Help Me understand fuel trims STFT logs inside

N54andS63TU · 11-21-2020, 04:21 AM

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Mods FBO + inlets outlets stage 2 turbos, stage 2 lpfp E45
Can someone take a look at this log and tell me if it looks okay. I was tuned 2 years ago just to make sure things are still good.
Running E45 fuel trims go negative -15 are those numbers ok?
Thank you in advance

https://datazap.me/u/azizzlol/log-16...51-159-156-146

Tunafish · 11-21-2020, 10:16 AM

You are far away from the right category..

From the little details in your log everything looks good except for one instance where you from went positive.. I am not sure what happened there but you went lean all of the sudden.. . Your short term fuel trims should stay under 30% one way or the other. The difference between the two should be below 10% variance.. And its better to be in the negative then positive.. Negative is taking away fuel which means you are running on the rich side and car is correcting.. Positive is running lean and car is adding more fuel to richen mixture.. Do you know why you went lean? Maybe let off gas?

N54andS63TU · 11-21-2020, 03:27 PM

Quote:

Originally Posted by Tunafish

You are far away from the right category..

From the little details in your log everything looks good except for one instance where you from went positive.. I am not sure what happened there but you went lean all of the sudden.. . Your short term fuel trims should stay under 30% one way or the other. The difference between the two should be below 10% variance.. And its better to be in the negative then positive.. Negative is taking away fuel which means you are running on the rich side and car is correcting.. Positive is running lean and car is adding more fuel to richen mixture.. Do you know why you went lean? Maybe let off gas?

Uh yeah I remember letting gas go for a second when it spinned a little. My bad I should've have done better log, I will do it later again.
I will do my research more on STFTs looking at other people's logs got me worried, running -15 or -20% stft is pretty normal on my e50 tune right? And also there's some timing pulls about 3-4 degree. I shouldn't be worries much?

Btw car has new plugs gapped 0.022, new coils, new hpfp.

NoGuru · 11-21-2020, 07:42 PM

Your LPFP is sort of struggling. Might want to look into larger lines or new FPR.

BSM n54iS · 11-22-2020, 12:44 AM

Wrong section lol

vladskies · 11-22-2020, 02:06 AM

Use the link down below, takes you to the right part of the forum to ask this question

Avoid using marketplace for suggestions

Wish ya the best in finding your problem

https://www.e90post.com/forums/forumdisplay.php?f=58

11-21-2020, 04:21 AM	#1
N54andS63TU Private First Class 10 Rep 115 Posts Drives: bmw e92 6speedMT! Join Date: Nov 2011 Location: brooklyn iTrader: (0)	Help Me understand fuel trims STFT logs inside BIMMERPOST / Classifieds Asking Price: None Item Interest Mods FBO + inlets outlets stage 2 turbos, stage 2 lpfp E45 Can someone take a look at this log and tell me if it looks okay. I was tuned 2 years ago just to make sure things are still good. Running E45 fuel trims go negative -15 are those numbers ok? Thank you in advance https://datazap.me/u/azizzlol/log-16...51-159-156-146
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11-21-2020, 10:16 AM	#2
Tunafish Banned 262 Rep 817 Posts Drives: BMW 335i N55 Join Date: Dec 2019 Location: Home iTrader: (0)	You are far away from the right category.. From the little details in your log everything looks good except for one instance where you from went positive.. I am not sure what happened there but you went lean all of the sudden.. . Your short term fuel trims should stay under 30% one way or the other. The difference between the two should be below 10% variance.. And its better to be in the negative then positive.. Negative is taking away fuel which means you are running on the rich side and car is correcting.. Positive is running lean and car is adding more fuel to richen mixture.. Do you know why you went lean? Maybe let off gas?
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11-21-2020, 07:42 PM	#4
NoGuru Major 779 Rep 1,434 Posts Drives: 335is Join Date: Apr 2017 Location: MI iTrader: (0) Garage List 2021 Chevy Silverad ... [0.00] 2014 CTS [0.00] 2011 335is [0.00]	Your LPFP is sort of struggling. Might want to look into larger lines or new FPR. __________________ 2011 335is DCT BQ Tuning / BMS CAI / VRSF kittyless DP's / Synapse BOV and charge pipe / 7" VRSF Race FMIC / Walbro 535 and 450 on BMP4 / E90 tune / Diff Brace / PR Coils / Relocation Inlets / DAW Stage3+ Turbos / MMP port injection / xHP Stage 3 / FPR and -6 fuel lines
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11-22-2020, 12:44 AM	#5
BSM n54iS Brigadier General 2682 Rep 4,203 Posts Drives: '11 335is \| '16 Macan Turbo Join Date: Aug 2015 Location: Everywhere and Nowhere iTrader: (7)	Wrong section lol __________________ '11 335is BSM MT "BMW Performance Editon" \| '16 Porsche Macan Turbo GruppeM CF Intake \| AR Resonated DP \| ER CP \| Turbosmart RacePort BOV \| Cobb FMIC \| RB Inlets \| RB External Mishi/Turner OCC \| Michelin PS4 \| BMW Performance Springs/Bilstein B8 + Dinan & M3 bits \| BMW Brembo BBK \| BMW Performance CF Spoiler \| BMW Performance CF Lip \| BMW Performance Alcantara \| PS Designs GTS Armrest \| AG H6-40 \| Rear Seat Delete
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11-22-2020, 02:06 AM	#6
vladskies Private First Class 26 Rep 171 Posts Drives: 2008 335i e90 Join Date: Dec 2018 Location: Fremont, CA iTrader: (2)	Use the link down below, takes you to the right part of the forum to ask this question Avoid using marketplace for suggestions Wish ya the best in finding your problem https://www.e90post.com/forums/forumdisplay.php?f=58
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