HOW TO CALIBRATE YOUR MAF! With An Example

[dougefresh_]

EDIT: Excel file re-attached.

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 don't, see post #49 on p. 2 where I break it down a bit. 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 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 wre 0 just about everywhere, except one "breakpoint" but it was already so good, I didn't want to mess with it.

I hope you find this helpful. I wanted to add a discussion of fuel trims, what they are and what they mean, but I haven't had a chance. EDIT: Brief overview of the MAF, Fuel Trims, and the MAF calibration is in post #49 on page 2.

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PART 2: Calibrating Your WOT afrs.
***Be sure to do step 1 above first and make sure you understand it***. Now read Step 4 of the Helpfile, which is right here, verbatim:

4th – Establish proper safe fuel curves. Please make sure that the Weighted Interpolation box has been checked. This setting is found in the Display tab of the Configure Options menu, which can be accessed in the software by pressing CTRL+F key. The fuel targets at idle and at light throttle will and should always be 1 Lambda (or 14.68 AFR with petrol), for this is a Closed Loop (CL) fueling target. When you increase your engine load from idle or part throttle you should always see a smooth transition from 1 Lambda (14.68 AFR) to your Open Loop (OL) fuel targets. These dictated fuel targets are in the Fuel OL/WOT Commanded EQ (No Knock) table. If steps 1, 2, and 3 have been properly performed then you should not need to modify much of your part throttle fuel targets because the transition will always go from ~1 Lambda down to the desired Lambda or AFR for WOT. This transition will only happen after any closed-loop delays have taken place. Fuel OL/WOT Commanded EQ (No Knock) calibration. We suggest you start off with excess fuel and run the engine richer than you want for your final tune, something around 0.68 Lambda (lower 10.X:1 AFR Petrol). Leaning the engine out from a richer fuel curve is a much safer approach to tuning your fuel curve. Once all of the above tables have been calibrated, you will want to datalog your AFR Actual and compare it to your dictated Lambda (AFR) in your Fuel OL/WOT Commanded EQ (No Knock) table; you can make your adjustments to your MAF Calibration from there. We highly advise that you start your WOT pulls by focusing on the mid RPM ranges then working your way up to just before redline. EX: Start your pulls on the dyno from 3200 RPM and go to 4200 RPM. Check the values dictated in your Fuel OL/WOT Commanded EQ (No Knock) table against the Actual AFR as measured in the exhaust stream. This comparison only relates if you have an intake system that is other than stock; if your dictated A/F is 11.0 and you measure 12.0 in the exhaust stream, then you will want to add (+) grams/sec for the MAF voltage that corresponds for that RPM and load point. The specific adjustment for the above situation should be multiplying the corresponding MAF flow grams/sec by 1.0909 = 12/11. You should be measuring very close to the same Lambda (A/F Ratio) in your exhaust stream that you have dictated in your Fuel OL/WOT Commanded EQ (No Knock) table. Your trim values will always adjust back and forth (+/-); let them, that is what they are supposed to do. You should not have to modify the MAF Calibration table if you have a stock vehicle. We highly suggest you do not spend excessive time tuning your MAF Calibration table just so the A/F output matches exactly what is dictated in the Primary Fuel table. You will chase your tail getting it spot on…then you will fill up at a different gas station that will have a different quality fuel and the targets may be slightly off. For the next pulls you can go from 3200 RPM to 5200 RPM, then 3200 RPM to 6200 RPM, until you can safely make pulls from 3200 RPM to just before redline. Again verify that what you measure with the Actual AFR matches what you have in the Fuel Table WOT. NOTE: IF ANY REPORTS OF KNOCK RETARD (KR) ARE PRESENT DURING THE PULL, THE ECU WILL INJECT ADDITIONAL FUEL TO HELP PREVENT REPORTS OF KR. The higher the reports of KR, the more fuel (in addition to the fuel dictated in the Fuel OL/WOT Commanded EQ (No Knock) table) the ECU will inject. In order to verify the MAF Calibration is set up properly, you will need to make sure that KR is not reported for the entire pull. This may require that you run a lower than desired boost levels in order to datalog a clean dyno run that has no reports of KR. If you notice that the ECU's closed-loop delays are longer than desired, then you can modify the various Closed Loop tables. Please use caution when doing so for this will change when and how the car transitions from closed-loop to open-loop operations which can greatly affect driving quality. What all of the above 4th step means to you: - Please be sure to verify that your fueling capacity is capable of keeping up with fueling demand. If you see your DI Fuel Pressure drop below 1200psi while at WOT, then we highly suggest you upgrade your CDFP. The stock CDFP usually hold DI Fuel Pressure at ~1500-1600psi, most high-flow CDFP usually hold DI Fuel Pressure at 1600-1800psi while at WOT. - Some DISI ECUs switches logic and blend fueling strategies in different modes. Fueling can go from stratified to homogeneous, and back. Torque targeting can go from boost targeting to load targeting. Closed-Loop (CL) to Open-Loop (OL) transitions may not be smooth on a vehicle where the turbo spools very quickly. - Fueling strategies change with reports of Knock Retard. For each 1 count of KR, you will see the ECU adds a proportion of fuel.

