How do you know if youo need to have your MAF rescaled? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

guybo · 04-18-2017, 08:07 PM

So I had a problem with my intake where the LTFT was very high negative at idle, good as soon as I got on the throttle. I thought I needed my MAF rescaled but now my LTFT is always in a good range after I fixed something and changed a few things. Do I need my MAF rescaled?

Is it just to fix bad fuel trims or is there something else it does too?

steve99 · 04-19-2017, 12:02 AM

If the maf scaling was fine before the fault\leak then after you fixed the issues it will be fine

If ltft is say less than 5% throughout rpm range and afr and commanded afr follow each other within say 5% during wot runs then all good

guybo · 04-19-2017, 09:43 PM

OK, thx @steve990 My AFR and LTFT are looking fine well within range throughout the rev range. I'm running an Injen SP intake and even at idle it's doing a lot better now that I have figured it out.

04-18-2017, 08:07 PM	#1
guybo Huge E85 fan! Join Date: May 2016 Drives: 2016 Scion FRS Location: Tampa, FL, USA Posts: 1,850 Thanks: 539 Thanked 1,010 Times in 605 Posts Mentioned: 32 Post(s) Tagged: 0 Thread(s)	How do you know if youo need to have your MAF rescaled? So I had a problem with my intake where the LTFT was very high negative at idle, good as soon as I got on the throttle. I thought I needed my MAF rescaled but now my LTFT is always in a good range after I fixed something and changed a few things. Do I need my MAF rescaled? Is it just to fix bad fuel trims or is there something else it does too?

04-19-2017, 12:02 AM	#2
steve99 Banned Join Date: Dec 2013 Drives: FT86 Location: Australia Posts: 7,998 Thanks: 1,035 Thanked 4,987 Times in 2,981 Posts Mentioned: 598 Post(s) Tagged: 2 Thread(s)	If the maf scaling was fine before the fault\leak then after you fixed the issues it will be fine If ltft is say less than 5% throughout rpm range and afr and commanded afr follow each other within say 5% during wot runs then all good

04-19-2017, 09:43 PM	#3
guybo Huge E85 fan! Join Date: May 2016 Drives: 2016 Scion FRS Location: Tampa, FL, USA Posts: 1,850 Thanks: 539 Thanked 1,010 Times in 605 Posts Mentioned: 32 Post(s) Tagged: 0 Thread(s)	OK, thx @steve990 My AFR and LTFT are looking fine well within range throughout the rev range. I'm running an Injen SP intake and even at idle it's doing a lot better now that I have figured it out.

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