Rough Idle and Misfire- INPA Fuel trims

[dk500]

I have absolutely no idea what I am looking at, other than it looks weird. Any ideas on what this means? I have a rough idle and misfire when at idle and the car is warm/hot. 6 months ago a mechanic said the car wasn't leaving open loop.

IMG_6863.jpg

IMG_6864.jpg

[gmak]

The first picture looks absolutely fine. It's your O2 sensors and the Additive (STFT) and Multiplicative (LTFT) fuel trims for Banks 1 and 2. The last charts at the bottom are the LTFT. The ones just above it are the STFT.

the second picture is only part of the page - Note that INPA sometimes doesn't report the correct numbers on this page - with the MAF, air flow etc... If you want to see what is running rough, I believe that it is <F6> in status that shows the roughness index for each cylinder.

But why don't you go into <F1> for error codes and see what is really wrong - i.e. it will tell you which cylinders are misfiring.

[dk500]

The first picture looks absolutely fine. It's your O2 sensors and the Additive (STFT) and Multiplicative (LTFT) fuel trims for Banks 1 and 2. The last charts at the bottom are the LTFT. The ones just above it are the STFT.

the second picture is only part of the page - Note that INPA sometimes doesn't report the correct numbers on this page - with the MAF, air flow etc... If you want to see what is running rough, I believe that it is <F6> in status that shows the roughness index for each cylinder.

But why don't you go into <F1> for error codes and see what is really wrong - i.e. it will tell you which cylinders are misfiring.

No codes stored or pending. I'll check the roughness index. I did clear adaptions and it seemed to fix it for now...

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Do you know how I can make this english?

[bmwE38r]

Hi I want to ask in this post about furl trims In literetaure i found that STFT is multplicative,and LTFT is additive,a this is true? Because here in forum I think,that someone says wrong,thay STFT is additive and LTFT is multiplicative?:o and lambda integrator is STFT whats happening right now,yea?

[gmak]

LTFT is what the DME is doing to every drop of gas all the time. It is an adjustment to compensate for errors in airflow and fuel flow data (ie the DME thinks it's putting in 1 g/s but the injectors are only doing 0.95 g/sec - not real figures just an example). The STFT is a 'right now' adjustment to reflect changing conditions. Mine goes back and forth over zero (ie negative to positive) depending on the load on the engine and the driving condition.

SO, LTFT is likely multiplicative - ie the DME knows to release 105% of the fuel (or only 96% of the fuel) that the data table tells it to to compensate for mechanical error. The STFT is additive. The DME listens to the O2 sensors which say add a bit more or subtract a bit more fuel because nothing is perfect in this analog world and little adjustments are always needed. If the DME finds that it is always doing the same STFT, then the LTFT gets adjusted so that the STFT goes back to cycling around zero.

Does this help?

(Also, there is some literature out there that is just wrong).

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Do you know how I can make this english?

There should be a DIY around on how to do it. IIRC, it involves INPA.ini; OBD.ini; You need Language to be ENGLISCH (Note spelling), and Variante to be ENGLISH (note spelling). This assumes that yuu have all three sets of data files, german, english and english metric.

[bmwE38r]

Yes,this is help My engine m62b44 and it runs perfectly on cold and warmed upIn my situation I have a additive(STFT) postive,its about 8-10,but my multiplicative(LTFT) is -10.Why ita condtradicting? Short term is add fuel,but for long term no need fuel,and why short term dont go to the base point(around 0) I know,thats if values contradics,then maf sensnor faulty,thats true? Also what values is good? I know that perceft is when is about 0,but if values goes around -8 to +8 thats normal,or thats bad?

[gmak]

Multiplicative is showing that you are running rich. You have too much fuel for the amount of air, and your ECU /DME reduces the amount of fuel continuously. As I've said to you in PMs, the STFT will vary. The fact that the STFT is positive now shows that the LTFT will become less negative (if the STFT stays at his level). WHen the LTFT is where it should be, the STFT will be closer to zero.

[bmwE38r]

I understand what you say,but thats is strange for me My LTFT is negative,and I udrestand that now my ecu MAPs is need to be leaned,because engine runs so rich(in short,now engine runs on less fuel map) but my STFT whants add fuel,why? LTFT greats new map with less fuel(values -8 -10) but STFT trying to rich mixture:/
http://wiki.bavariantechnic.com/inde...re_Adaptations here shows,that when values contradicts,then sometimes can be faulty maf sensnor,thats true

[PiotrC70]

Uninstall your INPA German and select English(UK) as the language setting during the install. I've reinstalled mine before with English US but everything referenced is always metric so I went back to UK.

[bmwE38r]

^?

[nealbui2000]

Hi PiotrC70
Could you help me how to change my inpa in German to English please. I currently have the German version and have no idea what I'm looking at.

Thank you

[540-S3]

+1

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