Running with/without LTFT enabled....
Running with/without LTFT enabled.... What does the PCM do differently when running SD CL mode with the LTFT enabled vs. SD CL with the LTFT disabled and just using STFT? 
It will only correct your fuel trims on demand and not remember the cell that needed more or less fuel. So, it will be slower to react to an uncalibrated spot in the tune. Basically, the LTFT acts like a memory so if you get to that same load cell, it remembers that when you were there last time it needed x amount of correction and it adds that and then lets the stft change it if it needs to do so.
Ok. Sounds good. Now, correct me if I am wrong but the MAF helps compensate for temperature changes but mainly affects areas above 4K rpms. What helps to compensate for temperature changes below 4K RPMs?
I have been running a tune in SD and LTFTs disabled. Basically I have to "update" my tune every couple of days because my STFTs are going out of wack due to temperature changes occuring outside. I just want to get back to a time where I dont have to update my tune when weather changes, but I dont understand what part of the PCM compensates for this at lower RPM,s
Or do I have this all wrong?
I have been running a tune in SD and LTFTs disabled. Basically I have to "update" my tune every couple of days because my STFTs are going out of wack due to temperature changes occuring outside. I just want to get back to a time where I dont have to update my tune when weather changes, but I dont understand what part of the PCM compensates for this at lower RPM,s
Or do I have this all wrong?
Last edited by 99whitews6; Mar 18, 2008 at 10:40 AM.
Ok. Sounds good. Now, correct me if I am wrong but the MAF helps compensate for temperature changes but mainly affects areas above 4K rpms. What helps to compensate for temperature changes below 4K RPMs?
I have been running a tune in SD and LTFTs disabled. Basically I have to "update" my tune every couple of days because my STFTs are going out of wack due to temperature changes occuring outside. I just want to get back to a time where I dont have to update my tune when weather changes, but I dont understand what part of the PCM compensates for this at lower RPM,s
Thanks.
I have been running a tune in SD and LTFTs disabled. Basically I have to "update" my tune every couple of days because my STFTs are going out of wack due to temperature changes occuring outside. I just want to get back to a time where I dont have to update my tune when weather changes, but I dont understand what part of the PCM compensates for this at lower RPM,s
Thanks.
To my knowledge, the MAF is used throughout the RPM band when holding a consistent throttle position.
