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Preface:
I have two naturally aspirated Acura's, a TL and a ZDX. The STFT and LTFT are always within the ~0-5% range. My only perspective is the live view of these readings when I drive my cars.
Question:
Since the IS F is also naturally aspirated, shouldn't the STFT and LTFT also be within the ~0-5% range? From my observations, the LTFT are always pretty far off, around the ~12-20% range. Lately, as I've been driving more, and driving harder with a heavier foot, the LTFT appear to be transitioning closer towards 0%. I haven't experienced any circumstances indicating that the engine is not performing as intended, either. Would a cracked header be affecting the LTFT, or is it a different aspect? What can I actually do in order to figure out if this is some sort of intake or exhaust issue? My limited experience with tuning and datalogging is only with turbocharged vehicles, as I used to own a 2004 STi for 13 years (Tactrix, Romraider, Cobb). I'm not entirely sure how much different N/A is compared to forced induction in this regard. What insight do the members with knowledge have on this topic?
(Perfect, I have an old picture from 6/2023 demonstrating exactly what I'm referring to.)
Data log/Monitor the primary O2 sensors' voltages as well, they should be constantly changing with readings between .2v-.8v. But negative LTFT means system is thinking that it's running rich. Intake/Vacuum leaks usually result in lean condition. Normal LTFT ideally should be between -10% TO +10% at idle.
Data log/Monitor the primary O2 sensors' voltages as well, they should be constantly changing with readings between .2v-.8v. But negative LTFT means system is thinking that it's running rich. Intake/Vacuum leaks usually result in lean condition. Normal LTFT ideally should be between -10% TO +10% at idle.
Well, it would seem that the car fixed itself... I don't know how, and I won't question it. Nothing has changed from my input. I checked the voltages today, and they were constant.
The ECU learns and adjusts based on what it's seeing. It will adjust to keep those numbers in check, up to certain point course. If there's an actual fault and it cannot compensate anymore, a code will pop up. Those numbers will be constantly changing under load. The numbers at idle in park are just as important, if not more. Good thing it's fixed now.
The ECU learns and adjusts based on what it's seeing. It will adjust to keep those numbers in check, up to certain point course. If there's an actual fault and it cannot compensate anymore, a code will pop up. Those numbers will be constantly changing under load. The numbers at idle in park are just as important, if not more. Good thing it's fixed now.
I lied... I only realized about an hour ago what I actually did. It's such a routine part of what I do that I didn't register the act as an input towards the solution. The second last time that I fueled the car, I also added a bottle of Seafoam injector cleaner. That's what has aided with the fuel trims. All of my cars have high miles, so at least once a year, I add a bottle of Seafoam injector cleaner, and Seafoam motor treatment.
The car is operating optimally for the moment being.
08-29-24, 01:51 PM
IS F's 2UR-GSE and LTFT, Long Term Fuel Trims
