P code expert?? What's the trim "system"?
 

I can't get rid of my P1191 trim "system" error

How is this different from P1093 (I don't have this error, but have followed the same logic to resolve a "rich" condition.

My P1191 error goes on to tell me - pre cat o2 sensor too rich bank 2

The DME in an effort to try to maintain a proper fuel mixture will make adjustments(trim) the fuel to the rich or lean side to bring the air fuel ratio to where it wants it to be. Usually it uses a kind of look up table 8 bits wide which gives 256 cells to the table. Usually the target is in the center at 128 and the DME will go to higher or lower cells to try to correct (trim) the mixture. I think in DIS or IMPA you can actually watch this as it happens and it should give you the target number and show you how it's compensating. If the compensating goes beyond a normal range the DME assumes there is a problem and it will set a code.

The trim numbers are usually just cell numbers (labels) though not an actual measurement or quantity of anything.

If you want to verify what Upallnight said about the trim numbers and which way is rich or lean you could just play around a bit by causing a vacuum leak, maybe disconnect a coil, and watch what the trim does to compensate.

Looking at the Bentley I would say if P1093 is rich and P1091 is lean then maybe P1193 is rich and P1191 is lean but maybe one is at idle and one at cruise ?? Don't forget it might well be that the trim is rich to compensate for a lean condition so I would definetly play around a bit while you are watching the numbers to verify.

The first step the correcting the issue is to find out what model this is. I'll assume it is a 3.0i

The second thing is to note that o2 sensors do not usually fail and cause lean or rich mixtures. The software in the DME can detect if there is a lazy o2 sensor and set a fault for aging. Replacing the o2 sensor will only cause the mixture values to adapt faster to a malfunction. Do not replace any o2 sensors for this fault. You should really only replace o2 sensors if they have aged faults.

If you have access to BMW software, read the entire fault memory. On M54 engines, a faulty engine wiring harness can cause lean/rich mixture faults, but will show transmission failsafe/ dsc messages also.

Then make note of the mixture values, so afterwards you can determine if your repair was successful or not.

If you get values such as this, and have not had the car worked on recently or have not reset adaptations

Bank 1 Additive 0.00ms
Bank 2 Additive 0.00ms
Bank 1 Multiplicative 0.00%
Bank 2 Multiplicative 0.00%

There may be a very large air leak, or a faulty air mass sensor.

If you get something like the following

Bank 1 Additive +0.34ms
Bank 2 Additive +0.20ms
Bank 1 Multiplicative -1.00%
Bank 2 Multiplicative -2.50%

It is almost impossible to have a lean mixture at idle and have a rich mixture off idle(above 1300rpms)

This usually indicates a faulty air mass flow sensor, but you should smoke the intake system to check the throttle body boot.

If you get something like this

Bank 1 Additive 0.30ms
Bank 2 Additive 0.25ms
Bank 1 Multiplicative 2.50%
Bank 2 Multiplicative 6.50%

This is usually caused by a faulty valve cover. There is probably a crack between cylinders 4-6. This can be confirmed with a smoke test.

If you get something like this

Bank 1 Additive 0.30ms
Bank 2 Additive 0.25ms
Bank 1 Multiplicative 4.50%
Bank 2 Multiplicative 5.50%

This is usually caused by a leaking DISA or engine oil separator return hose. This can be confirmed with a smoke test.

If you have no other faults beside o2 sensor faults, and you smoke the intake system, and have no external air leaks, and you test the crankcase ventilation system for proper operation, then most likely the software in the engine computer is faulty and should be updated. There is a bulletin that describes this situation.

WOW Killcrap, great info - thanks!
Yes, 3.0i
All started with a check light telling me "tank Ventilation solenoid" bad AND a message that bank 2 post cat O2 was not heating properly. I replaced tank vent solenoid AND as milage maintenance replaced all O2 sensors. (makes sense I made them more sensitive).

"a faulty engine wiring harness can cause lean/rich mixture faults, but will show transmission failsafe/ dsc messages also" - I DO NOT GET THAT MESSAGE.