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I was running a bit rich (wot afrs around 11.3 with a commanded afr of 11.7), so I had to adjust my maf. I had also previously added 3% fuel to the upper portion of my maf cal when I went BT just to be safe. Now, just to be clear there are two ways to pull fuel if your wot afrs are rich (lower # than your commanded afrs in your OL/WOT No Knock Table A). The WRONG way would be to pull fuel from your ol/wot no knock a fuel table. Don't do that. The correct way is under Cobb's step 4 of the Helpfile which is "establishing proper, safe fuel curves," copied and pasted above in quotes. All you need to do is compare your actual afrs to commanded, and apply the correction as follows:

Actual Afrs/Commanded AFRs and take that decimal and apply it to corresponding maf volts.

I attached the two logs in one additional excel file named "How to Cal Wot AFRs Meth" I used to do this for people to see. I know you need clean pulls with no kr but there's barely any kr in the first log (1st sheet), and the afrs were consistent to what I have seen previously with no kr, so my ecu wasn't dumping a lot of fuel. Plus my command afrs are only 11.7 to begin with, which is very conservative while running meth (50/50 mix).

Note I just added a column for my commanded wot afrs of 11.7 (from 2.5K to redline) and dragged it all the way down. I then added another column called MAF ADJ as seen in thte log (for Maf Adjustment), and entered in a simple formula that divided my Acutal AFRs (AFRs column) by my Commanded values of 11.7 (OL/WOT NO Knock A), and dragged that formula down. And viola, I have all the correction factors I need in that column. Now I just looked at the corresponding voltages, pressed the "M" key and entered in the corresponding decimal.

Now, if you were lean instead of rich, you will end up with decimals greater than one, which means you are getting more air in, and by using the multitplier "M" key and multiplying but a number > 1 that will let the ecu know there's more air coming in (which is why you were a bit lean), and it will add more fuel, and you should be good to go. It's just the opposite of my example here as I was running a bit rich.

MAKE SURE BOTH YOUR LTFTs and STFTs are -.16 and you are in open loop when you got wot before you start adding fuel. You'll be adding fuel to the wrong table, which you shouldn't be doing anyways if that's the case. That is a discussion for other threads so search and you'll find some good ones.

Also, pay no attention to where I blocked certain things off.. it was just so I could keep easier track of what volts I was adjusting as I moved up the maf calibration in ATR. Finally, don't forget to copy and paste Maf Table A into Table B when you're done. GL

[flyrevs2]

gonna do this today, thank-you for the write up !!!

[xcoldricex]

will this work for calibrating larger maf housings?

[dougefresh_]

Originally Posted by flyrevs2 gonna do this today, thank-you for the write up !!!

