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The Bacon Hauler (‘12 Cop Charger)
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Discussion Starter #1
I always thought both the fuel trims were ignored in open loop operation, but apparently that is not the case. The long term trims are used even in open loop mode, aka WOT driving.

989186
 

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The Bacon Hauler (‘12 Cop Charger)
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Discussion Starter #3
I know the STFT values are lost each time the ignition cycles, but do the LTFT values survive something like a battery swap?

I’m thinking they do not, and if that’s the case, they will not survive a tune flash either. And if that’s the case, this whole deal isnt as bad as I initially thought...although it does mean my WOT runs immediately after a tune flash will behave differently than those after the LTFTs have had a chance to be set...
 

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What's Mangement? I wouldn't believe something with such an obvious typo. I bet it's fake news from Russia.
 

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The Bacon Hauler (‘12 Cop Charger)
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Discussion Starter #5
What's Mangement? I wouldn't believe something with such an obvious typo. I bet it's fake news from Russia.
LOL! How fitting, that’s the study guide for engine techs taking the training courses at FCA. ??
 

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The Bacon Hauler (‘12 Cop Charger)
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Discussion Starter #7

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2015 RT 5.7 M6
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Probably...i grabbed it from the engine management workbook. I was Russian to respond. IIRC LTFT stays put in WOT and PE controls fueling (adds) based off the last LTFT value. I don't have a datalog handy at the moment.
 

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The Bacon Hauler (‘12 Cop Charger)
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Discussion Starter #9
Probably...i grabbed it from the engine management workbook. I was Russian to respond. IIRC LTFT stays put in WOT and PE controls fueling based off the last LTFT value. I don't have a datalog handy at the moment.
Look again, you grabbed it from the engine mangement workbook. :ROFLMAO:
 

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2015 RT 5.7 M6
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Well I just checked one of my logs and you can see LTFT and STFT dropout in WOT (in my tune I have WOT defined when pedal voltage is >2V).

PT...pedal voltage <2V

989217


WOT...pedal voltage >2V
989210
 

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The Bacon Hauler (‘12 Cop Charger)
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6,226 Posts
Discussion Starter #12
Lol guess the joke is on me because that is how I saved the filename when I posted the PDF.
That’s unfortunate, and I hate that it had to come to this, but you sir, ARE FIRED!!

Your stuff will be haphazardly tossed into an old paper ream box and set outside the front door. Please collect it before 5 AM yesterday or it will be incinerated with the rest of the garbage.

Have a nice day!
 

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Premium Member
The Bacon Hauler (‘12 Cop Charger)
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6,226 Posts
Discussion Starter #13
Well I just checked one of my logs and you can see LTFT and STFT dropout in WOT (in my tune I have WOT defined when pedal voltage is >2V).

PT...pedal voltage <2V

View attachment 989217

WOT...pedal voltage >2V
View attachment 989210
So you’re saying the FCA doc is incorrect?

which is it, either you’re wrong or they are...and frankly, I’m not sure how much I can trust you seeing as you just got fired from your last job.

(did they really just throw all your stuff in a box and leave it outside for you to pick up??)
 

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So you’re saying the FCA doc is incorrect?

which is it, either you’re wrong or they are...and frankly, I’m not sure how much I can trust you seeing as you just got fired from your last job.
From what I see on my logs, anytime I hit WOT the fuel trims drop out. Now, I have seen on HP tuners forum guys running into issues where the fuel trims remain at their last value during WOT.

Remember what Enginerd said about the workbooks...take what they say with a grain of salt and some lime. Kinda like the service manuals...they are not always correct. Heck, they show that the 5.7 and 6.4 have different VVT cam journal sizes...which they don't. If they did, we would not be able to swap cams.

Don't you have logging capabilities with the diablo? You should log the fuel trims as a function of pedal voltage. I think stock, the WOT pedal voltages is in the low 3V range.
 

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The Bacon Hauler (‘12 Cop Charger)
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Discussion Starter #17

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The Bacon Hauler (‘12 Cop Charger)
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Discussion Starter #18
From what I see on my logs, anytime I hit WOT the fuel trims drop out. Now, I have seen on HP tuners forum guys running into issues where the fuel trims remain at their last value during WOT.

Remember what Enginerd said about the workbooks...take what they say with a grain of salt and some lime. Kinda like the service manuals...they are not always correct. Heck, they show that the 5.7 and 6.4 have different VVT cam journal sizes...which they don't. If they did, we would not be able to swap cams.

Don't you have logging capabilities with the diablo? You should log the fuel trims as a function of pedal voltage. I think stock, the WOT pedal voltages is in the low 3V range.
I have countless logs with the fuel trims logged, but I’ve recently discovered something very salient about myself regarding my datalogs: I love making them; not so much reading thru them.
 

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2019 Dodge Challenger RT
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I came into this thread almost expecting some sort of LefT FooT joke and walked away actually learning a little something.
 

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2016 Jazz Blue A8 Scat
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694 Posts
I definitely have datalogs where LTFT is carried into WOT on my SCAT.

That neat little "reset adaptives" button comes in handy, but really the PCM is doing what it's supposed to. Correct for hardware wear and tear and any "uniqueness" of that particular engine package.
Things like casting flash in the intake path or wear in the valvetrain that reduces airflow. Injectors that are partially clogged or a fuel system that isn't quite keeping up, etc.

It can also make minor corrections for changes in fuel type/content or airflow from mods, but it is minor and doesn't always correct the way you want it to.
It does a lot better job maintaining stoich at part throttle for emissions than it does maintaining richer mixtures at WOT.
 
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