high ltft while running e85 with oft - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

flat4_86 · 12-20-2016, 11:20 AM

hey everyone, Ive had my OFT for about 5 months and after running the 91 stage 1 tune, which i enjoyed, I decided to try the stage 2 e85 tune and I love it! Ive been on it for about 5K miles. on my first tank my fuel trims looked good. ltft stayed at +3% and my stft stayed between -3-4%. and my second tank the stayed the same. but my ltft steadily has risen in the past few months. it goes up to +14%. ive been putting about 1.5 gallons of gas with every e85 fill up sinse I notice the rise of the Ltft and it brings it down to +3.12 and my Afr stays at 14.6.1 at idle. I haven't notice much knock, the most I've seen is -0.68 in low rpm 3d gear. I've done my oil changes every 3k miles and have cleaned my maf sensor in case My K&N filter was the issue but that didn't do anything. the only other modification my car has is a borla catback exhaust. ive read other threads, and some might say it could be an exhaust leak, but can my stock headers have a leak if they've never been touched? should I be worried? any helpful feedback is welcomed and thank you in advance.

phrosty · 12-21-2016, 03:36 PM

I suppose it is is possible nothing is wrong with your car. Can you verify what E% your E85 is? +10% LTFT would indicate something like true 85%, which while rare is not unheard of.

Other than that, check O2 sensor is the last "easy" thing you can do.

Crazy Asylum · 12-22-2016, 09:54 AM

You could always run an ethanol content test on your next fill-up. Perhaps your fuel station has been stocking increasingly higher ethanol content e85.

Keep in mind that on your first tank you may have had 2 or so gallons of 91 remaining in the tank. Your next fill-up after that, the remaining fuel would have a high e content requiring 91 to be added to keep a similar mix.

Nah · 12-22-2016, 11:49 PM

Scale your MAF

flat4_86 · 01-22-2017, 12:47 AM

Here are some datalogs I did on stage 2 e85 and stage1 91 octane

http://www.datazap.me/u/blades805/lo...0?log=0&data=1

12-20-2016, 11:20 AM	#1
flat4_86 Junior Member Join Date: Dec 2016 Drives: 2015 subaru Brz Location: Oxnard, Ca Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	high ltft while running e85 with oft hey everyone, Ive had my OFT for about 5 months and after running the 91 stage 1 tune, which i enjoyed, I decided to try the stage 2 e85 tune and I love it! Ive been on it for about 5K miles. on my first tank my fuel trims looked good. ltft stayed at +3% and my stft stayed between -3-4%. and my second tank the stayed the same. but my ltft steadily has risen in the past few months. it goes up to +14%. ive been putting about 1.5 gallons of gas with every e85 fill up sinse I notice the rise of the Ltft and it brings it down to +3.12 and my Afr stays at 14.6.1 at idle. I haven't notice much knock, the most I've seen is -0.68 in low rpm 3d gear. I've done my oil changes every 3k miles and have cleaned my maf sensor in case My K&N filter was the issue but that didn't do anything. the only other modification my car has is a borla catback exhaust. ive read other threads, and some might say it could be an exhaust leak, but can my stock headers have a leak if they've never been touched? should I be worried? any helpful feedback is welcomed and thank you in advance. Last edited by flat4_86; 12-20-2016 at 03:27 PM.

12-21-2016, 03:36 PM	#2
phrosty Senior Member Join Date: Apr 2013 Drives: 2013 FR-S Location: Seattle Posts: 806 Thanks: 202 Thanked 320 Times in 199 Posts Mentioned: 18 Post(s) Tagged: 1 Thread(s)	I suppose it is is possible nothing is wrong with your car. Can you verify what E% your E85 is? +10% LTFT would indicate something like true 85%, which while rare is not unheard of. Other than that, check O2 sensor is the last "easy" thing you can do. __________________ 2013 Whiteout 6AT FR-S \| Perrin Inlet Tube + 2.75" CAI \| OpenFlash Header \| P&L Catback \| 4.88 Final Drive \| Dialed in OFT 2.0x Stage 2 E85 \| 18x8 Enkei Raijin + 225/40 Michelin Pilot Super Sport \| 17x7 Stock + 215/45 Michelin X-Ice Xi-2

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12-22-2016, 09:54 AM	#3
Crazy Asylum Member Join Date: May 2016 Drives: 2016 FR-S Raven Location: Northern VA Posts: 29 Thanks: 1 Thanked 4 Times in 4 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	You could always run an ethanol content test on your next fill-up. Perhaps your fuel station has been stocking increasingly higher ethanol content e85. Keep in mind that on your first tank you may have had 2 or so gallons of 91 remaining in the tank. Your next fill-up after that, the remaining fuel would have a high e content requiring 91 to be added to keep a similar mix.

12-22-2016, 11:49 PM	#4
Nah Senior Member Join Date: Jan 2016 Drives: 2013 Scion Frs 6mt Location: Florida Posts: 234 Thanks: 85 Thanked 48 Times in 32 Posts Mentioned: 1 Post(s) Tagged: 2 Thread(s)	Scale your MAF

01-22-2017, 12:47 AM	#5
flat4_86 Junior Member Join Date: Dec 2016 Drives: 2015 subaru Brz Location: Oxnard, Ca Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Here are some datalogs I did on stage 2 e85 and stage1 91 octane http://www.datazap.me/u/blades805/lo...0?log=0&data=1

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