can someone explain some stuff about fuel trims to me please
04-27-2004, 08:23 AM
#1
can someone explain some stuff about fuel trims to me please ok im sort of confused here. i had my 02's running like 925 mv and now my LTFT's are -3.91% and now they are down to about 895 or so. if i get the fuel trims adjusted to about -1.56% does that mean ill see my WOT fuel numbers increase? i have to tunr right for part throttle and hten do th eWOT because the fuel trims will add or subtract that percentage from part throttle it remembers at WOT right?
04-27-2004, 09:37 AM
#3
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As long as you are negative (0 to -10 the close r to 0 the better) at part throttle and they lock at 0 when you hit WOT then you can move on to tune for WOT.
It will only ADD at WOT IF your PT Fuel trims are positive
i have to tunr right for part throttle and hten do th eWOT because the fuel trims will add or subtract that percentage from part throttle it remembers at WOT right?
04-27-2004, 11:05 AM
#4
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Over several "highway pulls" I observed my WOT
O2s ranging from 935 to 885mV, within minutes
of each other, same RPM/TPS etc. That's all just
about thermals in my view, and the reason you
can't get more than ballpark-right using the stock
sensors. The output when hot is well different from
fresh-off-cruise.
Changing PE will change the "center" of the "cloud"
but determining whether you really need to move
it, should probably come from either some quantitative
performance measurement or from a wideband reading.
O2s ranging from 935 to 885mV, within minutes
of each other, same RPM/TPS etc. That's all just
about thermals in my view, and the reason you
can't get more than ballpark-right using the stock
sensors. The output when hot is well different from
fresh-off-cruise.
Changing PE will change the "center" of the "cloud"
but determining whether you really need to move
it, should probably come from either some quantitative
performance measurement or from a wideband reading.
04-27-2004, 10:19 PM
#5
yeha i know i need to use a wideband, but im tryin to just figure it out so it will be ok with no detonation on the road until i dyno. by no means am i using the stock o2s to try and tune my car perfect lol. but they do stay consistent when i make some runs.
