fuel trims positive at 4400 but runs rich?!
04-06-2005, 09:46 PM
#2
if that is the case, how do i go about changing the PE table for that? just look where i have solid green o2s that read in the 900's and get them where i need it? my car is right at about 930 mv but now im seeing 950-970 and the fuel trims adding fuel
04-07-2005, 08:25 AM
#6
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First off you want to figure out whether you are getting
trimmed positive -for cause- or because of bad feedback
from the O2s. Sleepy O2s look the same as lean O2s and
the PCM doesn't know the difference.
Where are your fuel trim cell RPM/MAP boundaries, presently?
trimmed positive -for cause- or because of bad feedback
from the O2s. Sleepy O2s look the same as lean O2s and
the PCM doesn't know the difference.
Where are your fuel trim cell RPM/MAP boundaries, presently?
04-07-2005, 09:28 AM
#7
the map are 32 57 77 or something liek that and the rpm is something like 2000 6100 and 6200. the o2 sensors are oscillating nice. but i have always wondered about the boundaries for the rpm seeing the second and 3rd are really close together. its the stock setting i havent changed it yet, should i? and woudl that effect the airflow mode tables at all? i wonder if i shoudl copy a stock file or something from an 01-02 becuase i think their boundaries are more spread out. just let me know thanks for the help guys
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04-07-2005, 10:28 PM
#11
i put the cells at 1100,2800,4000. 2800 is where i started to up my timing so thats where i got that and then the 4000 is the limit set for the trims. 1100 might be put to 1000 about the highest the car ever idles.
sound good? will this change the VE a lot?
sound good? will this change the VE a lot?
04-08-2005, 07:47 AM
#12
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Those are more sensible settings. They don't change VE
per se. However you are now slicing the closed loop
operating area more finely and can see better where
the LTFT large values come from. A side bonus is, the
WOT trims come from the last cell you were in before
WOT, so the more you can segregate problem areas
the less you will see the + trims.
I use 1000, 2000 and 4000 but the details aren't that
important, just that you get all the cells in play. My
idle is 700.
You should see the trims rearrange over the next few
days. After that I'd say to check out where your lean
areas really are, and then disable closed loop (by the
ECT enable temp) and do some driving, logging the O2s.
Excel sort the data by RPM and MAP, find values that
are close-in to the VE table cell indices and see the O2
voltage; work the table by adding 0.02 for O2s < 100mV,
0.01 for O2s 100-350mV, -0.01 for 600-750mV and -0.02
for O2s over 750mV (but only where you see the fuel-air
multiplier is 1.000). Update, smooth in the cells that didn't
get data (by hand is probably better because you don't
want the smoothing function to drag around the new data,
you want the old data to move), drive & log again. This series
will converge you to a lower-end VE table that is pretty
dead-on for mixture, given enough iterations. In the end I'd
go and add about 0.02 to everything as a bit of pad, so the
LTFTs will be biased slightly negative.
per se. However you are now slicing the closed loop
operating area more finely and can see better where
the LTFT large values come from. A side bonus is, the
WOT trims come from the last cell you were in before
WOT, so the more you can segregate problem areas
the less you will see the + trims.
I use 1000, 2000 and 4000 but the details aren't that
important, just that you get all the cells in play. My
idle is 700.
You should see the trims rearrange over the next few
days. After that I'd say to check out where your lean
areas really are, and then disable closed loop (by the
ECT enable temp) and do some driving, logging the O2s.
Excel sort the data by RPM and MAP, find values that
are close-in to the VE table cell indices and see the O2
voltage; work the table by adding 0.02 for O2s < 100mV,
0.01 for O2s 100-350mV, -0.01 for 600-750mV and -0.02
for O2s over 750mV (but only where you see the fuel-air
multiplier is 1.000). Update, smooth in the cells that didn't
get data (by hand is probably better because you don't
want the smoothing function to drag around the new data,
you want the old data to move), drive & log again. This series
will converge you to a lower-end VE table that is pretty
dead-on for mixture, given enough iterations. In the end I'd
go and add about 0.02 to everything as a bit of pad, so the
LTFTs will be biased slightly negative.