Finally resolved some issues...but unequal fuel trims on WOT?

KaiserN54 · 08-28-2012, 10:39 AM

I have been trying to figure out why my car was hiccuping, stuttering, and surging, especially upon start up.

A new LPFP Sensor fixed it. Car runs smooth now, and NO hiccups.

I am running a custom map another user made for me- and I am happy to report trims under 30, even at 17.8 PSI! (E85/93 mix)

However, I have noticed that my trims are widely divergent. My First thought would be that my injectors are messing up...except that I recently replaced my bank 2 injectors...the very ones putting up higher trims.

Here are some logs:

Could this be an errant O2 sensor? Dirty DCI's?

Jeff@TopGearSolutions · 08-28-2012, 10:46 AM

I dont think they are unequal, yet.

I think it is because you graphed them in the same graph and since they may be over-lapping it scales one above the other.

As you can see your AFR are very close. Everything looks good to me. I think you are sweating a problem that doesn't exist. Enjoy your car

335okc · 08-28-2012, 10:48 AM

do you have meth? mine looks like that i think because meth distribution isn't always equal.

OpenFlash · 08-28-2012, 10:56 AM

Have a trim differential of ~10% isn't worrisome at all. Especially when running a strong mix of e85. Glad to see the LPFP replacement solved your issues

KaiserN54 · 08-28-2012, 11:02 AM

Quote:

Originally Posted by shiv@vishnu

Have a trim differential of ~10% isn't worrisome at all. Especially when running a strong mix of e85. Glad to see the LPFP replacement solved your issues

Well, there is still the issue of slow spool up. I believe you said that my WG's are on their way out, right? Do you still see that here?

GeorgiaTech335coupe · 08-28-2012, 01:42 PM

STFTs look normal. Bank 2 always seems to have to work harder.

themyst · 08-28-2012, 01:45 PM

Bank 2 is related to the rear turbo and it does appear this turbo does work harder than the front.

KaiserN54 · 08-28-2012, 07:19 PM

Quote:

Originally Posted by themyst

Bank 2 is related to the rear turbo and it does appear this turbo does work harder than the front.

How can tell this by fuel trims alone?

08-28-2012, 10:39 AM	#1
KaiserN54 First Lieutenant 29 Rep 332 Posts Drives: 2007 335I Join Date: Mar 2012 Location: Turbotown iTrader: (0)	Finally resolved some issues...but unequal fuel trims on WOT? I have been trying to figure out why my car was hiccuping, stuttering, and surging, especially upon start up. A new LPFP Sensor fixed it. Car runs smooth now, and NO hiccups. I am running a custom map another user made for me- and I am happy to report trims under 30, even at 17.8 PSI! (E85/93 mix) However, I have noticed that my trims are widely divergent. My First thought would be that my injectors are messing up...except that I recently replaced my bank 2 injectors...the very ones putting up higher trims. Here are some logs: Could this be an errant O2 sensor? Dirty DCI's? Attached Images
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08-28-2012, 10:46 AM	#2
Jeff@TopGearSolutions 3441 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	I dont think they are unequal, yet. I think it is because you graphed them in the same graph and since they may be over-lapping it scales one above the other. As you can see your AFR are very close. Everything looks good to me. I think you are sweating a problem that doesn't exist. Enjoy your car
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08-28-2012, 10:48 AM	#3
335okc Captain 42 Rep 659 Posts Drives: e90 335 Join Date: Feb 2011 Location: okc iTrader: (0)	do you have meth? mine looks like that i think because meth distribution isn't always equal.
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08-28-2012, 10:56 AM	#4
OpenFlash 1737 Rep 17,960 Posts Drives: A Lot Join Date: Sep 2006 Location: SF Bay, CA iTrader: (0) Garage List 2018 Ducati Panigal ... [0.00] 2016 Mazda CX5 [0.00] 2017 Aprilia Tuono ... [0.00] 2019 BMW M2 Competi ... [0.00] 2015 BMW M5 Competi ... [10.00] 2016 Ducati XDiavel S [0.00] 2016 AMG GT S [0.00] 2011 Ferrari 458 It ... [0.00] 2017 Charger Hellcat [0.00] 2015 KTM Super Duke ... [0.00] 2016 KTM RC390 [0.00]	Have a trim differential of ~10% isn't worrisome at all. Especially when running a strong mix of e85. Glad to see the LPFP replacement solved your issues
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08-28-2012, 01:42 PM	#6
GeorgiaTech335coupe Lieutenant Colonel 76 Rep 1,883 Posts Drives: Black BMW 335i coupe Join Date: Mar 2007 Location: USA iTrader: (0)	STFTs look normal. Bank 2 always seems to have to work harder. __________________ Legal Disclaimer: Anything I or anyone else says about my vehicle on this website(e90post.com or any affiliated or nonaffiliated sites), pertaining to modifications, is only to gain acceptance from my/our peers, and does not actually represent anything actually existing on my car, and thus, cannot be held against me in any issues, i.e. warranty claims, that may arise.
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08-28-2012, 01:45 PM	#7
themyst Major General 177 Rep 6,631 Posts Drives: '16 MK7 GTI Join Date: Feb 2009 Location: NYC iTrader: (8)	Bank 2 is related to the rear turbo and it does appear this turbo does work harder than the front. __________________ E90 LCI N54 6AT
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