"or have not reset adaptations" - HOW DO YOU RESET THEM??

I cleaned my air mass sensor (many times)
I smoked my intake, no signs. Used harbor freight pump - pumped cigar smoke into intake then blew into the hose (with my mouth) to force pressure, but I don't think I pushed it beyond the intake (should I have opened the throttle - pressed the pedal??). The intake held smoke pressure (my finger on the tube after blowing into it) and I saw no smoke leaks.

Swapped injectors/spark plugs/coils from bank 1 to bank 2 - ERROR DID NOT MIGRATE, ALWAYS BANK 2

"faulty valve cover. There is probably a crack between cylinders 4-6. This can be confirmed with a smoke test" - HOW DO I SMOKE THIS? I replaced Valve cover gasket 40k miles ago- oil leak.

My DISA "O" ring is not original, seems tight and no smoke
cleaned up and verified the idler control valve (got it rotating very easy)
Did a compression test, all 6 cylinders very close in range of 200-205 PSI.
Replaced my CCV system 20K miles ago. "test the crankcase ventilation system for proper operation" - HOW DO YOU TEST IT?

I need to do my homework and check the additives valves, I had found them once, saw that bank 2 were different but have since forgot how to get back to those valves. I use BMW DIS on my laptop.

software in the engine computer is faulty and should be updated. There is a bulletin that describes this situation - MY CAR DOES NOT FALL INTO THE AFFECTED YEARS

THANK YOU VERY MUCH!

I think what you need now is a professional to physically look at your vehicle. If money is no object and you want to learn lets shop. If money is an object and you want to just replace parts, be my guest.

Purchase the following tools first

Smoke Machine: I recommend the OTC (6522) LeakTamer EVAP Smoke Diagnostic Machine

Air Compressor: I recommend a Rotary Screw Compressors for noise concerns.


Manometer: I recommend a manual version instead a digital one. Dwyer Roll-Up U Tube Manometers

Buy these first and get back to me.

Yikes! I forgot what the question was!

I feel like a got a "Shellacking" for showing my ignorance.....

Still very much appreciate the guidance.

Don't feel bad, that's the way Killcrap treats everybody.

I had the dealer "flash" the engine computer DME, he said it flashed very quick so he did not think anything was really updated or changed. (of course they did not let me watch). It probabley re-set the adaptation valves with a flash??

My "service engine soon" light returned, same P1191

my adaptation values:
Bank 1 Additive .06 ms
Bank 2 Additive .04ms
Bank 1 Multiplicative 4.8%
Bank 2 Multiplicative 7.9%

I might have a faulty valve cover gasket?

THANKS!

I think your problem is related to why your fuel system doesn't hold the pressure once the fuel pump stops running.

Did you have the hard start problem when you bought the X or did it start after a couple of months/years of ownership?

hard start only on warm engine first noticed last year after 11 years.

Can i verify that on the fuel filter:
"in" is the black line that comes from the electric fuel pump
"rtn" is the blue line that goes to the fuel tank on the drivers side

and then the other blue line goes on to feed the fuel rail

TAHNKS!

Sorry can't help you there because I don't remember what the colors were when I did mine.

I knew of a former X owner who installed his filter backward. When he started the engine and revved the engine the fuel pressure would go down instead of going up.

that didn't happen with me.... but perplexed why there is a 'return" at the filter and not at the fuel rail. In my case, when I loose pressure when the car/pump is off - that trapped air has to be then pushed out through the injectors??

So adaptation values are how much FUEL is added at idle and then
the multiplier during acceleration??

my multi in bank 2 almost at 8% exceeds the limit? Well then why doesn't the DME just beef up the additive and tone down the multi??

my adaptation values:
Bank 1 Additive .06 ms
Bank 2 Additive .04ms
Bank 1 Multiplicative 4.8%
Bank 2 Multiplicative 7.9%

The fuel regulator is built in with the fuel filter and not at the fuel rail as in previous design, that's why the return line is at the fuel filter and not the fuel rail.

