Can we reset "adaptation, mixture"?
 

Trying to figure out my Service Engine soon P1191 (Oxygen sensor too rich before cat. bank 2). Car runs fine. replaced tank breather valve (was getting an additional error on that originally) Cleaned up MAF, idle control valve, DISA seal is good, gas cap is tight. DMTL motor is working, cant find any air or vacuum leaks. Ruled out injector leaks as I switched them from bank 1 to bank 2 and still rich error ONLY in bank 2. Inspected and cleaned spark plugs.

Checked the adaptation mixture values and see they are different between bank 1 and bank 2. Do they constantly adjust or can we reset them?
Is it ever the case that we clear the "service eng. soon" too quickly and it returns because the car has not adjusted to the new or cleaned parts?

Thanks

Idle mixture values represent what the DME needs to do to try and get the mixture right as reported by the oxygen sensor. While on most cars they are somewhat adaptive to where they last left off but they should correct fairly quickly if the problem is repaired. If you are pretty sure that you have ruled out a vacuum leak I would maybe check fuel pressure. Just because the code only comes up on one bank doesn't necessarily mean the problem isn't common to both. Maybe someone else can verify if the idle mixture numbers are ever very close to being the same on both banks even when everything is operating properly? Or is there always some differences in the CCCV flow and other factors that make them different?

Also if Oxygen sensor is reporting "Oxygen rich" it means that you are "fuel lean"

Thank you.
I am not sure I have ruled out a vacuum leak - only that all hoses that I can see and think are vacuum lines look OK to me. Recent CCV replacement, cold climate.
within the the afternoon, I reset the error. Swapped the spark plugs and coils from 1-2-3 to 4-5-6 and error returned once again P1191 bank 2.
My mind I was thinking its too much fuel, always associated "rich" with fuel but DUHH...its the "oxygen" sensor reporting.....

Is there any tests for vacuum leaks?

My error sometimes stays off for several days/trips and they sometimes returns quickly (2 short trips) usually just as car is at warmed up temp (between cold/hot on the gauge). It may be returning quicker when the gas tank is full.

I am very much an amateur and stumble through and sometimes rely on my own misguided logic rather than knowledge. I am scared thats its a major valve/cylinder issue because it keeps coming up only in bank 2.

Any possible chance it could be as simple as an air filter? Just looked up when I replaced it about 30,000 miles its an off brand (looks fine).

THANKS!

If you don't feel you have ruled out vacuum leak then I would go back to that. Check as much as you can again, intake boot, hoses on back of manifold, brake booster lines, DISA o-ring(I'm assuming you replace it?) purge hose(front of manifold) etc. You could try a smoke test, I've never done one but looks like it works pretty good.

thanks for staying with me....
intake boot, completely went over - all good
hoses on back of manifold, intake or exhaust? (any rubber hose that I could see I ran my hand across)
brake booster lines,Did not check this - will tomorrow
DISA o-ring(I'm assuming you replace it?) Replaced some time ago, had to give it a good pull to get it off, not flattened and felt confident it was tight
purge hose(front of manifold) humm...replacing the purge valve I did give a good tug to the hose that goes under and towards the exhaust manifiold - cant see where it ends, could I have pulled this off????

OK, no problem ;) I wish someone else would chime in about my question concerning the idle adaptation numbers... anybody ???

Perhaps you need a reflash of the DME. BMW issued a TSB on this code or at least the BMW equivalent to this P code.

chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/http://www.bmwmotorsports.org/pdf/misc/120704.pdf

upallnight, that sounds very interesting! can't get link to work though ;(

the link is:
http://www.bmwmotorsports.org/pdf/misc/120704.pdf

THANK YOU, but I am not in the year range affected