Can you re-define the "airflow modes" in HPT?
09-12-2010, 02:15 PM
#1
Can you re-define the "airflow modes" in HPT? I am trying to get my NB's and STFT's to agree with the WB, so I am scanning the o2mv with the HPT scanner, I set up a Hist. using the plot value sensor as the o2 mV and table sensor as the mas Air flow in g/sec, and set 0-16 for the table and I noticed that the scan data all fell in modes 8-16, with almost everything above an idle falling in to mode 16, if this is the way GM set this up, no wonder us with LT's have a hard time getting CL to work...I want to re-define these modes so that light throttle is in one mode and med-heavy (non-WOT) is in another mode so I can adjust each, so I set the "mode vs air flow mode" to 0-8 for all areas of the table, the HP scanner and Hist. I set up still scans/plots as before plotting the data in modes 8-16 and I have no numbers higher than a 8 in the entire "mode vs airflow mode" table...Will this not work or have I set something wrong?
09-13-2010, 03:25 PM
#2
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There is an airflow mode vs airflow table that I have seen, but not messed
with. That is what determines what airflow_mode "bin" you occupy.
I recommend that you also rearrange the LTFT boundaries so all the cells
are in play, and crowded toward the low end where things are more prone
to vary w/ RPM.
with. That is what determines what airflow_mode "bin" you occupy.
I recommend that you also rearrange the LTFT boundaries so all the cells
are in play, and crowded toward the low end where things are more prone
to vary w/ RPM.
09-13-2010, 03:30 PM
#3
There is an airflow mode vs airflow table that I have seen, but not messed
with. That is what determines what airflow_mode "bin" you occupy.
I recommend that you also rearrange the LTFT boundaries so all the cells
are in play, and crowded toward the low end where things are more prone
to vary w/ RPM.
with. That is what determines what airflow_mode "bin" you occupy.
I recommend that you also rearrange the LTFT boundaries so all the cells
are in play, and crowded toward the low end where things are more prone
to vary w/ RPM.
09-14-2010, 05:51 PM
#4
I'm thinking what you want to do is adjust the o2 switching voltage in a certain airflow mode so that your WB & NB match.
I have used the switching voltage adjustment so that my low speed, light load area's run richer than 14.68 blah blah. If I remember I had that area close to 14.1 or 14.2, that really helped low speed surge/buck.
No reason I can see that you cannot make those same adjustments to the switching voltages so your WB & NB are what you want.
Keeping in mind that window is small.
I've had my LTFT turned off for a long time.
I have used the switching voltage adjustment so that my low speed, light load area's run richer than 14.68 blah blah. If I remember I had that area close to 14.1 or 14.2, that really helped low speed surge/buck.
No reason I can see that you cannot make those same adjustments to the switching voltages so your WB & NB are what you want.
Keeping in mind that window is small.
I've had my LTFT turned off for a long time.
09-14-2010, 07:44 PM
#5
My LTFT's are off also as my maf is spot on and the ve close, I experimented at idle from 800 rpm to 1200 rpm with setting all o2 switchpoints at 501 and scan, then 401, scan then 301 and scan, my stft's did not change!, the only thing that appeared to change was the switching voltage, it seemed to follow the switchpoint voltage I set...I don't understand, it was in CL, trims working, etc. and no change, the NB's are stock GM and only have about 2000 mi. on them, no codes...must be missing something.
09-15-2010, 07:39 AM
#6
Your STFT won't change but your AFR will, I went quite aggressive initially so I could the swing in the AFR. The switch voltage, I hope I say this correctly is what the computer sees to be correct. So depending what your stock switching voltage you may not see the AFR change as it is so small. So your trims work to that number, if your trims are good before they will be good after....they won't change.
I also found to help see the change as it is difficult because of the oscillation, set up the histo so you see the WB AFR in the columns.
The chart in one of the windows I set up the commanded AFR & my WB only & reduced the scale so use more of the window. Then I could see the WB oscillating above or below the commanded line.
If I remember correctly I run slightly richer in the g/sec airflow modes while slightly leaner in the upper cruise condition airflow modes.
I started to watch my fuel mileage at one point, I really don't care about mileage. It was fun to see some better numbers come up on the instant fuel mileage display.
I also found to help see the change as it is difficult because of the oscillation, set up the histo so you see the WB AFR in the columns.
The chart in one of the windows I set up the commanded AFR & my WB only & reduced the scale so use more of the window. Then I could see the WB oscillating above or below the commanded line.
If I remember correctly I run slightly richer in the g/sec airflow modes while slightly leaner in the upper cruise condition airflow modes.
I started to watch my fuel mileage at one point, I really don't care about mileage. It was fun to see some better numbers come up on the instant fuel mileage display.