You're welcome man, I'm glad that helped. After you've done it once, it's really easy (and quick) to do. Just make sure your map is broken in well before you do a maf cal.

Originally Posted by xcoldricex will this work for calibrating larger maf housings?

I don't see how you could calibrate the maf any other way, regardless of maf size. SS Installer said that he's never seen a MAF that didn't have 0-5volts (same as ours), so I think it should be NP. I'd double check w/ someone who is running a larger MAF just to double check, but I'm pretty sure it's the same. I have no experience w/ the larger maf, so I'm not 100% on this.

[djuosnteisn]

You calibrate it the exact same way for a big maf (maf is the same, just diameter of the tube is bigger).

But first you have to get the maf curve close enough for the car to idle and run.


You do this buy calculating the % increase in AREA of the stock tube to the bigger tube. Here's a quick example (i'm not 100% sure what stock intake size is, cause it's been so long. So i'll use 2.75" for this example):

Area of 2.75" intake = pi * r ^ 2 = 23.75
Area of 3.25" intake = pi * r ^ 2 = 33.16

That's an increase of 33.16 / 23.75 = 39%

So you'd want to do an initial maf scaling of 1.39 just to get your car running. Then follow the normal maf cal procedure.

[dougefresh_]

^Hey thanks DJ. I was going to say to ask you, but I wasn't sure if you had a larger maf or not. I haven't been on here too much lately. I just noticed your sig, and was like wtf? So now I"m gonna venture to the dyno section

[djuosnteisn]

Okay, had a quick sec to look, and I think stock MAF size is 2.62" (66.5mm), so the correct calculation for going to a 3.25" intake is this:

Area of stock: pi * (2.62 ^ 2) = 21.55
Area of 3.25": pi * (3.25 ^ 2) = 33.17

% increase = 33.17 / 21.55 = 1.54

So you need to multiply MAF curve by 1.54 to get the car running in first place for 3.25" intake

[xcoldricex]

sweet i think i'll try this on the weekend. thanks dustin!

[Ziggo]

Am I doing something wrong here? I have about 200mi on this flash, but I am not seeing the break points in the LTFT. I was planning on doing the LTFT+STFT thing anyway, but seeing the LTFTs flatlined like they are concerns me. I know in theory they could be the same across the rev range, but that doesnt seem very probable. Makes me think the ECU just hasnt been learning.

Maf cal run 1:


maf cal run 2:

[fjames]

Originally Posted by Ziggo Am I doing something wrong here? I have about 200mi on this flash, but I am not seeing the break points in the LTFT. I was planning on doing the LTFT+STFT thing anyway, but seeing the LTFTs flatlined like they are concerns me. I know in theory they could be the same across the rev range, but that doesnt seem very probable. Makes me think the ECU just hasnt been learning.

There are 5 LTFT ranges, which means 4 break points. You don't seem to have idle (R1) on your chart, so you have 4 ranges charted, which means a total of 3 break points possible and you're showing two of them.

I use the DH exclusively to do MAF cal, because it's so easy that way, and I can tell you that on my car, on a fresh map, R4 and R5 are often the same, so you look fine.

All you have to do to cal your MAF with the DH is set up a screen with g/s and LTFT and just monitor them. If you know the break points (write them down if you can't remember) you just play it around them to see what it's doing and adjust accordingly.

[hnda etr]

What would I need to do for a bored out (maxbore) throttle body?

[hnda etr]

FYI - when I was doing my MAF calibration, I would log 3-4 runs, then combine all of them into 1 spreadsheet and sort by g/s and then MAF voltage, etc...

I did this to see how the data was trending... Lots of color coding lol

May not be the best way, or for everyone, but my LTFT's are 0 to -1.6 across the board.. I wanted my trims to be negative as opposed to positive... I figure it's better to be removing fuel than adding it... But I'm sure it's all the same...

Also, I didn't do the summing of the short and long term trims - just long term..