Kevinkay , have you checked the vacuum line that goes to the regulator on the fuel filter. It could be leaking vacuum causing a vacuum leak and a rich mixture, or if the regulator diaphragm is leaking could cause extra fuel to be delivered through the vacuum line. As far as the pressure loss after shut off, if you could install an inline shut of valve (or even a check valve)before and/or after the filter you could try to narrow down exactly where the fuel is leaking back. Pinching off lines sometimes works but not so dependable. What software are you using to check your adaptation numbers ?

Uncalled for, I wouldn't have taken the high road. I use only basic diagnostic stuff and get along just fine and my bet is I am part of the majority. I do all my own work and would have to spend a week figuring out how to check all that stuff. You don't need to spend thousands of dollars on equipment to do some troubleshooting.

As an example, it doesn't always work but you can spray carb fluid or propane around hoses and intake and if it reaches a vacuum leak the idle will momentarily change. Key here is it is only one bank so it already narrowed down some.

Let's back up. Put the codes aside. What are the symptoms? Rough idle, poor acceleration, hard start etc. ? How long has it been going on? Has it been getting worse. Were the codes there before you did the work you mentioned?

Thanks

It all started:
I got a check eng. light which told me the purge valve solenoid was bad along with a message that the post cat O2 sensor in bank 2 was not heating as expected (not sure if this also set the light off or just an error message). I changed the purge valve and because I am close to 200k (changed the O2's at 100K), I went ahead and bought new bosh O2 sensors, changed all 4.
Then shortly after I got the Service soon light and the error code P1191 - too rich in bank 2.
It makes some senses that I might have been running rich in the past but the new 02 sensor is more sensitive.

The temp has been in the teens and there is ice holding down my cars hood - so I have avoided anymore troubleshooting.
But, I do have some "mayo" on the oil cap so I should look into the condition of the CCV assembly even though it was all replaced 1 year, 20k ago.
Also - Killcrap mentioned a "faulty valve cover" crack between 4 and 6. In my mind I was thinking the valve cover gasket - but that doesnt make sense as the gasket does not separate the cylinders - but the cover does??
Anybody tell me how to smoke test the valve cover?

THANKS!
Kevin

I think you would be able to see if the valve cover was cracked. The way the CCCV vacuum lines are set up it is possible that a vacuum leak can affect one bank more than the other though.

Yeah- glimmer of hope, thank you!

I did a quick, hand across and check of all connections, so I am not expecting to find a hose cracked - but never took them off and looked, could it getting gunked up with "meyo" mimic a vac. leak?

Thanks

Do you have any mods, like a Cold Air Intake that you didn't mention?

The only symptom you have is hard start when it is hot?

tried to check my CCV system, a little suction on the oil dipstick tube (photo with glove) and a little suction on the oil fill - one layer of plastic pulled in about an 1".

BUT - did notice a large "gurgling" sound with the dipstick removed, is this normal??

Pulled the tubes of the CCV system that are on top of the engine - nothing "mayo-ed" up.

again, my CCV system is about 1 year, 20K miles old (not that it cant fail at anytime)!

I have no Mods, or cold intake
Car is running fine, hard start on a warm (fine on hot, fine on cold), which I think is related to my fuel rail not holding pressure when the car is shut down. Which I replaced the elec. fuel pump and filter/regulator (twice) and dual temp sensor to try and correct but did not.

THANKS!

(this suction test was done on a cold running engine)

When you replaced the CCV system did you also replace the oil separator valve?

NO, I thought the:
BMW Crankcase Vent Valve (Cold Climate Version)
took the place of a oil separator valve??
this is what I replaced:

You are correct.

https://www.youtube.com/watch?v=V8xy3SNfnTQ

Suggested causes of fuel pressure drop are near the end.

Could Chain tensioner cause P1191 error?

Only noticed 2 times in last 50 or so start ups
COLD morning, idle sounds fine, start to accelerate and move - chattering sound, lasting only about 30 seconds. by the time I pull over, lift the hood, its gone.
First figuring its an old engine, cold thick oil and it was lifters rattling. Read others suspect this same chatter as chain tensioner?? Can chain tensioner skew DME to give me "rich" in one bank??

