(MAF +#'s) (LTFT -#'s)

So all last year I got all my part throttle and some wot tuning done but when summer hit the tune was way off even though it was the same temp. Well now my MAF table in scanning is always showing positive numbers so I copy paste onto tune by .5% and then my LTFT start going negative. I thought I was trying to get my LTFT to 0 and I was doing this by MAF tuning but it seems to not be working. Is my wb going on me or what. I'm also getting huge kr but afr is good but not my LTFT.

Scan: http://www.box.net/shared/ru3dtpc40l

Tune: http://www.box.net/shared/3r8adgr886


Mods on l36 camaro: zzp xp cam, 105 valve springs, gtp fuel injectors, intake, headers and full 2.25 true duals.There are more but these are the main ones.

When was the last time that you ran a free-air calibration of the O2 sensor on your wideband?

Quote:

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Originally Posted by umrjmac

When was the last time that you ran a free-air calibration of the O2 sensor on your wideband?

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When I first installed it. It is a lm-1, so when and how often should I perform a free-air calibration because I only press the calibration button when I first installed it.

From the manual for your Wideband kit
http://www.innovatemotorsports.com/s...LM1_Manual.pdf

5.3. Calibration Schedule
Normally aspirated daily driver:
- Calibrate before installation of new sensor
- Calibrate new sensor again after 3 month of use
- Thereafter calibrate once a year or every 20,000 miles, whichever comes first
Turbo car, daily driver (tuned rich):
- Calibrate before installation of new sensor
- Calibrate new sensor again after 3 month of use
- Thereafter calibrate twice a year or every 10,000 miles, whichever comes first
Race car
- Calibrate before first installation of new sensor
- Calibrate once per race weekend
Dyno use
- Calibrate a new sensor
- Calibrate every 2-3 days, depending on usage

thank you

I am getting some -1's on my MAf(afr error) but still getting -7 to -13 on my LTFT I am even resetting fuel trims after every recalibration of the maf. I then drive for a day then start scanning so Im not sure what is going on. My STFT are every close to 0 though if that helps at all. I'm going to see if what Im recording is what the WB is really reading, I just have to get a computer that wont die in 10sec out to the car. so could this be anything else besides my wb not recording right. I thought when you dial the maf the LTFT will become 0 just like the afr error. Is there a different process to dial the ltft to 0.


EDIT: well i have been reading and sometimes the car will run of the ve table but only if the maf fails or if the maf cant keep up (not the right term). So if I VE tune will my fuel trims start to zero out.

Quote:

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Originally Posted by Gotchocmilk39

I am getting some -1's on my MAf(afr error) but still getting -7 to -13 on my LTFT I am even resetting fuel trims after every recalibration of the maf. I then drive for a day then start scanning so Im not sure what is going on. My STFT are every close to 0 though if that helps at all. I'm going to see if what Im recording is what the WB is really reading, I just have to get a computer that wont die in 10sec out to the car. so could this be anything else besides my wb not recording right. I thought when you dial the maf the LTFT will become 0 just like the afr error. Is there a different process to dial the ltft to 0.


EDIT: well i have been reading and sometimes the car will run of the ve table but only if the maf fails or if the maf cant keep up (not the right term). So if I VE tune will my fuel trims start to zero out.

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If your LTFT/STFT values arent close to 0 (+/- 3 or 5), then the tune is off. Tuning your VE and/or MAF is what it will take to get it to even out. I would start by idle/cruise tuning using your STFT values (disable LTFTs).

As long as you are driving in closed loop, your wideband should be showing close to 0% error if its calibrated correctly since the car uses the fuel trims to get the AFR to stoich. If you stomp on it, that's another story.

Quote:

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Originally Posted by umrjmac

If your LTFT/STFT values arent close to 0 (+/- 3 or 5), then the tune is off. Tuning your VE and/or MAF is what it will take to get it to even out. I would start by idle/cruise tuning using your STFT values (disable LTFTs).

As long as you are driving in closed loop, your wideband should be showing close to 0% error if its calibrated correctly since the car uses the fuel trims to get the AFR to stoich. If you stomp on it, that's another story.

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Thats the thing my config say that I have little to no afr error but the car is having way negative LTFT's. Am i getting a good afr because the car is compensatinng for the richness with the LTFT or should I be getting negative numbers in my AFR error because I have negative numbers in my LTFT.

Here is a current tune and scan from today.

Tune
http://www.box.net/shared/978emrpdo6

Scan
http://www.box.net/shared/z1m13hs6i6

Quote:

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Originally Posted by Gotchocmilk39

Thats the thing my config say that I have little to no afr error but the car is having way negative LTFT's. Am i getting a good afr because the car is compensatinng for the richness with the LTFT or should I be getting negative numbers in my AFR error because I have negative numbers in my LTFT.

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As long as you are in closed loop (using STFTs and LTFTs), your AFR%Err should be near 0. The fuel trims will vary in order to get the resultant AFR mix to be stoich, which is what your wideband reads.

Quote:

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Originally Posted by umrjmac

As long as you are in closed loop (using STFTs and LTFTs), your AFR%Err should be near 0. The fuel trims will vary in order to get the resultant AFR mix to be stoich, which is what your wideband reads.

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So what your saying is that by me maf tuning in closed loop I am getting my correct afr but the car is helping to do it. If i Maf in open loop and get my afr with out the LTFT and STFT help then when I go back to closed loop with the LTFT and STFT they should be close to zero.

correct :)

open loop tune maf and ve, then when you go back to closed loop your fuel trims should be close to 0. (be sure to reset your fuel trims in the scanner after you configure it to run open loop)

you can also do idle/cruise tuning in closed loop by turning off the LTFTs (reset the fuel trims in the scanner) and then logging STFTs. Same process. You would still need to do the open loop tuning for non-idle/cruise.

Got a 150 amp converter at best buy for 17 dollars because it was opened normally 54 woot now I can start open loop tuning. Thanks Umrjmac for all your help.

any time. keep us posted on your progress:cheers:

I cant seem to get my Command AFR to sit at 14.7 in open loop, when i go back to close loop it sits right at 14.7 but in open loop it bounces between 14.9-15.2 what is going on. Following russ's Open loop MAF tuning guild (Sticky) but im not unpluging the O2 sensor I'm just setting the closed loop table to a really high temperature value so it doesn't come on.

Edit: so is my car not going into PE mode? even though I though I followed the steps in the open loop tuning guild


EDIT; fixed just a little throttle and the command afr went p to 14.7 and stayed there just had to hit the space bar to get rid of the old data then start back up scanning and it stayed there at 14.7 but I have to do it everytime other wise it jumps around. Is there a way to filter out decel on the afr error because when im at idle I am at 4% throttle is this normal?

well idle and part throttle MAF and VE tunes are done (7500 on the MAF and 4K rpms on the VE) . I drove the car today and will drive it alittle tomorrow and scan in close loop to see how everything is going, then I will move on to wot MAF and more throttle to the VE.