it without losing your trims. Or you can enable it, let the cel come in, dial in your injectors, then disable it again.

 

The rear o2 trims don't tell you anything useful. The real trims are based off the front o2.

 

I don't think there is such a thing as rear o2 "trims", but certain ways of disabling the rear o2 disables fuel trims, which do come from the front o2 sensor.

https://www.evolutionm.net/forums/ec...rim-issue.html

This is a thread that I started for the same issue. It's been discussed in several other threads also.