THANKS!

another clue??
I pulled the Air Distribution Piece that sits on the intake manifold - part of CCV system. A little bit of "mayo", but when I sprayed it out with compressed air WATER came out, including the top return? pipe.
I ordered a new CCV system. I plan to pull out, up to, and including the throttle body, clean and check for leaks and since it was noted to me that the CCV system can influence just one bank - I will replace it. I contemplated on the the "traditional PVC" cheat, but I would like to keep the BMW original to the engineers.

THANKS

I have a P1092 - but the car runs great. This weekend I did plugs, primary O2 and cleaned the MAF, but the code came back. My bank1 LTtrim runs about 7% and bank 2 runs between 7.8 and 8.5%. the ST trims bounce around while driving from +12 to -20. An indy shop did a smoke test, found no problem but said I need a new MAF. My CCV is still original (109K) but it doesn't seem to have excessive vacuum at the cap. Would like to hold off on CCV replacement till spring.

I am still searching for my issue.....
Did'nt get a chance to work on my new CCV replacement yet.
But I re-smoked my intake and valve cover - no leaks

assuming you cleaned your MAF? (get MAF cleaner at auto zone).

UPALLNIGHT pointed out this BMW service bulletin, - if your year is 03
http://www.bmwmotorsports.org/pdf/misc/120704.pdf

From my research: (none worked for me)
Many found there issue with the very common rip at the accordion turn of the Throttle Body boot -https://www.fcpeuro.com/products/bmw-air-mass-meter-boot-x5-13541440102
The Idle control valve is dirty
Gas cap not tight
Injector leaky
DISA issues

Check the ICV (Idle Control Valve). If it is sticking and not rattling when you shake it you can try to clean it but I would just replace it.

definitely need to do the CCV, ICV, fuel filter, etc - just would like to wait till spring. From the data I pulled, the MAF seems to respond perfectly with the RPM – sure seems to be measuring the airflow properly.

@Kevin, how long / miles have you had this code? My car runs perfectly but I don't want to ignore the code for too long and have something else fail - cats. etc

My code goes off and on (mostly on) since Nov, about 2500 miles. My car is also running perfect.

YES, I also am conserned about the cat having to deal with that extra fuel. And HATE seeing that "service" light. I am just less motivated to be under the hood in the cold...

As a bit of an experiment, I decided to scan / log my wife's CX-9 to get a better understanding of how a car that doesn't have a code reacts - perhaps a bit apples and oranges, but the basics of fuel and emissions controls seems to be fairly generic - oxygen sensors magnitudes seem to differ a bit between manufacture. Most of the reading see fairly similar to my X5 - for example if I plot MAF / RPM, the plots have the same pattern. The one that jumps out is long-term fuel trim. On my X5 the LT fuel trim will only change once every 10+ min. On the CX-9, it's changing every 20 sec or so.

According to a reference I found on the web:

The PCM’s definition of “short-term” is milliseconds, it acts incrementally, adding or subtracting fuel in small increments in an effort to hit the stoichiometric target.

the PCM is watching what’s happening in response to the changes in STFT. If STFT adds, for example, 3 percent fuel to the baseline and this makes the oxygen sensors happy, the PCM concludes that it ought to adjust the baseline. So it changes the “long term fuel trim” (LTFT). “Long term” is between 30 seconds and a minute. This creates a new baseline.

Based on the above, it would seem my LTFT is changing too slowly - up without knowing what is "normal" it's hard to tell.

@Kevin, Have you tried logging your LTFT? I'm using the Torque App and a BT OBDII which seems to work well.

Your on the right track but you guys need to introduce a variable to get the trim to make a change and then observe how it reacts.

If you add the numbers for the Short term fuel trim with the number for the long term fuel trim it should total close to 0 (zero).

So if the LTFT is 10, the STFT should be close to -10 so when you add them together it should be close to 0 (zero).

The LTFT on our X does not change as quickly as other cars, but it should change.

