Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - View Single Post - Leaning out around 4200-4500 RPM?

SprungtS · 10-20-2020, 06:21 PM

I've searched and come up with nothing, probably because I don't know of a way to search for this without getting tons of unrelated results. I feel like it's a fairly simple fix, and I'm just overlooking something.

Like the title says, almost exactly 4200-4500 RPM I'm consistently getting a lean condition. Commanding 12.12, getting as high as 12.98 at the peak on one pull, as high as 12.5-12.6 on others, right around 4350 RPM. I don't believe it's MAF scaling, considering those MAF V values are stretched out there and I'm not having issues slightly above and below that voltage. As soon as it hits 4500 RPM it's back at command AFR and slips just under command AFR for the remainder of the powerband.

I was thinking it may be something with the DI/PI system, but nothing is changing as far as I can tell at those RPM/loads. *Something* is happening at that moment, I just can't figure out what it is.

I'm not very far into tuning it, since I don't drive this car often. But I've got the rest of the fuel curve under WOT pretty much right where I want it: 11.7-12 AFR when commanding 12.12.

Stock airbox
Sprintex Supercharger
Gruppe-S header and overpipe
Invidia front pipe
Everything else is stock.

10-20-2020, 06:21 PM	#1
SprungtS Member Join Date: Oct 2020 Drives: 2020 BRZ tS, 2014 FR-S Monogram Location: Eastern NC Posts: 27 Thanks: 3 Thanked 9 Times in 5 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Leaning out around 4200-4500 RPM? I've searched and come up with nothing, probably because I don't know of a way to search for this without getting tons of unrelated results. I feel like it's a fairly simple fix, and I'm just overlooking something. Like the title says, almost exactly 4200-4500 RPM I'm consistently getting a lean condition. Commanding 12.12, getting as high as 12.98 at the peak on one pull, as high as 12.5-12.6 on others, right around 4350 RPM. I don't believe it's MAF scaling, considering those MAF V values are stretched out there and I'm not having issues slightly above and below that voltage. As soon as it hits 4500 RPM it's back at command AFR and slips just under command AFR for the remainder of the powerband. I was thinking it may be something with the DI/PI system, but nothing is changing as far as I can tell at those RPM/loads. Something is happening at that moment, I just can't figure out what it is. I'm not very far into tuning it, since I don't drive this car often. But I've got the rest of the fuel curve under WOT pretty much right where I want it: 11.7-12 AFR when commanding 12.12. Stock airbox Sprintex Supercharger Gruppe-S header and overpipe Invidia front pipe Everything else is stock.