Every starlet i've seen with CT turbo and stock ecu, FRP, pump, runs rich as F*ck over 0.8bar. Mine goes richer than 10:1. Only with lower fuel pressure of 2bars, with vac. hose attached, i can hold it near 10-10,5 at high rpm. Only with a bigger turbo like T25 the stock ecu is fueling "lean" (~12.5:1) I say, buy an wideband, check that fueling is ok and leave the FCD there if it's wotking. But 1 bar on ct is near the limit of the turbo, so maybe good time to go for a td04 or something...