Fuel trim low stuck but mid works...
 

Hey guys. I've never had a problem logging trims but they've all been on 8's. Now this 9 is logging fuel trim mid and cycling at idle. Im sure mid is for cruise. Fuel trim low never moves from zero. Front o2 voltage is usually pegged at 0.9 as well so could this possibly be a broken front o2? Or does the ix log trims differently from the viii?

what are you logging with? give us all the details? custom rom? i'm going to assume its tuned that was without know anything more.

I'm logging with evoscan 2.9. The car is tuned by a shop. I just find it weird fuel trim mid is cycling at idle? I haven't messed with the request id's in evoscan...

Could be a custom ROM I suppose. Should I transfer all values over to one of tephras SD patched ROMs?

<p>Has anyone figured out this problem? I'm having this same issue of trying to log fuel trim low but evoscan 2.9 logs fuel trim mid instead. Evoscan shows fuel trim low is 0 which is incorrect. O2 feedback is 0. I appreciate any help.</p>

It's probably because your car is drawing more vacuum at idle than your low to mid cutoff so it's idling with the mid (cruise) closed loop setup. Look for a Closed Loop - LT Trim Control table or something similarly named. That's what it's called in Tephra. Check the max airflow (hz) you log at idle and adjust the values accordingly.