Long Term Trims

[oztracktuning]

How can i be certain i have Long Term Trims activated in an OS3 tune.
I want to be able to have lean cruise enable but be able to specify some AFRs using the AFRS vs RPM table. But also want some LT trims? Can it be done??

[GMPX]

Sorry, can't run the AFR MAP vs RPM table and have long term trims.

Cheers,
Ross

[oztracktuning]

OK so how can i get it to work without RPM vs MAP but using OS3?

[GMPX]

Change the closed loop enable temps to normal values.
Note, you then revert to P.E Mode as well for any fueling other than 14.63, B3647 is gone!.

Cheers,
Ross

[oztracktuning]

I think i already had it set like that.!
How long does it take to start storing LT trims - The car was driven only a short distance but it had all the trims as zero. Its short term trims were quite small though and its average ST trims in the log were around -1% ???

[ringram]

Why not just use STFT instead of LTFT. If you set AFR to 14.63 in OS3 it will use STFT at that level and when outside of this leaner or richer it will command what you want.

[oztracktuning]

If i have OS3 working with LTFT actually being stored. What is happening then in B3647? It still says rpm and map - so does this work like it has the old coolant temp axes

[Blacky]

If i have OS3 working with LTFT actually being stored. What is happening then in B3647? It still says rpm and map - so does this work like it has the old coolant temp axes

I believe it will still function as a modified RP/MAP table (not temperature). However, because the table is ONLY used in open loop mode, it won't be used 99% of the time because you have enabled closed loop by putting your closed loop enable temps back to "normal".

Ross correct me if I'm wrong.

Paul

[Highlander]

That is really what i wanted... to be able to have B3647 with closed loop AND having a more defined LTFT Storing? instead of 22 cells... having like 100 cells or something? something akin to a RPM vs MAP B3647 table?.. can it be done as another custom OS?

[Blacky]

That is really what i wanted... to be able to have B3647 with closed loop AND having a more defined LTFT Storing? instead of 22 cells... having like 100 cells or something? something akin to a RPM vs MAP B3647 table?.. can it be done as another custom OS?

No. Closed loop means the O2 sensors are used to trim fuel. Narrow band O2 sensors can only accurately "see" stoichiometric combustion. So you can't run closed loop at anything other than the AFR that is the centered on the O2 rich/lean switch point.

The LTFT cells structures are not easily changed. They are hard coded into the PCMs software.

Regards
Paul