[dougefresh_]

Originally Posted by Ziggo Am I doing something wrong here? I have about 200mi on this flash, but I am not seeing the break points in the LTFT. I was planning on doing the LTFT+STFT thing anyway, but seeing the LTFTs flatlined like they are concerns me. I know in theory they could be the same across the rev range, but that doesnt seem very probable. Makes me think the ECU just hasnt been learning. Maf cal run 1:

If you look at your LTFT in light blue, you can see that they pretty constant throughout the MAF g/s range, but you can see a breakpoint clearly between 10.5 and about 13 seconds. I'm not sure what values the blue line is at, but I'm assuming the DH is using the yellow scale. If that's the case, then they look like they are only ~ +3.75, which is great.

However, what you are doing wrong is using your DH to do this. Use your AP, and just log what I said in the OP... LTFT, MAF g/s, and MAF Volts. Leave your AP display on MAF g/s so you can watch them slowly increase, and don't forget to record the log(s)! Just re-read the OP, and log w/ the AP and NOT the DH, and you'll be fine. You can actually covert DH logs into .csv files, but they come out sloppy. You must have an AP, otherwise you can't calibrate the MAF. Unless you are tuning with a standback, and I know nothing about them.

Try again with the AP, and it will be much easier, and make more sense. Check out the excel file attached to the OP, and that should help.

[dougefresh_]

Originally Posted by hnda etr FYI - when I was doing my MAF calibration, I would log 3-4 runs, then combine all of them into 1 spreadsheet and sort by g/s and then MAF voltage, etc... I did this to see how the data was trending... Lots of color coding lol May not be the best way, or for everyone, but my LTFT's are 0 to -1.6 across the board.. I wanted my trims to be negative as opposed to positive... I figure it's better to be removing fuel than adding it... But I'm sure it's all the same... Also, I didn't do the summing of the short and long term trims - just long term..

That is exactly what I do, color coding and all, lol. And before a serious of mechanical issues that have plagued me recently, I had all my LTFT's between 0 and +1.6, haha. After you flash a map, or otherwise reset the ECU, your STFT's will bounce around quite a bit, until they eventually settle. STFT's are converted into LTFT's every 20 seconds or so, iirc. It still takes ~50 miles for the ECU to learn the fuel trims properly, and allow the "right" LTFT's to settle in. So, in 'theory' your STFT's should go to zero, BUT they will still fluctuate (weather, baro, whatever), and this is normal as mentioned in the Helpfile. However, if after you've calibrated your MAF, and you know what your LTFT's are, if you see them getting whacky, you most likely have a mechanical problem... usually a leak that is letting metered air into or out of the system (or both). Another thing people should keep in mind is that regardless if you've calibrated your MAF, when you upgrade your fuel pump, it will throw your FT's off a bit, and you may need to recalibrate. Ditto for any changes in breather mods. You probably knew all that, but I plunked it in here anyways for others, lol.

Originally Posted by hnda etr What would I need to do for a bored out (maxbore) throttle body?

I wouldn't think it would matter as long as you are using the stock MAF housing. I think of it as just reducing airflow restriction like any other mod after the MAF. Like if you just had an intake, and you calibrated your MAF, and then you added a TIP. The TIP just made the system less restrictive, but you'll have to recalibrate your MAF. I have no experience w/ the bored out TB, so I'd run it by DJ.

[Ziggo]

Originally Posted by dougefresh_ If you look at your LTFT in light blue, you can see that they pretty constant throughout the MAF g/s range, but you can see a breakpoint clearly between 10.5 and about 13 seconds. I'm not sure what values the blue line is at, but I'm assuming the DH is using the yellow scale. If that's the case, then they look like they are only ~ +3.75, which is great. However, what you are doing wrong is using your DH to do this. Use your AP, and just log what I said in the OP... LTFT, MAF g/s, and MAF Volts. Leave your AP display on MAF g/s so you can watch them slowly increase, and don't forget to record the log(s)! Just re-read the OP, and log w/ the AP and NOT the DH, and you'll be fine. You can actually covert DH logs into .csv files, but they come out sloppy. You must have an AP, otherwise you can't calibrate the MAF. Unless you are tuning with a standback, and I know nothing about them. Try again with the AP, and it will be much easier, and make more sense. Check out the excel file attached to the OP, and that should help.