Next time you get a SES light check the freeze frame data. It will tell you what the engine was doing when it threw up the SES light.

btrvalik, assuming you have the same 3.0i I have .......

another member axgordon - (and the credit for this to him) said his trim errors were do to leaks in these 2 caps on the intake.
I just pulled one of mine off, (the other was kinda stuck and I wont pull that one off until I get the replacements). The cap I did pull was loose and all cracked - photo below. I taped it up temporarily and cleared my code I will see tomorrow if it comes back. I will be extremely happy if this was my culprit.

The 2 lower photos were from axgordon

and Yes I have tracked trims with iPhone app OBD fusion I think I even did a "freeze frame"- but I dont know what any of it means.......

#15
#17

RealOEM.com - Online BMW Parts Catalog

Just checked those plugs and mine seem fine. Since it's warm this afternoon, I decided to poke and prod at some of the vacuum lines with a stethoscope to see if I could hear a leak. Didn't find anything so I hopped back in the car to pull it back in and low and behold, the CEL was off!. Now the question is what the hell did it. The only thing that seemed to effect the engine was when I pulled the CCV hose off the valve cover. I didn't notice much of a RPM drop when I pulled it off, but the idle jumped a bit when I put it back on. Wonder of I had a bit of blockage in that line that opened up? I also gave the post car 02 sensor wiring a "shake" but the signals still look the same. My fuel trims also look about the same.

here is a good reference on fuel trims.. https://www.cartechbooks.com/techtips/fueltrim

Yep I did those 2 vac caps this spring, along with the 2 pieces of vac hose next to the ports with that white thing in the middle - and the entire SAP line from the passenger side of the manifold that ends on the "3rd port" that no arrow is pointing to, in your pic - the entire line is avail from BMW for $19 or so and has the 2 proper vac hose sections and a new hard line which is in the middle

Hey Kevin,

I found a Great Video on how to determine where your fuel pressure is leaking out. I think that is the reason for all your current problem.

Eric O of South Main Auto in upper state New York is a great mechanic and produces some of the best DIY videos for do it yourselvers.

Here's the link to his video. If you want to be a better diyer or mechanic, subscribe to his channel.

https://www.youtube.com/watch?v=DL8toqPcXKA

Thank you!
Can you verify I connected the fuel filter (which is also the regulator) properly?

I pulled the back seat off and verified the BLACK line went to the electric pump (passenger side) and the BLUE line went to the syphon pump (drivers side)

I then connected the BLACK line (electric pump) to the "IN" on the filter
and the BLUE line (syphon pump side) to the "rtn" on the filter
Both of these photos I found on line also have the BLUE line in the center - "rtn"

I replaced my CCV - the code came back AND after some short rides I gained a rough idle - guessing my idle control valve not seated properly?

Kevin, If you have proper rail pressure and the regulator changes the pressure with engine vacuum(or better yet vacuum pump) then you have the lines on correctly.

Idle control valve usually won't cause rough idle, more so not proper idle speed.

In park when I accelerate the pressure drops 1 or 2 Psi then back to 49psi
If the lines were mixed up could that be my issue of not holding pressure or would the car not run?

I am thinking something I did yesterday in replacing the CCV I caused my shaky idle. I pulled out everything in the intake upto and including the throttle body. New throttle body gasket, new intake boot with the accordion offset. I was in the engine all day yesterday and need a rest (mental) before diving into it again.

LOVE/HATE relationship with my X!

It would be better if you could pull the vacuum line(at the manifold) to the fuel pressure regulator and observe the rail pressure to be sure. And of course check the vacuum line to the regulator as well for leaks. Think you did that already but not sure ??

As far as the rough idle I would agree that is probably something to do with what you did when changing the CCCV. Did you replace vacuum hoses as well? maybe one of the hoses to the vacuum distribution manifold broke or cracked or doesn't fit properly?

Maybe read up a bit on how the fuel pressure regulator works, interesting and very useful to know.

