hey im running a bnr32 gtr ecu with a type 2 nistune runs great got my long term fuel trim to 0% runs good no missing or flat spots etc I just have unusual reporting from my o2 from cold start I see rich mix on my wideband till roughly 60'c coolant temp then Im seeing 16 afrs at cruise once warm if I give it a good thrash doesn't matter what gear just get a heap of load on an then come back to cruise it oscilates at 14-14.9 for the duration of the drive, if I shut car off and start hot same deal im seeing roughly 16afrs on the wideband and 0 reading on the stock o2 at cruise unless I give it some right foot and I have to get a bit of load on full boost anyway to get it to 14 afrs at cruise otherwise it will just sit at 16 afrs, and the stock o2 is showing lean during this condition so I dont think its an o2 issue as it knows its lean, after a thrash I see around 0.41v oscilating a bit as per normal and what you should expect, during the cruise at 16 afrs the reading on fuel map is showing the same 4 squares on the map as it does after I thrash it and its at 14 afrs, ive taken many logs can clearly see o2 is flat on the bottom at cruise 16 afrs have a 10km straight road here stayed 16 afrs the whole 10km at 100km around 1v on the tps and I give it wide open in 5th till I get full boost let off back to cruise and its oscilating around 14 afrs again and stays there for the duration of the drive (at cruise conditions) I see no difference in wide open afrs always come out the same.
one question is, will this harm the engine cruising at 16 afrs
number 2 what the heck could be causing it all my sensors read the same readings at cruise wether its showing 16 afrs or the 14 afrs expect for the obvious o2 sensors I have launch control off currently, and flex fuel can provide tune and logs if required
ive logged over and over trying to see something that changes after the thrashing but only the o2 readings change, I also notice cold start at idle its 16 afrs until I drive then get rich conditions into the 12s without boost but that switches at 60'c coolant temp to the 16 afrs and then idle hot is around 14s but not oscilating just stays solid 14.2 roughly
any help be much appreciated
o2 sensor readings
Moderator: Matt