I was just using the DH because I am very familiar with its use. I will do some more with the AP and see. I will probably get better logs anyway with more practice doing these strange pulls. The Purple scale is the fuel trim scale.

[djuosnteisn]

Bored throttle body's can be tricky.

There is a throttle table IIRC, and you may need to massage some numbers in there. I've heard they hunt at idle sometimes.

I'd have to open up my copy of ATR later and see what tables are available, but you basically want to reduce the necessary drive current down low, and keep it the same up top... kinda like making it more steep.

Cause for the same degree of opening (angle), there will be significantly more airflow than with a smaller TB.

[dougefresh_]

Originally Posted by Ziggo I was just using the DH because I am very familiar with its use. I will do some more with the AP and see. I will probably get better logs anyway with more practice doing these strange pulls. The Purple scale is the fuel trim scale.

Oh okay. On your AP, just go to "monitor" and "set datalog list" and just select MAF g/s (may say 'mass air flow'), LTFT's, and MAF volts. Now, those are the only things that will be recorded when you log. Just remember to re-select all the other stuff you want to log after your done w/ the MAF cal, because the AP will save those settings. Then back out of there (it will ask if you want to 'save' those settings... click OK), and then go back to monitor, and then datalog (NOT "live"... that doesn't record). Now, the AP is "ready" to log, so just press the middle button before you start, and you'll see it say "Logging." Press the center button again to stop the recording. You can log a bunch of other things at the same time, but you get a higher frequency (more data-points per second) with the less stuff that's recorded. I do it just so there isn't 15-20 columns of data coming into excel, and it makes things easier to see. Also, the AP starts logging MUCH faster than the DH, just FYI.

Originally Posted by djuosnteisn Bored throttle body's can be tricky. There is a throttle table IIRC, and you may need to massage some numbers in there. I've heard they hunt at idle sometimes. I'd have to open up my copy of ATR later and see what tables are available, but you basically want to reduce the necessary drive current down low, and keep it the same up top... kinda like making it more steep. Cause for the same degree of opening (angle), there will be significantly more airflow than with a smaller TB.

Thanks DJ... I'm sending all the curve balls I've never seen before you're way! lol

[djuosnteisn]

just no knuckle balls, hahaha.

And definitely no hairy balls.

[dougefresh_]

Originally Posted by djuosnteisn just no knuckle balls, hahaha. And definitely no hairy balls.

Haha. Smooth, shaven balls are okay then? lol


EDIT:

YouTube- Dave Chappelle - Balls

YouTube- Dave Chappelle - Balls

Did he ever come out w/ any new stuff since years ago?? I miss Chappelle... really funny dude!

[djuosnteisn]

lil boi ballz

[skeeter149]

ok i think i actually understand how to do this now and am gonna try it now.

[hnda etr]

Originally Posted by dougefresh_ That is exactly what I do, color coding and all, lol. And before a serious of mechanical issues that have plagued me recently, I had all my LTFT's between 0 and +1.6, haha. After you flash a map, or otherwise reset the ECU, your STFT's will bounce around quite a bit, until they eventually settle. STFT's are converted into LTFT's every 20 seconds or so, iirc. It still takes ~50 miles for the ECU to learn the fuel trims properly, and allow the "right" LTFT's to settle in. So, in 'theory' your STFT's should go to zero, BUT they will still fluctuate (weather, baro, whatever), and this is normal as mentioned in the Helpfile. However, if after you've calibrated your MAF, and you know what your LTFT's are, if you see them getting whacky, you most likely have a mechanical problem... usually a leak that is letting metered air into or out of the system (or both). Another thing people should keep in mind is that regardless if you've calibrated your MAF, when you upgrade your fuel pump, it will throw your FT's off a bit, and you may need to recalibrate. Ditto for any changes in breather mods. You probably knew all that, but I plunked it in here anyways for others, lol. I wouldn't think it would matter as long as you are using the stock MAF housing. I think of it as just reducing airflow restriction like any other mod after the MAF. Like if you just had an intake, and you calibrated your MAF, and then you added a TIP. The TIP just made the system less restrictive, but you'll have to recalibrate your MAF. I have no experience w/ the bored out TB, so I'd run it by DJ.