We saw this with another X member on this forum. He installed a new gas filter but he mixed up the return line at the filter. I think he took off his Youtube video of the fuel pressure when the line was installed backward. At the back of the filter where there are two hoses, the blue line is the return line and the feeds is the black line. The return is attached to the hose barb that is in the center of the fule filter. The single hose and vacuum line is at the front of the filter. Hope this help. If you saw my video that I posted it was a leaky injector that was the cause of the loss of fuel pressure.

I pulled out everything up to and including the throttle body again, cleaned up that little rubber hose that the idle control vales pushes into. Put it all back together and still have that change in my idle - very slight, only in drive with my foot on the brake I feel a little roughness/jump in the idle. I conclude that I have made the intake "tighter" and less leaks which is making my trim code more focused and felt with the idle???
I am starting to suspect my MAF.
There is an after market new MAF for $18, might be worth it to use it as a tester.

YES - I am "throwing parts" at my issue..... a new car one pice at a time!!

Thanks for all the input

It might be just coincidence that the shaky idle started after you did the work on the CCCV but sounds suspicious. A MAF problem can be really hard (almost impossible) to diagnose without replacing with a known good unit to try. I wouldn't put any faith at all in a $18 MAF though. Any chance you can swap with somebody?

A bad MAF will not account for the drop in fuel pressure when the engine is off. You said you replaced the fuel pump, but you only replaced the pump itself. From that, I'm going to assume it wasn't a BMW oe pump from a BMW dealer, but an aftermarket pump.

The video that I posted for you showed three locations that you could be losing fuel pressure when the engine is off. You stated that you took the injectors out and turned on the ignition and didn't see any fuel leaking out of the injectors. Did you have the fuel gauge attached to the rail? If you did have the fuel gauge attached to the rail and you didn't observe any fuel leaking than the leak must either be in the fuel pressure regulator or the check valve at the fuel pump.

You stated that you replace the fuel filter twice so unless you connected something backward, I'm going to say that it isn't the fuel regulator.

That leave us with the fuel pump. Unless you performed the pinch off test as described in the video I'm going to say that you could have a bad check valve in the fuel pump.

All the stuff you are trying should cause codes on both banks. Per your first post the codes were only for bank two. I would be focusing on troubleshooting potential causes of a problem that would impact just bank two.

Yes, I agree. Its not plugs/coils or injectors because I switched them between banks. It's not my valve gasket, smoke tested it. I did a valve compression test - all within 200-205 psi.
Maybe I need to look at the exhaust manifold? (yuck- everything burnt on stuck) leak in the exhaust manifold gasket??

UPALLNIGHT- I have had my fuel pressure drop issue and searching for its cause much before this issue popped up. I suspected the issue when I would have a more difficult start on a warm engine. I started with changing the O-rings on the injectors and checking for leaks. Following instructions- when I went to "relieve the pressure on the rail" at the schrader valve I didn't get much if any fuel release. Did my reading and research and since my fuel pump was old/original and on my "list" - I changed it. I used OEM Pierburg pump. As far as I can tell the check valve has to be part of the pump?? and thus I have replaced it. I watched that video several time and MUCH appreciate your suggestions AND your commitment to me (and a lot others on this forum). i think I next need to separate the fuel line from the rail and test to see if pressure falls there.

Today I did a Freeze frame when the "service eng. soon" came on. looks like my short term in back 2 is WAY off???

Can you monitor the voltages on the 02 sensors on Bank 2. The combined value for the ST and LT for bank 2 is close to 14%. The LT appears to be right, but the ST is adding fuel to the mixture. With a LT in the positive the ST should be in the negative and not in the positive as the freeze frame data indicated. Did you replace any of the 02 sensors?

Which app are you using on your phone?

Here's a video I made for another X forum poster on 02 sensors. The video shows the precat and post cat sensors voltage as the engine is in close loop.

The precat sensors are on the left, the post cat sensors are on the right. Bank 1 is at the bottom of the screen and bank 2 is at the top of the screen.

