Diagnosing AFR Issue
 

So to keep things simple and to the point I have an AFR issue only related to light throttle. AFR either goes pig rich or stupid lean 11afr or 17afr on light throttle.. Always a toss up and its one or the other. By monitoring dashhawk I noticed that without the issue happening the primary O2 sensor will read anywhere between 700mv-800mv. However, when the AFR freaks out the sensor will be reading very very low. Anywhere between 15mv-70mv which I imagine is a dead sensor. I'm not about to throw parts at the car unless I'm sure it's the issue. The car is maintained and other sensors such as the MAF are spotless.

Other odd note: doesn't happen above 46mph.

Also, does anyone know if on the bottom right corner of my Dashhawk means 'C' for Closed Loop and 'O' for Open Loop? Can't seem to find that answer anywhere. Even on MSD's website lol. Nor the manual.

watch the commanded afr and see what it does.

Ill try that next time. Will have to dig through the dashhawk to see if it reads it.

I saw 3 different commanded AFR #'s. The standard 14.7 which is normal. But it would either jump to 13.5 or 16.5 commanded randomly for some time. All at cruise under light throttle.

i believe you correct about closed vs. open loop on the dashhawk

Wonder why it jumps from closed to open like that?

calibration issues

Are you sure its mph and not rpm related? Are you entering open loop at a specific rpm?

if for some reason your are hitting enough pressure from the turbo to trigger pe mode in your tune....which would make it go from closed loop to open loop......COT settings could change commaded fuel....

how far off are your fuel trims? I've seen commanded AFR change to swing the trims back in line.

It feels like it's MPH related. Not sure how I could diagnose that? Open loop is always random and when it does this AFR issue happens. Only at light throttle from say 10mph to 46. I'm probably just gonna keep this between my tuner and I as this appears to be some sort of bug. I dont know much at all when it comes to the tuning aspect of it.

Wouldn't know as I do not have HP Tuners. Just gonna take it up with my tuner. No worries.

Good idea he'll get ya squared away.

if the kpa trigger is set too low it will do this. {pe trigger} or the tps trigger is set wrong. set the cat test and rear o2 test to disable, and set the cot temps to stock, but disable the activity of it.

Thanks for the input. I appreciate it.