I know AFR error in closed loop is a bad idea as things like DFCO and trims will skew the readings....
But just wondering.... would it be possible to setup a histogram to record the fuel trims under Closed Loop normal driving conditions?
Essentially the trims are very similar to the AFR error we use to tune with.... they are basically "on the fly VE tuners"
So couldnt we log those and use them to tweak our VE tables as well?
(i am just thinking out loud... trying to make use of normal driving time to better our cars... i know i spend alot of time driving... and wish i could spend less time tuning... so hoping to find a way to make the best use out of what i am already doing)
Yep, there was another thread on this a while back. It can be done, but using wideband would be ideal.
Not sure why you car targets such low AFRs with the O2 sensor information disconnected. Mine targets 12-13s when in VE logging mode.
2001 Olds Alero (LD9)
636 whp / 543 ft-lb
@turboalero
Shifted wrote:And just how do you plan on "tweaking" the trims?
No no no... not tweak the trims... use the trims to give us info on how the VE table is... and tweak the VE tables. I know you cant adjust trims.
[ion wrote: C2]Yep, there was another thread on this a while back. It can be done, but using wideband would be ideal.
Not sure why you car targets such low AFRs with the O2 sensor information disconnected. Mine targets 12-13s when in VE logging mode.
I know wideband is better... but i was just trying to think of a way to do "ongoing" tuning to follow main WB tuning like as we drive around if we noticed our logs showing the trims were excessive... we could nudge the VEs a bit.
just thinking out loud... i guess i am getting sick of driving around in logging mode... just hoped there was a way to log without logging mode...
I tred this. If you're using fuel trims (only active in closed loop), you won't be able to tune the VE table cells where the car is in PE. Think about it - fuel trims are inactive during open loop/PE, so you're not going to get any meaningful data while you're in PE, which, IMO, is where you want the MOST meaningful data.
Using a wideband and the "AFR %Error" method takes maybe three iterations at the most before your actual AFR is almost dead on with your commanded AFR in open loop. At this point, as long as your injecor constant is correct, you should be finished. If you go and make changes to the spark timing, you may want to go back and do one more iteration on the VE tables...
oldskool wrote:I tred this. If you're using fuel trims (only active in closed loop), you won't be able to tune the VE table cells where the car is in PE. Think about it - fuel trims are inactive during open loop/PE, so you're not going to get any meaningful data while you're in PE, which, IMO, is where you want the MOST meaningful data.
Using a wideband and the "AFR %Error" method takes maybe three iterations at the most before your actual AFR is almost dead on with your commanded AFR in open loop. At this point, as long as your injecor constant is correct, you should be finished. If you go and make changes to the spark timing, you may want to go back and do one more iteration on the VE tables...
Yeah, i guess.... but i am mostly concearned with the non-pe driving... My WOT doesnt seem to have much problem...
so that is where i thought the trims would help out. As i mentioned, i do my tuning with a WB... and have my WB on at all times, and typically am logging anytime i am driving by myself. Just to keep an eye on things and have a record in case something funny happens. but the afr error histograms are useless in closed loop. so was looking for other options.
I don't understand. You have been told before that we can not tune closed loop. Computer does it and shots for 14:7:1
FU Tuning
ah ya gotta love the internet... so easy to mis-read something.... and so hard to explain things....
I dont want to control closed loop operations.... I am fine with closed loop as it is...
I was just wondering if there was a way to gather information on how to better tune our VE's by making use of information that could be recorded durring normal day to day driving (which more often than not is in closed loop)
I assume we all drive our cars more than we "tune them" So just looking for ways to make use of the time we are just tooling around to better assist us in making them run better. some sort of histogram with filters or something to ignore bad data... or by monitoring trims and things that react to in-accurate VE tables.
I just like to have HPT running anytime i drive by myself... it is interesting to see how everything works as you drive. And in case things act up... like stalls, or sputters, or anything out of the ordinary, you can glance over and see what might have burped to cause it.... So just thought "hmmm maybe there is a way to make use of these "ongoing" logs to help in tuning VE's or timing."
That is all. nothing major.
ken soggs wrote:I know AFR error in closed loop is a bad idea as things like DFCO and trims will skew the readings....
But just wondering.... would it be possible to setup a histogram to record the fuel trims under Closed Loop normal driving conditions?
Essentially the trims are very similar to the AFR error we use to tune with.... they are basically "on the fly VE tuners"
So couldnt we log those and use them to tweak our VE tables as well?
(i am just thinking out loud... trying to make use of normal driving time to better our cars... i know i spend alot of time driving... and wish i could spend less time tuning... so hoping to find a way to make the best use out of what i am already doing)
NEVERMIND I AM AN IDIOT....
I was using the wrong injector constant and using PASTE>MULTIPLY and thus no matter how hard i tried, i could never get it tuned to my liking... so was always looking for ways to turn whatever i was doing into a "tuning/logging run"
Well once i got the proper info, and did it all the right way, i had my car dialed in perfectly within 2 hours. and now i dont have to even think about VE anymore... So yeah... disregard my idiotness.... this thread is now meaningless.