Post cat sensors voltage should almost be constant without a large fluctuation in voltage. If your post cat sensors have a large fluctuation then you need to replace the catalytic converter(s).

https://www.youtube.com/watch?v=zyh_4SktmFM

ALL my O2 sensors are new, I am using OBD Fusion app
thanks

When you replaced the 02 sensors did you unclip the harness one at a time and install a new sensor, or did you unclip all the sensors wiring harness and went back to reclip them all once the new sensors were installed.

Wouldn't be the first time that a DIYer might have connected the sensors incorrectly.

One at a time, was carful not to mix them up.
Is there an easy way to check/make sure?

In post 3 you mentioned you changed the O2 sensors and it was shortly after that the code appeared. I suggest checking the connections to the sensors, especially the pre cat sensors, if all OK swap them out and see if code moves. As mentioned, I don't trust cheap sensors either. Since air/fuel mix is so critical I would go to OE or OEM sensors at some point.

I know you have done a smoke test twice. However, some vacuum leaks take an extended period of time to show up even with a constant 2-3 psi and tons of smoke for several minutes. Also, the vacuum leak could be internal which would not show up in a smoke test. Is the rough idle there when engine is cold and also when hot?

Have you done a leak down test?

Have you done the test in the video Upallnight posted where pressure gauge is connected to the fuel rail to test constant fuel pressure and especially the one where the engine is run and then shut off to see how fast the fuel pressure drops off?

Thanks.
The new O2 sensors were Bosh and the retailer was gracious enough to let me exchange the pre and post sensors in bank 2 under warentee to rule out defective sensors (which they said is VERY uncommon). I then even swaped the pre's once again and have reseated all of them several times.

My idle issue is only felt after warm up. I woke up in the middle of the night last night and realized I did not re-check the O ring on the oil dipstick that was replaced/reseated when I did the CCV kit last weekend. Could be a small vac leak there causing new idle issue??

I did not do a leak down test, I think that means a compression test where you leave the valve connect to see if it leaks down? I have no new oil consumption issues if that's any sign of valve problems.

My fuel rail pressure is consistent at idle with the car running, after shut down and the pump off it drops to zero in about 30-60 seconds.

When I say "smoke test" I am using a harbor freight hand pump, cigar and I blow into the tube for pressure. I have held pressure for about 3 min with my finger on the tube. Then either lifting my finger or lifting the oil fill cap - I get the "puff" of pressure release. I do notice the interior gets a linger of cigar smoke even with the windows and doors all closed.

A vacuum leak at dipstick seal would be there all the time nor would it cause a problem on only one back.

Yes, leak down test is opposite of compression test. Poor results are not limited to valves. Since you have done so many things, while it is long shot but---

Pressure dropping that fast is not normal. Should take 15-20 minutes to drop significantly and still would be a long way from zero. I would focus on fixing that as it may well be related to rough idle issue.

IMO smoke test you did would not be conclusive.

Pressure should take 15-20 minutes to drop significantly. Go to about 3 minutes into this video I posted earlier. https://www.youtube.com/watch?v=V8xy3SNfnTQ

Vacuum leak at dipstick would be all the time and affect both banks.

Yes, leak down test is opposite of compression test but does check more that just leaking valves. It is a long shot but---

IMO smoke test was not conclusive.

That said, your focus should be on correcting the fuel pressure bleed down. Rough idle could be symptom of fuel pressure issue.

thanks,
Yes, my car is not holding pressure as it should.
So, I assumed an injector leak - so I pulled the injectors and sat them on a towel with pressure and observed no fuel. Then I changed the regulator/filter (twice) and changed the fuel pump. So then again I had to assume I have a leaky injector (maybe it holds but leaks after its fired and doesn't quickly shut off??). So I switched injectors from bank 1 to bank 2 and my error did not migrate.

Appreciate all the suggestions/info you all are giving.

No garage and Boston winter weather - no fun fiddling around under the hood.
Reading about the Secondary air pump, I think I need to look that over? Does it pump air into the banks separately?

No, secondary air pump applies to both banks. Secondary air pump works when engine is cold for about a minute or so to heat up the cats faster so the engine goes to closed loop sooner.

Injector(s) could be sticking open some of the time but that pressure drop is awfully fast to be an injector and you aren't showing a cylinder misfire code.

