Quote:
Originally Posted by tomm.brz
of course ltft in open loop is thought as a band aid for a tune that is identical for every car out there in the world
Tuners don't think like OEM in some things, quite the opposite because oem need to respect emissions somehow and accept a lot of compromise
Tuners go for precision and each car needs different settings, while 1 single tune of OEM must work in millions of cars potentially
LTFT is anyway kept enabled in closed loop (low mid loads ) all the time as it is helpfull and can help diagnosis in case of problems ( that s the value that triggers the CELs for too lean or too rich)
and in open loop it just tries to compensate whatever condition is affecting the AFR
If it calculates that the fuel trims in closed loop are now averaging in whatever direction, it applies an LTFT in open loop too
but it just hopes to have done a positive thing, it doesn t know the result because it doesn't check, it is in fact an open loop
>2017 cars have closed loop also at WOT untill 6400rpm so they are leaner and less erratic
having closed loop at WOT can be dangerous as if the sensor gets fucked up and start to command lean afr at WOT at high rpm, engine can explode, if no failsafe is taken in account against this
but usually if afr gets so lean , exhaust temperature will raise and the ecu then triggers the closed-looping off and put a rich commanded afr in open loop
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Since LTFT can be disabled in open loop, does that mean that we can now rescale the MAF at the higher LTFT bands which impacts the LTFT in OL previously?
I find that my current scaling at that band in CL is about -3.5% which certainly can be improved, but I cannot make changes to it as it will affect my final LTFT in OL which makes it deviate further from 0%.
@
Open Loop my guess is that your IAM at that time was lower than your friend's at that time during the first run, seeing that you are down on power across the entire band. Same fuel used as well?