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Step 1. Read through Steps 1 and 2 of the Helpfile thoroughly.
Step 2. Repeat Step 1.

You probably want to download the excel file below, so you can follow what I'm talking about. Ok, I'll assume you understand everything except how exactly to do perform the MAF g/s test and make the changes to your MAF tables (A & B). If you do not, please read the MAF Cal 101 to get a general overview here: http://forum.mazda6club.com/atr-engine-tuning/239808-maf-calibration-101-stfts-ltft-etc.html

So, the only thing you need to log is MAF g/s, MAF volts, and LTFTs. Start in 2nd @ 1,500 rpms (like 5 mph or so), and SLOWLY accelerate (Have your AP set to MAF g/s on the display) until you hit over 100 g/s. I usually do it up to 130 g/s or whatever until I run out of gear, but it doesn't really matter over 100 (that's the last breakpoint iirc). You may find it takes several tries to do this smoothly before "runing out of gear" lol. It's not that hard, but you'll see what I mean.

So, now you should see you're LTFT's following a "pattern"... As you look at how the MAF g/s increase on your datalaog, you''ll see different 'blocks' of fuel trims (color coded in excel file) across different MAF voltages (theres's 5 breakbpoints... re-read that section in the helpfile, it's Step 2). I attached an old MAF g/s test I did to calibrate my MAF in the past. This isn't a great one, but you should be able to follow and understand it.

The top part in yellow... my LTFT's are +2.18 for voltages between about 1.32 and 1.74 volts (we'll see a little 'problem' here, but that's good because it'll happen to you too.. we'll get to later).

Next is Orange.... LTFT's are +5.3 for voltages between about 1.55 and 2.17

Next is Light blue... LTFT's are +2.18 for voltages between about 2.24-2.37

Last = blue.. LTFT's are +1.4 from 2.4 volts to the end for the most part.
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So, in my case as all the numbers are positive, that means my car is ADDING that percent of fuel and those given MAF voltage ranges we just figured out by doing the MAF g/s test.
So, now you open the MAF table A, and highlight the cells that correspond to these, and adjust. For example:

The minor issue I was saying earlier was that "oh no! there's overlap!!" with the top yellow volts.. I wouldn't worry about this. Notice my foot wasn't on the gas at the beginning... Instead of using that FIRST +2.18 from 1.32-1.74, I would just use it to 1.54 volts. So open your MAF cal table A, and here's what you do:

1. Highlight MAF volts 1.33 through 1.55, Press the "M" key (mulitipler) and type in 1.02 (for the 2.18% you're adding). You can also click in cell for 1.33 volts and then shift click into the cell for the 1.55 volts, and it will select all the values in between. You can also copy and past like excel (and to and from excel) just FYI.

2. Highlight volts 1.56 to 2.17 volts (or whatever the closest one is), press "M" and enter 1.05 (for the 5% fuel it has been adding).

3. Hihghlight volts 2.24- 2.37, press "M" and enter 1.02

4. Volts 2.4 and up, press "M" and enter 1.01 (because we only need 1% more here)


Now, if some of your fuel trims are negative, you simply subtract the %LTFT from 100, and use that as your multiplier. That is, if your LTFT is -3% for a certain MAF voltage range, you simply highlight those cells as above, press "M" and enter 0.97 so it pulls 3% of fuel.

FINALLY, now that you have made all the changes to MAF table "A", simply copy and paste them into MAF table "B." To do this, click in the far left cell of MAF table A (0 volts), and then scroll all the way to the right side (5.0 volts or whatever) and hold SHIFT, and then click in the last cell on the right. That will highlight the whole area (works the same elsewhere in ATR). Now hit "CTRL + C" to copy the entire set of values, and then click in the MAF B table, click 0 volts, scroll all the way to the right, and shift-click the last cell as before to highlight the entire MAF B table, and hit "CTRL + V". That will past the values you copied from MAF table A into MAF table B. Check to make sure the values are the same before moving on (just to make sure you copied it right the first time). IIRC, I don't think the helpfile mentions some of these "short cuts."

