ok so I'm trying to give this sd tuning a go but I'm seeing some weird stuff that is unexpected or unsettling.
I've attached my basic sd tune file, config file, and a sample log file.
in my tune file I set the maf fail=0, dfco temp=280, copied my high octane table to the low, and set the pe multiplier to 1.25 across (for later use).
I figured that these changes would be an ok starting point.
I started up and began the logging after clearing the trim tables.
I let the car idle and warm up for a while. I noticed the car went into closed loop. (I thought it wasn't supposed to do that for sd tuning??)
so i used the vcm controls to turn off closed loop.
then I went for a leisurely drive, captured close to 25mins of data, figured that was alright for a starting point as i try to figure out what the heck i'm doing.
while driving, the first thing i notice that bothers me is that the commanded afr is hovering down around 6.8-7.5!
well that just seems totally wrong to me.
shouldn't it be up around 14.7?
so I have no idea why it is commanding such a low number....
where does that commanded afr come from?, how is it derived?
I watched the w/b as the computer desperately tried to drag the afr down to those lowly numbers, it made its way down to the 10's often...rich huh?
after gathering the data i put a filter on the afr error% histogram, set a 10count for this initial sampling.
didn't cover too much square footage of the table, but ok for a start.
so this data is showing me that my afr error% is ranging from 55% to 103%!
huh?
can that be true?
that seems wrong to me. but yeah, that afrcmd is throwing things off i bet.
if you look at that histogram you can see those numbers
I tried special pasting % into the ve to see what it looked like.
looks totally wacked to me!
so i already figured i was doing something quite wrong here. definitely not understanding a few things.
next I looked at the ltft histogram.
used the same 10count filter.
ok, it didn't look as wacky.
most of the cells said -1 which ought to mean no change required.
a few of the low rpm cells logged -11,-14,-5,-4, etc.
so anyhow, I feel like I've missed out on some really important step here. I'm headin down the wrong path maybe.
any assistance would be greatly appreciated.
I've read and re-read the info available in these forums till I get to a point that I feel confident enough to give it a whirl. but then I run into some unexpected results.
oh, and another question....I was reading in some other threads that some don't bother with all this tedious ve tuning stuff, but rather take a simpler route and do maf tuning only. I think it might have been russk that was discussing this. so is that a viable option on the lsj?? and if so what is the approach to take to accomplish that on this engine?
Thanks!
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