Hondata

Attaching a datalog and would like some clarification. My understanding was that both S.trim and L.trim were only in affect during closed loop operation. In the datalog you can see where it goes to WOT, S.trim goes to zero but it still shows 4% L.trim. Is this still affecting my fueling or is it only showing the value and not actually increasing my fuel?

Thanks,

closed loop simply means the o2 is active and affecting short term fuel trim.
Short term trim is calculated according to o2 feedback.
long term trim is just an overall average of short term trim.
Long term fuel trim is active at all times.
Short term fuel trim is active only while in closed loop

So you are saying that, because I drive at part throttle most of the time and my Ltrim is making adjustments for those parts of the map, it is also going to throw off the WOT part of the map???

My concern is that I had been set in closed loop while still trying to tune my WOT pulls, thinking that the trims wouldn't be affecting anything. I finally got a perfect fuel map but it shows 4% Ltrim the entire time.

So should I add 4% to the whole map and set my Ltrim max and min to zero to equal this out?

Alright well I added 4% to my tables where it runs in open loop, and set my L trim min and max to 0% to stop it from messing with my fuel anymore. We’ll see how it goes I guess.

2x0 wrote: Mon May 21, 2018 11:36 am So you are saying that, because I drive at part throttle most of the time and my Ltrim is making adjustments for those parts of the map, it is also going to throw off the WOT part of the map???

I am not certain that is totally true, I had the same impression you have, that LTRIM will only affect the part of the map that close loop is active.
I have seen that LTRIM tends to be the average of STRIM but lower (which makes totally sense) but i wasnt aware that, lets say I am running a 2% LTRIM that will also affect WOT operation.

Sounds interesting, if that is the case, I do not see why you would like to use it at all

Alright so here is what I did. I had my map spot on during a WOT pull, but it showed 4% Ltrim active the whole time.

I changed to open loop, and made my Ltrim min and max 0% to be sure it wouldn't affect anything. I then added 4% to my map to make up for the difference that Ltrim was supposedly doing during my pull.

And it ran pig-rich the whole time.

Ended up pulling the 4% back out and it's perfect again. So, apparently even though the log shows that Ltrim is in effect, it is not doing anything when operating in open loop parts of the map.

2x0 wrote: Wed May 23, 2018 5:42 am Ended up pulling the 4% back out and it's perfect again. So, apparently even though the log shows that Ltrim is in effect, it is not doing anything when operating in open loop parts of the map.

Exactly as I expected, the LTRIM might read 4% but it will NOT affect the areas outside closed loop operation, as also stated on the help and the link provided by Hondata

One cool thing that I would have tested is NOT switching to open loop as you did but remain in closed loop and to the same, as in WOT your closed loop would be turned off (based 'maximum map for closed loop value). that would proof that LTRIM is working properly and only applied when closed loop is not just enabled but active as well