Xoutpost.com

Xoutpost.com (https://xoutpost.com/forums.php)
-   X5 (E53) Forum (https://xoutpost.com/bmw-sav-forums/x5-e53-forum/)
-   -   P code expert?? What's the trim "system"? (https://xoutpost.com/bmw-sav-forums/x5-e53-forum/105439-p-code-expert-whats-trim-system.html)

kevinkay 01-03-2017 07:20 PM

P code expert?? What's the trim "system"?
 
1 Attachment(s)
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

80stech 01-03-2017 11:01 PM

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.

80stech 01-03-2017 11:03 PM

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

80stech 01-03-2017 11:07 PM

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.

80stech 01-04-2017 12:15 AM

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.

killcrap 01-04-2017 07:39 AM

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.

kevinkay 01-04-2017 08:34 AM

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!

killcrap 01-04-2017 11:38 AM

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.

80stech 01-04-2017 11:59 AM

Yikes! I forgot what the question was!

kevinkay 01-04-2017 02:16 PM

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

Still very much appreciate the guidance.


All times are GMT -4. The time now is 01:56 AM.

vBulletin, Copyright 2024, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.6.0
© 2017 Xoutpost.com. All rights reserved.