Originally Posted by djuosnteisn Bored throttle body's can be tricky. There is a throttle table IIRC, and you may need to massage some numbers in there. I've heard they hunt at idle sometimes. I'd have to open up my copy of ATR later and see what tables are available, but you basically want to reduce the necessary drive current down low, and keep it the same up top... kinda like making it more steep. Cause for the same degree of opening (angle), there will be significantly more airflow than with a smaller TB.

Awesome info guys, thanks!

[ms3brendan]

After all this time.. I finally did this. I haven't driven it yet but at idle, my LTFTs are at 0! Even when I rev! Great write up!

[801MS3]

Looking forward to doing my calibration..
Question.. I know you (doug) addressed this in another thread but.. Is there in sort of consistancy in what you need to do to your TRL after doing the calibration?
I had mine calibrated a few months back by a cobb employee (i had a different inlet and sri and stock tmic) And the fuel trims and afr were spot on, but the car felt much slower and the boost was lower.
Now i know the calibration effects your calc load, but other than just moving up the TRL slowly, is there any sort of percentage that it can be increased based off the amount of adjustment the calibration took?
I think i just confused myself..

[djuosnteisn]

Compare your previous MAF #'s in the voltage range you typically hit at WOT, with the new #'s.

If the new numbers are lower, your gonna hit higher boost.

If the new numbers are higher, you'll hit lower boost.

Adjust the TRL's by that same percentage, lower or higher accordingly.

[Ziggo]

Thanks for the help guys, I got it all figured out last night and reflashed this morning. Now I just have to get some miles on it and see if they settle down. (since I just installed a FMIC I am somewhat concerned about boost leaks)

I am looking to detune the car anyhow, so upping the MAF values around 10%
(they were all close to 10) should help with that too.

[801MS3]

Originally Posted by Ziggo Thanks for the help guys, I got it all figured out last night and reflashed this morning. Now I just have to get some miles on it and see if they settle down. (since I just installed a FMIC I am somewhat concerned about boost leaks) I am looking to detune the car anyhow, so upping the MAF values around 10% (they were all close to 10) should help with that too.

I just did an fmic install as well, and want to test for leaks before doing my calibration. I did the calibration log last night and my ltft's while doing that log are all over the place.. 13.2 2.9 7.9 8.4
Is that normal.. The 13.2 at the first break point is weirding me out.. Also when i am doing live monitoring of the ltft's it never goes above 8-9 but when i do the log it's showing 13.2?

[dougefresh_]

Originally Posted by 801MS3 I just did an fmic install as well, and want to test for leaks before doing my calibration. I did the calibration log last night and my ltft's while doing that log are all over the place.. 13.2 2.9 7.9 8.4 Is that normal.. The 13.2 at the first break point is weirding me out.. Also when i am doing live monitoring of the ltft's it never goes above 8-9 but when i do the log it's showing 13.2?

Yeah those fuel trims are terrible. Calibrating the MAF is a quick, easy fix though. As for the numbers, I'd just go by what the data log actually shows... those are all pretty high positive values. Do you remember what your LTFT's were before the fmic? Test the system for leaks, and then do another MAF g/s test, and post up the log.

[dougefresh_]

Sticky icky icky

[ms3brendan]

Originally Posted by dougefresh_ Sticky icky icky

+1

This is the first thread on this that I found to be incredibly easy to understand rather than the ATR documentation. I never really thought to just read it off the car's breakpoints in the log instead of going off the documentation and using the MAF g/s breakpoints since those vary. After that realization this process was incredibly easy.

