after ~month from swapping E8 ecu in evo3 got P0170 code. read that it's something related with scalings and fuel trims. before, all three trims were frozen at 0.1008. now the trims show -12.5 low, 0.8 mid and 0.1008 high but again they aren't cycling, as it was before the cel

my question is why the code came only after month or more and why the trims aren't cycling. and also how to fix it

 

Exhaust leak prior to the O2 sensor.

And...your LTFT Low is off. Might need a lot more injecotr scaling and/or MAF scaling. My guess is you are running an after market intake that is screwing with the MAF reading.

Try searching.......there is A LOT of info on this topic.

Paul

 

is exhaust leak one of the possible reason or is it for sure ?

p.s. injectors are scaled right I think, but dunno about maf

can it be the reason for trims aren't cycling ?


p.p.s. couldn't find any reasonable info with search

 

Yes an exhaust leak is a possible reason. I wouldn't have said it if it were not.

Yes, the MAF must be scaled properly.

Why would you ask a question, I give you answers and then you question the answers? I assure you, you won't get much help around here if you keep that up.

 

u using a 2 wire o2 sensor ???

 

yes, it's 2 wire, unheated

 

I always fit 4 wire sensors to evo1/2/3 when i fit later ecu plus always had to rescale the maf