Hey guys,
Let me start off by saying this problem is now fixed. But I still have questions. And please don’t say to put my accessport away because this wasn’t me being paranoid or over reacting. I have datalog and v Dyno proof that the stuck LTFTs made me lose 20-40 torque and 15-25 horsepower throughout the entire power band. I know I need to stop looking at my accessport so much but This is a legit topic that could affect other people.
so the other day I noticed my car was down on power . All my data logged readings looked normal except for LTFT. I noticed it was stuck at +10.94 regardless of throttle input. Which obviously isn’t supposed to happen. I ended up reloading the tune which forced it to relearn and now the ltft are adjusting again. Now the number fluctuates based on throttle input/airflow mass into the engine like it should. LTFT are split into sections based on how much air mass the computer sees. So different airflow mass readings causes the ltft to slightly change. I believe there’s about 6 sections all together. But that’s another topic.
The stuck LTFTs lead me to a few questions
1)what would cause the LTFT reading to become stuck on a single number like that?
2) because the LTFTs were stuck, does that mean the fueling was off? Or would the stft still adjust?
3) how do the fuel trims correlate to the afr. if the LTFT are saying +10. Does that mean that the actual afr are 10% lean.
Example- let’s say the afr was supposed to be 11.8 but the fuel trim was +10. 10% of 11.8 is 1.8. And adding fuel means the computer sensed a lean condition: Does that mean that the afr was actually more like 13.6 (11.8+1.8) causing the computer to add the 10% fuel to correct it back down to 11.8? Or do the trims and the afr not exactly correlate like that?
I’m asking because after resetting the learn the LTFT went as high as +17. But my ltft was stuck at +10.94. Meaning if the computer was no longer adjusting fuel due to the stuck ltft, that would have meant I was about 6% lean (please note the super high fuel trims we’re because I accidentally had far too much ethanol in my tank)
I was Monitoring the afrs During this and they were reading exactly what they were supposed to. Despite the fact that the LTFT were stuck and not adjusting
Let me start off by saying this problem is now fixed. But I still have questions. And please don’t say to put my accessport away because this wasn’t me being paranoid or over reacting. I have datalog and v Dyno proof that the stuck LTFTs made me lose 20-40 torque and 15-25 horsepower throughout the entire power band. I know I need to stop looking at my accessport so much but This is a legit topic that could affect other people.
so the other day I noticed my car was down on power . All my data logged readings looked normal except for LTFT. I noticed it was stuck at +10.94 regardless of throttle input. Which obviously isn’t supposed to happen. I ended up reloading the tune which forced it to relearn and now the ltft are adjusting again. Now the number fluctuates based on throttle input/airflow mass into the engine like it should. LTFT are split into sections based on how much air mass the computer sees. So different airflow mass readings causes the ltft to slightly change. I believe there’s about 6 sections all together. But that’s another topic.
The stuck LTFTs lead me to a few questions
1)what would cause the LTFT reading to become stuck on a single number like that?
2) because the LTFTs were stuck, does that mean the fueling was off? Or would the stft still adjust?
3) how do the fuel trims correlate to the afr. if the LTFT are saying +10. Does that mean that the actual afr are 10% lean.
Example- let’s say the afr was supposed to be 11.8 but the fuel trim was +10. 10% of 11.8 is 1.8. And adding fuel means the computer sensed a lean condition: Does that mean that the afr was actually more like 13.6 (11.8+1.8) causing the computer to add the 10% fuel to correct it back down to 11.8? Or do the trims and the afr not exactly correlate like that?
I’m asking because after resetting the learn the LTFT went as high as +17. But my ltft was stuck at +10.94. Meaning if the computer was no longer adjusting fuel due to the stuck ltft, that would have meant I was about 6% lean (please note the super high fuel trims we’re because I accidentally had far too much ethanol in my tank)
I was Monitoring the afrs During this and they were reading exactly what they were supposed to. Despite the fact that the LTFT were stuck and not adjusting
