This is what my data logging seems to be showing but since I couldn't seem to find this documented anywhere I just wanted to confirm with the group.

 

I've seen open loop on mine below 3V. I think open loop trigger conditions are certain TPS and rpm values.

 

Makes sense there would be more than one factor involved. My data is all at partial throttle and low to mid engine speeds so what showed most consistently was that correction went to 100% and my AFR went too rich every time MAF read >3v.

 

Looking closer at my data the switch appears to happen somewhere between 3 and 3.3 volts. First graph is stock data. Second graph is after turbo but before MAF table tuning.

 

I'm not sure all the settings but at some point there is a "max rpm" in which it will switch to open loop based on rpm and not load.

The one I just tuned last weekend was open loop below 3v but this was also going WOT for tuning boost.

 

sorry for my ignorance
but
what's the best way to see immediately if it's in open or closed loop ???

 

If you are logging you can look at the obdII open loop switch (it will say on or off during the current state) or you can look at o2 corrections. They will read 100 when you are in open loop (since they are not doing any work).

 

i was told by uprev that the ecu switches to open loop whenever the afr targets. are below 14.4. i tried this out myself, to make a test and tune map, and it works as they said

 

The graphs above show corrections being applied when the AFR < 14.

 

herm derp. thats strange. when I set my targets to 14.4, my fuel comp sits at 100

 

Maybe just coincidence. If you want to test it again you could just set AFR < 14.4 in a low load, low rpm cell. There are probably multiple triggers for open loop all meant to detect conditions where things are happening too fast for closed loop to work properly.

 

I've noticed the same on my logs.

3V MAF seems to trigger open loop under any throttling condition, and WOT will trigger it regardless of MAF voltage.

 

I think what I was seeing was coincidental. I swapped a HPX PMAS maf for the stock maf. With that I saw the switch from closed to open happen around 2.5V on one tune and around 2.66V on another. I think there are a variety of conditions that trigger open loop as suggested in the earlier posts. I don't think MAF voltage per say is one of those triggers otherwise I wouldn't see it happening at different voltages for different tunes. Rather I think the MAF voltage is a surrogate for the true triggers that the ECU uses.