Long term fuel trim's
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Joined: Oct 2002
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From: mcallen, texas, usa
Long term fuel trim's I have a 2000 5.3 silverado with many mods. I started to log my ltft (bank1, bank2) and averaged them out. I get an average of 12 on bank1 and 10 on bank2. I edited my maf and it does not seem to change. Then i edited my IFR and nothing seemed to change either. Am i doing something wrong??
Thank You.
Thank You.
Thread Starter
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Joined: Oct 2002
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From: mcallen, texas, usa
Originally Posted by davidmtz
I have a 2000 5.3 silverado with many mods. I started to log my ltft (bank1, bank2) and averaged them out. I get an average of 12 on bank1 and 10 on bank2. I edited my maf and it does not seem to change. Then i edited my IFR and nothing seemed to change either. Am i doing something wrong??
Thank You.
Thank You.
I don't think there is a way to affect change in fueling from bank to bank. My car always shows a +2% difference from B1 to B2. I think it has to do with the output of the O2 sensors.
I don't recommend changing the MAF calibration unless you have changed the MAF. The injector flow table will have a direct effect on the fuel system only. The MAF table will affect other functions such as timing and trans shifting.
Hope this helps.
Richard
I don't recommend changing the MAF calibration unless you have changed the MAF. The injector flow table will have a direct effect on the fuel system only. The MAF table will affect other functions such as timing and trans shifting.
Hope this helps.
Richard
Many vehicles seem to have a bank-bank LTFT
imbalance. Especially at idle, which is probably where you see the highest LTFTs (MAF is inaccurate, injectors
have actuation delays that show up at narrow pulse
width, side-side pressure differences throught the fuel
plumbing, etc.).
I would pay more attention to your non-idle LTFTs. You
might even want to forget the idle cell in your averaging.
My LTFTs are lower, the higher flow & RPM get.
MAF and IFR tables are whole-engine params and I
don't think they have any separate bank tables. If you
found separate fuel tables for Bank 1 and Bank 2, then
you could adjust separately. But in any case I think
you'd just be chasing a non-critical difference.
imbalance. Especially at idle, which is probably where you see the highest LTFTs (MAF is inaccurate, injectors
have actuation delays that show up at narrow pulse
width, side-side pressure differences throught the fuel
plumbing, etc.).
I would pay more attention to your non-idle LTFTs. You
might even want to forget the idle cell in your averaging.
My LTFTs are lower, the higher flow & RPM get.
MAF and IFR tables are whole-engine params and I
don't think they have any separate bank tables. If you
found separate fuel tables for Bank 1 and Bank 2, then
you could adjust separately. But in any case I think
you'd just be chasing a non-critical difference.
Thread Starter
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Joined: Oct 2002
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From: mcallen, texas, usa
Originally Posted by WS6FirebirdTA00
what mods do u have? when i changed my lid and MAF sensor i was at about 11% and just got predator to tune it for me now they both read dead on 0%
Am i doing what i am supposed to be doing? I logged my LTFT 1&2 for a 20 minute drive at different speeds and then average out my ltft's and come up with a 10 & 12 on the banks. Now those numbers are the ones i need to take down to zero or negative 2 to 8 right?
u really wanna keep it at about 0 to -2 um.....i get best results crusing down the interstate at about 70 mph at steady throttle for about 2 miles and then i read the numbers. how did u get the numbers?i woldnt imagine it woudl be that far off, and i would think the headers would help it richen up a little more
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Make sure you are data logging for at least 20 minutes for each change. Go for a nice drive with a lot of hwy cruising speed and some normal stop and go conditions. The longer you datalog the better.
And, like what was stated above, do not mess with the MAF table unless the MAF is altered some how(ported, aftermarket). Use the IFR table to bring your trims into your target area. One more useful tip, use your stock MAF sensor(if you changed it out for something else) for your baseline tuning then you can change the MAF out if you want. The trick is to have only one variable or change at a time...trust me because I am fight this issue right now myself.
Good luck,
Josh
And, like what was stated above, do not mess with the MAF table unless the MAF is altered some how(ported, aftermarket). Use the IFR table to bring your trims into your target area. One more useful tip, use your stock MAF sensor(if you changed it out for something else) for your baseline tuning then you can change the MAF out if you want. The trick is to have only one variable or change at a time...trust me because I am fight this issue right now myself.
Good luck,
Josh
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TECH Addict
Joined: Jul 2002
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Originally Posted by davidmtz
So if my ltrims are positive and i have ls1edit v1.31 i would multiply the IFR TABLE BY 90% and start logging again?
joel