I haven't done mine in while, but I'm kinda anal about it. I'll do like 4 MAF g/s tests and try to eliminate any "cross over"... different LTFT's in the same voltages from 2 separate logs, etc. I'm rusty as hell though! I calibrated my old map like 3 times, and I had all my LTFT's within 1.6! They were 0 just about everywhere, except one "breakpoint" but it was already so good, I didn't bother messing with it.

NOTE: This is NOT a substitution for the ATR Helpfile. Tuning is nothing to be taken lightly... there is a pretty steep learning curve, and you can easily blow your engine if you don't know what you're doing. Do not touch any tables in ATR unless you understand exactly what they do, and you are confident in your ability. Read through your Helpfile thoroughly, and ask questions. Tune at your own risk!!!
 

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Discussion Starter #2 (Edited)
Waiting for Speedtown to have an ATR break-through...
 

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you beautiful bastard I finally understand, I tried all yesterday to do this....FTL.


But now with windows seven and that crazy snap feature I can look at the damn excel file and this example and I understand!!!!!!! Good LTFT here I come, and then bring on the boost.
 
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Thanks for the write-up DF-
you covered the transition from grams to volts a bit more gracefully than the helpfile.

so nice to finally be able to talk with my car....
 

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Which is more accurate-
DF indicates above to only use LTFT for MAF calibration

ATR Help file indicates to combine both the LTFT and the STFT readings for MAF calibration



from the ATR help file:

After the vehicle has come to temperature, watch your MAF voltage and A/F trims. You want the combination of your A/F trims to be as close to 0 as possible. EX = If your STFT is +5% and LTFT is 0, then simply look up the MAF Voltage, which should be close to 1.2-1.28 volts at idle, on the MAF Calibration table and adjust the grams/sec value for that voltage up (+) until your combined fuel trims are 0 or close to zero. These adjustments can be made very easily by looking at the combined % correction of the STFT & LTFT. If that total is +6% then you can highlight the MAF Calibration cell for that particular MAF voltage and hit the “M” key, you will then be prompted to enter a floating point value. The correct value for this particular situation would be 1.06.

Asking because I have been unable to achieve respectable fuel trims with /just/ the LTFT #'s
 

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well if you don't give the map long enough to adjust and your stft are still fluctuating then you will probably have to make more calibrations after that. but if you take the stft into account then you'll be closer to your end result. you won't be able to get things to zero out because there are to many factors that will cause the trims to change daily.

so the best thing would be to get your ltft to a point where you don't see them changing much and then just make your changes off of that and forget the stft.
 

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K-

so, for knee-jerk first fix when things are way, way whacked out, use both. Then let it settle for 50(ish) miles & see how the LTFT's balance themselves out and fine tune using just the LTFT numbers.


I mention the knee-jerk reaction part since I'm pulling +10 LTFT numbers from what is supposed to be the exact map for my mods- test pipe & Cobb SRI, so I'm starting with stage1+SF v1.06.

Just to be safe I returned to stock, and my numbers settled back to pre-AP LTFT numbers ranging from 0 to +2.


Target range for No. Florida temps & such is to be within 3. This time of year I can drive to work with temps in the 30's, be in the 70's at lunch, and back to the 40's driving home. For my dirt bike I ended up with summer and winter jetting, and suspect I'll do the same here with "hot" & "cold" maps...
 

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you might want to try and calibrate it to the mid temp range. like i was calibrating mine when it was 30 degrees out so if it was adding +5% i would only calibrate +3% just because I know when it warms up it will start to go the other way.
 

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Discussion Starter #10

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Hey no problem man, you're welcome!
 

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Just wondering, i cant get my volts to go down to 1.32 like yours. My lowest was 1.41, is this just because i have an intake? ATR says something about an intake scaler? Also my break points seem to be off from yours, just wondering if this is also because of the intake?

Or is this all because your modding a stock tune and im modding AP stage 1+SF MAP?

My log is below, i use open office hope it will still open.
 

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