Are you kidding? You need to know the total fuel trim to diagnose.
'05 Lexus 4.7 Long Fuel Trim report
- Thread starter dblshock
- Start date
Okay. Then explain how that works?
These 4.7 MAF sensors are Hitachi, I found these @$33.00 I might take the flier on one..
e.Bay sensor
e.Bay sensor
STFT + LTFT anything over 10+/- then you would start to be concerned. If the LTFT is -6 and the STFT is +6 that comes out 0. What is there to be concerned about?
I thought they were really the same data reported over different time spans and that each would ideally total zero for optimal stoichiometric ratio FT.
I stand corrected, after looking further into this you are correct...I'll have to recalculate based on this equation.
I tried this on my own truck on a drive yesterday and it's very tricky since the short term moves around a lot. You kind of have to observe trends, different amounts of load affect where the short term trims go, but in general it seemed that most of the time (at least under load or cruising) the short terms were - making the total closer to 0 than the long term, but at idle or coasting it still seems to usually be close to +10 or more, suggesting a minor vacuum leak in my case, just as I suspected based on what the long terms were doing.
Not exactly.....STFT are just the fine tuning of what long term trend was already learned which is displayed as the LTFT values. Unless the LTFT's are maxed out one way or the other.....STFT usually hover around zero +/- 5% once the LTFT's have had time to learn & populate across the entire fueling map.
The only time I add the 2 together is WHEN the LTFT are maxed out.
I was pretty sure I had this figured out after a good chunk of reading but he had me second guessing myself.
