NefMoto

I have never seen this topic covered, when we are running modified exhausts with no catalyst why leave the engine constantly switching from +/- 14.7 for the heater function to feed air then fuel over and over? Wouldn't we get better consumption since that extra fuel under 14.7 is pointless as we dont need to keep anything hot?

My car (me7.1) runs much smoother at idle and part throttle with o2s unplugged, killing trims and also the switching. Do others commonly do this and I am just behind the curve?

I would like to keep the sensors plugged in for trims and CL but not have it switch, I found these maps:

0x14efa - LAMSOSUF = 0.998779
0x14ef8 - LAMSOSOF = 1.001221   (you can edit them to 1.000888 as the closest to a true 1.00)

In the motronic me7.1 M-Box, I am going to try putting them both to 1, based off my reading I believe they are the upper and lower targets for the switch which in turn over shoots them both each time and forms a sine wave like afr pattern. Unless someone tells me not to I am thinking I can have both at 1 and it will not fluctuate???

Thanks in advance for any info that can be shared.

I just disable Catalyst heating all together.

How do we do that, the sai euro switch?

I noticed this in Banish's book:
"For this reason, many OEM vehicles sold today approach L = 0.82 (12.0:1 air/fuel) or richer once catalyst protection threshold has been reached. Unlocking control of this protection can be the key to properly calibrating such vehicles." Greg Banish, Engine Management, Advanced Tuning, p. 53.

And if we did disable this protection (which is probably there to make the CC last throughout the emissions warranty) what happens, does the CC just burn through, or does it get clogged - what does enrichment protection seek to do?

How?  I read the FR for hours over the weekend and looked at different maps, compared to different files and I never found something I was comfortable with tweaking other than these.  I read a a lot about and chased sub routines arounf for lamko, lamkhe, B_kh, cwlamkh and many others.

What do you do to just switch it off as that is obviously my goal?  Thanks.

B_kh = 0 once the threshold FKHABMN is reached.

Have you tried setting FKHABMN to zero?

oo. thanks. need to add that to the wiki.

i cannot locate those scalars/maps in m-box, h-box.  I have FKHABMN on F-box and can probably look at hex to find it in m.

B_kh and FKHABMN where two I looked into because from my reading it seemed they would be related if not responsible for the heating being on or off

I'll look for it time permitting. Maybe drop setzi a pm too...

FKHABMN - threshold terminating factor catalyst heating
0x1937D
Conversion - X*0.003906

exactly

Ok, had a chance to mess with it today, simply setting FKHABMN to 0.00 does indeed kill it.  I used the map settings above from phil and they worked perfect.

The idle is rock solid now and there is less fuel smell than is usually associated with running cat-less.  I am going to add this to the wiki because IMHO everyone not running cats should do this, there is no downsides that i can possibly see and the car is technically running better and more efficient.

settings

Sweet, thanks for the location/XDF info. I'll see if this reduces my gas stank.

Thanks!

Just got my car back together and added this to my tune.  THIS WORKS GREAT!  Idle is now rock solid.  No more switching back and forth.  This should be kept to the top. 

are you just deleting the dtc for this ? i am trying to do the same thing for my aeb m5.92 i believe the location for my lamda is somewhere in dhls  does anyone have any information about where i could start on the m5.92 ecu?

omg this...  did this work for you?  i am changing this immediately upon returning home...

thx for sharing Snow Trooper!

Such a small thing, but yet so epic at the same time.

hey - I tried this out and its made my idle less stable especially while cold.
snowtrooper, what were the other things you suggested turning off for regular twin-turbo apb/bel engines in conjunction with this?   obviously (or not?) we wouldn't turn off interchange diagnosis with this, or would we?  please advise...

I did this a few weeks ago, and honestly I didn't notice any difference at the time.  My file revisions since then rev to 2k RPM at cold startup, but I haven't had time yet to track down what changes might have caused that (not sure if it was this or not). Just thought I'd input.

This is likely your changes in KFMIRL/KFMIOP...  at least that's what I took from a recent thread on here about torque.  Something about changing timing tables when altering KFMIRL.  I didn't have any idle issues before changing my KFMIRL from stock to berttos's table.  It became worse with cat heating turned off.  However I think its optimal to have it off, so I need to figure out where the causal tuning issue is located... <unknown>

Any link to that discussion? I bet that is it (as I first noticed it after I made the major KFMIRL/IOP changes), and I have my plan of how I'm going to track it down, I just haven't had time yet.  I'm likely to start doing a lot more refining over the next few weeks though.  What I found interesting though, is that it's just the cold startup sequence that was affected (Revs to 2k for x-secoonds, then down to like 1200 or something for a few more seconds, then down to normal), and the rest of my idle is as rock solid as it ever was. I don't think it's going to be too hard to figure out what to tweak when I have a minute to put in some work.

I did this and it didn't seem to change anything.. I still get O2 oscillation @ idle as if it is active.

I don't get it, this is the 2nd thing I've tried on my ECU that doesn't work (the first thing being the KVB calculation factor)

No idea, my idle afr and even then as a result my idle speed use to swing around, now they don't.

I never ran it with the original idea of editing the actual Target values for the heating cycles.

Just a heads up.  I originally did this as described above, in conjunction with a change of KFMIRL/KFMIOP/KFZWOP/KFZWOP2 + misc. axis values relating to torque tables.  I experienced a nasty idle.  I then switched back these other tables to stock M-box and still left cat heating off.  This time, the desired result was achieved.  The car no long reeks of gasoline and the idle seems perfectly fine.  Definitely do this to anyone that hasn't where conditions apply to your particular setup...

All of my maps you describe are edited too, not with any calculators though.  Those things don't work.

Actually I don't edit kfzwop/2 just the axis data.

I have been told not to edit those.

optimally these would be taylored to your turbo setup via a variable-efficiency simulation.
it just depends on where MBT occurs - right?  isn't this directly related to the "alpha" of your ignition curves?
the interpolated changes from the s4 to rs4 are quite drastic;  we are getting mildly OT, but yeah - i've definitely seen big-name tunes which have altered axis values, altered table values, and both in combination.

the kfmirl/kfmiop mystery hasn't been solved on the other thread.  rick apparently knows...

hi
from wiki
Catalyst Heating
FKHABMN (0x1937D) - set to 0 if you do not have cats.

i need to change FKHABMN only if i have second lambda after cat?

I'm curious to try this, but does anyone know where it is on the 032HN file?

Tried the same address, and searching through the SW002 with no luck.

Helps? :)