[niemkij]

I have an 06 STi with mods:
3" turbo back exhaust with cats
Walbro fuel pump
Lightweight crank pulley
P&P intake and throttle body
High flow cross and up-pipe


After installing a WB O2 sensor post turbo, pre-cats I logged A/F ratios ~ 10.0 or richer at wide open throttle, 4th gear.

What would be the best way to lean this out a bit: injector flow scaling or Primary Open Loop Fueling values?

Would a reasonable approach to fuel tuning in general be to set the injector flow scaling such that the Primary Open Loop Fueling values approximate what is read by the WB O2 sensor, then adjust table values as desired?

If bigger injectors are installed, would one do the same starting with injector flow scaling at ~ the new injector rated flow, and also adjust the injector latency (if needed) and Throttle Tip-in Enrichment by the ratio of pre/post scaling values?

Also, does anyone know how the two tables Primary Open Loop Fueling A and B are used? Should they be the same?

I just started to learn about EM tuning. Any advice would be greately appreciated.

[williaty]

First thing to look at is what your OL Fuel targets actually are. At least one of the NA maps actually calls for AFRs that rich. If the car is basically hitting what that table calls for, then you're going to want to just modify the table.

Second, look at your AF Learning #1 A through D (recommend doing this with the Learning View program). Are they all positive? All negative? Random? Depending on what your fuel trims are doing, it can give you a little insight into what the actual source of the problem is.

Given your mod list, I don't see anything that screams fueling error there. You're running a stock intake and stock injectors. Depending on the trend of the fueling error, you'll adjust one or the other.

[niemkij]

Thanks, I will take a close look at the tables. The OL A Fuel table calls for A/F at WOT of 11.27 and OL B 10.6. I'm definately richer than that.

I will look into "Learning View"

Thanks again for your comments!