Partial Throttle + Low Boost = Rich AFR
 

I have a Greddy Turbo kit with an upgraded GT3076R and CXRACING intercooler, 4 Bar OMNI MAP sensor, 850CC ID Injectors, Stock Fuel Pump, Electronic BCS connected where the Purge solenoid used to be, Blocked Purge solenoid hoses, Tial Q 50mm BOV, Kinugawa wastegate actuator, mishimoto catch can with check valve in the PCV solenoid hose.

My AEM failsafe gauge is connected at the downpipe where there isn't airflow from the wastegate. The AFR output from the gauge is sent to the ECU from the now delete rear O2 sensor wiring.

My issue is only at partial throttle between 0-5 psi. AFR is extremely rich (9.6-10.0). My tuner kept pulling fuel with no results. The car runs fine everywhere else, mid 11s at WOT, 14.7 at idle and cruise, as lean as possible (18-22 depending on where the reading is coming from) at deceleration.

Boost/vacuum leaks tested and it held 20 psi no problem. I was actually scared that the couplers might pop from the pressure.

My tuner is currently working on a new way to calculate fuel injection from boost, so far still running rich at partial throttle.

Attached log if anyone wants a look.

Anyone know what might cause this behavior?

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Hey ever got this issue fixed?

from that BRX's log, it seems to me that was just the maf scaling that was super rich from 2.5 to 3.9 Volt (and it doesnt seem SD based), and during those low boost low/medium load zone, the ecu was already swtiching to open loop so it didnt have a chance to correct it using STFT
in that case it seems just tuner error

but you should post a log to receive help