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oztracktuning
May 18th, 2006, 11:54 PM
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
May 19th, 2006, 12:17 AM
Sorry, can't run the AFR MAP vs RPM table and have long term trims.

Cheers,
Ross
oztracktuning
May 19th, 2006, 12:25 AM
OK so how can i get it to work without RPM vs MAP but using OS3?
GMPX
May 19th, 2006, 01:31 AM
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
May 19th, 2006, 01:42 AM
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
May 19th, 2006, 01:54 AM
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
July 4th, 2006, 01:29 PM
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
July 4th, 2006, 03:47 PM
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
July 4th, 2006, 11:14 PM
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
July 4th, 2006, 11:29 PM
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
GMPX
July 5th, 2006, 12:36 AM
B3647 is only operational in OpenLoop, can't really change that.

But, I am a little lost, why do you guys want LTFT's when in theory, you have gone to a MAFless custom O.S because you want to dial in your VE table spot on. I've been in open loop for a long time and I see no ill effects or drifting AFR's.

Cheers,
Ross
Delco
July 5th, 2006, 11:12 AM
B3647 is only operational in OpenLoop, can't really change that.

But, I am a little lost, why do you guys want LTFT's when in theory, you have gone to a MAFless custom O.S because you want to dial in your VE table spot on. I've been in open loop for a long time and I see no ill effects or drifting AFR's.

Cheers,
Ross

Ross if the VE isnt dialed in 100% ou will see a drift , a good tune wont drift , the LTFT's account for a poor tune
Highlander
July 5th, 2006, 11:25 AM
When you have a lot of weather changes... it gets a bit hard to make a good tune in little time...
Delco
July 5th, 2006, 01:08 PM
When you have a lot of weather changes... it gets a bit hard to make a good tune in little time...

Yes I went for a 2 hr drive yesterday , went away tuning and went from 8 deg to 24 deg and from a barometric pressure of 103 to 93 kpa due to the altitude and the tune was spot on. Given this was with a TPS map on the way up and a MAP tune on the way down ,this tune has been refined over about a week of logging and realtime tuning though , its all in the time , put the effort in and the results will come.
GMPX
July 5th, 2006, 02:06 PM
a good tune wont drift , the LTFT's account for a poor tune

I didn't want to be the one to break the news :)
Highlander
July 6th, 2006, 11:20 AM
Yes I went for a 2 hr drive yesterday , went away tuning and went from 8 deg to 24 deg and from a barometric pressure of 103 to 93 kpa due to the altitude and the tune was spot on. Given this was with a TPS map on the way up and a MAP tune on the way down ,this tune has been refined over about a week of logging and realtime tuning though , its all in the time , put the effort in and the results will come.
That i know... I just don't have that available time to do it. I have set a very good tune on my father's car and honestly it varies very little...

What do you call spot on? all 1.0 on ben?
To me spot on is still a bit forgiving... +-2%

The quality of fuel can honestly change a tune... a bad fuel with too much alcohol will change quite a bit your trims.

One other thing i wanted to add... NO matter how good i dial in my VE.. a change in humidity will simply make my BENs get all wacky.