Another thought I had (lately a lot of "middle of the night thoughts".
I replaced only the pump and reused the sending unit. There is a clear plastic accordion tube from the pump to the cover. I did not see any cracks or holes but I did not test it for pressure. If there was a hole in that tube, YES fuel would leak on the outbound as well, but it would just spray back into
the tank and I think our pumps pump at a greater pressure than required by the fuel rail? So in this theory, I could lose my prime if that tube leaked before The check valve of the pump yet it supplies the required pressure to run the car. But I still think my fuel issue is separate from trim issue.

Am I correct that running "rich" Will prematurely use up the catalytic converters lifespan?

Thanks!

Problems could well be unconnected but I would find the cause of the bleed down before doing anything more to address the stumbling.

Fuel pressure is controlled by fuel pressure regulator which would not be in the mix when the pump is off.

Yes, running rich can shorten life of cats but it would take a very rich condition for a long period of time. Cats get very hot and would burn off the majority of unburned fuel.

If your fuel pressure stays normal while engine is running for 5-10 minutes pump is working normally. I would block the return line, turn the key on to get pressure to normal and then turn the key off to see if it holds pressure. If it does that means the problem is on the other side.

Might be worthwhile to get a propane tank and the heater element that attaches. They put out an amazing amount of heat. Not expensive.

Thanks.
HATE pulling down the pan over the fuel filter. Can I block the return under the back seat behind the driver?

I changed the 4 cats about 4 days before the car was at a body shop
For 6 weeks (and I don't even know what shop - it was farmed out). Issue started shorty after I got the car back. First time I checked codes when the car returned, there were crazy multiple misfires. I cleared them all, my first thought was maybe the battery went dead and the car had trouble restarting. I HATE thinking like this, but.....my MAF or even my DME could have been swapped out with know problematic ones when the car was out of my possession. Although if you were looking for electronic parts- probably wouldn't take them from a 192k mile car??!!

That's why I stated in another post on fuel pump that it is better to pay the extra 20 bucks for the entire assembly and not fart around with switching out the fuel pump.

https://xoutpost.com/1084572-post13.html

Doesn't matter where you block it off, can do under hood if easier.

Anything that was swapped out would have to be a part that only causes a problem on bank 2.

There is a return under the hood??

Nope the return is with the fuel filter. Just like the regulator is no longer on the fuel rail, but built into the fuel filter. Careful with pinching off some of the lines because some of the line are hard plastic and if you try to pinch them, you will just crack them.

Back to my Original P code:
With my computer and BMW software DIS (or is it SSS?) my error code is P1191 and then it says - Trimming, oxygen sensor before cat, bank 2 ---too rich
with my iPhone app generic reader I get the code P1093

Just found this (about code P1191):
if the rear O2 sensor doesn’t agree with the front sensor. The most common problem that I have found with that code, is a air leak in the exhaust system. Normally at the flange were the converter bolts to the exhaust pipe. The leaks in that area do not let exhaust out. They suck in air. This give the back O2 sensor a false lean signal.

MY Flange is a MESS and one nut on bank 2 is totally rusted away.
Looked on RealOEM.com and they sell the bolts/nuts but it looks like the originals bolts are tacked to the flange of the headers? I am going to start another thread to see how others tackled removal of those bolts

THANKS!

I had a Muffler shop take out the pressed studs and replaces them with nuts/bolts.
He did not think there was a leak (although one of the nuts was completely rusted out holding the bank 2 flange). The muffler guy did concur that if there was a leak that air would get SUCKED in (I don't get that one.....) and it would affect that rear O2 sensor.

I cleared my codes and drove away. Several short rides went by and no service light and no "pending codes" on my iPhone reader. Then out for several more short rides and a "pending code" popped up on the Fusion reader. Then the pending code cleared on its own.

Can I still be optimistic that this could be my fix? Could it take some "pending codes" before the long and short term trims are back in sync?
Looking at my logs it looks like my long term are more steady at 5.468 and in the past have seen them as high as 8 on bank 2.

THANKS!!