LearningView - quick reference

[chimera]

Hi all,

 

I made this quick reference guide for LearningView, as I see the same questions pop up quite a bit about LV from newbies (including myself, I admit to only knowing the basics) and how to interpret it. I have been reading numerous articles to ensure I get the explanations correct, but as I'm also learning, happy to be set right for any mistakes in it. I realise there are a heap of websites (and some fairly good explanations on RR web site) but figured a single image with brief pointers might help explain the various fields quickly and easily. Bear in mind explanations should be as non-technical as possible and easy for anyone to understand (with minimal research themselves)

 

Feel free to chime in and correct me on any descriptions, or if anything important is missing and should be included etc. I'll update the original image as we go.

 

Cheers

 

http://www.chimera.co.nz/subaru/lv-explain.jpg

[serx7]

Not sure if this applies to all model years, but I believe the D range fuel trim (the 40+ g/s range in your example) gets applied to WOT/open loop, unless the tune is set up to not do that (eg: setting A/F Learning #1 Modify Airflow Limit (Max) < the top value listed in the A/F Learning #1 table.

[chimera]

If 'D' fuel trim was solely WOT/open loop, then surely there would never be any figure represented in the D fuel trim cell? (eg: there would be nothing to learn) I read somewhere there is a certain point above 40+ g/s where it changes over from closed to open loop, but that exact point isn't known. I'm sure I also read somewhere the engine will be in OL when it first starts up or when ECT levels are elevated.

[bnguyenbb6]

D is not solely WOT but it is applied to the open loop range. If your car was running 10% lean across the board from a vac leak, wouldn't you want it to also correct where it "can't" learn? The D learning range does just this. It can't correct itself in for exact ranges but that is how open loop is stays in line.

 

The engine is in a warm up open loop(7) when it first starts, then it goes to 10 for open loop or 8 for closed loop depending on how the car is running.

[serx7]

Just to clarify, my prev reply was simply intended to mention that the D trim (also) does include WOT since it does get applied to open loop (chimera's LV annotation in the OP indicated that the D range does -not- include WOT).

[chimera]

Ok so the D trim "range" does include open loop (according to romraider FAQ switch to open loop occurs somewhere around 60g/s) but when the ecu switches to open loop fueling does this trim value actually get used or does it rely solely on feedback of the MAF sensor alone? I'll re word that annotation if someone can confirm. According to 2 posts up that would be a yes if I'm reading that right?

 

 

Sent from my iPhone using Tapatalk

[bnguyenbb6]

It is applied and carries into open loop. If your fuel trims are "not in line" you shouldn't necessarily freak out unless they are pegged out. I would start investigating the reason for a high variance at 8-10% but even if your fuel trim is at -5%, just wait until the next tank of gas. Your fuel trim is supposed to be able to learn and adapt. That's the whole point of a MAF sensor and AF learning.

 

This also goes for IAM and FLKC. I'm not saying that -2.8 across the board or IAM of .6 is great but that is the ECU doing what it is supposed to be doing. Its trying to save the motor. IAM was made to save the motor incase of bad gas.

 

A "tune" is not always the answer; look for what is wrong.

[chimera]

I've updated the wording for WOT and open loop under fuel trims. Does this make more sense now? Hard to describe it in as few words as possible but still sound right!