After I calibrated mine though the LTFTs got worse and I reflashed back to the OTS map and after 100 miles they've settled a bit. I'm sure I'll need to do it after today though, CPE DP is going on and I'll be fully bolted... Haha.

Pro-tune should probably be next..

[dougefresh_]

Sweet, I'm glad it helped. Why were your LTFT's worse after the calibration though? I need a mani & a catted DP to be fully bolted . I'm waiting for the Labonte Stage 2 meth kit, and I may just get a catted DP, and a pro-tune after that.

[ms3brendan]

Originally Posted by dougefresh_ Sweet, I'm glad it helped. Why were your LTFT's worse after the calibration though? I need a mani & a catted DP to be fully bolted . I'm waiting for the Labonte Stage 2 meth kit, and I may just get a catted DP, and a pro-tune after that.

I'm not sure.. I almost thought I did it backwards but I don't think I did.. My LTFTS were at 6.8 so I highlighted that voltage range and put in "1.06", that is correct.. right?

Yeah I guess I won't be technically fully bolted but semi-fully-bolted haha. I won't have the mani. I haven't considered meth yet since after the FMIC install it's pretty much taken care of any of the KR issues I was getting before and the only reason I'd get meth is to take care of any unwanted KR.

[dougefresh_]

Originally Posted by ms3brendan I'm not sure.. I almost thought I did it backwards but I don't think I did.. My LTFTS were at 6.8 so I highlighted that voltage range and put in "1.06", that is correct.. right? Yeah I guess I won't be technically fully bolted but semi-fully-bolted haha. I won't have the mani. I haven't considered meth yet since after the FMIC install it's pretty much taken care of any of the KR issues I was getting before and the only reason I'd get meth is to take care of any unwanted KR.

Yes, for a +6.8 LTFT, the "1.06" (or 1.07) is correct. Only if the LTFT is negative do you subtract from 100. e.g. if the LTFT was -5.0, you'd hit "M" and then enter .95. It takes a few tries w/ the MAF g/s test to get the hang of the maf cal, but once you do, it's easy.

Yeah, I don't have much KR at all, but I was planning on running pretty high boost, so I can't really afford any KR! We'll see how it goes.

[hnda etr]

Originally Posted by dougefresh_ Yes, for a +6.8 LTFT, the "1.06" (or 1.07) is correct. Only if the LTFT is negative do you subtract from 100. e.g. if the LTFT was -5.0, you'd hit "M" and then enter .95. It takes a few tries w/ the MAF g/s test to get the hang of the maf cal, but once you do, it's easy. Yeah, I don't have much KR at all, but I was planning on running pretty high boost, so I can't really afford any KR! We'll see how it goes.

Have you, or anyone really, figured out what the actual VOLTAGE breakpoints are? Everyone that I see talking about the breakpoints, Cobb help included, refers to the breakpoints as an approximate g/s but I haven't seen anyone say, "breakpoint 1 is at 1.34 volts, breakpoint 2 is at 2.3 volts, etc..."

This of course, would differ between the 3's and 6's..

[dougefresh_]

Originally Posted by hnda etr Have you, or anyone really, figured out what the actual VOLTAGE breakpoints are? Everyone that I see talking about the breakpoints, Cobb help included, refers to the breakpoints as an approximate g/s but I haven't seen anyone say, "breakpoint 1 is at 1.34 volts, breakpoint 2 is at 2.3 volts, etc..." This of course, would differ between the 3's and 6's..

Good question, and I have no idea.... I never really thought of it, lol. I just calibrate my MAF and move on. DJ probably knows though. I'm too lazy to read the helpfile right now and take a crack at it, so I'll just defer you to him .

[jax ms3gt]

subing for when i get home..

[Snyeed]

Jayspeed3 posted this info in another calibrate your maf thread.

There are break points that the ecu uses for LTFT based on MAF AirFlow (g/s). Which is why when you slightly accelerate the LTFT's change.

Breakpoints (MS3):
0 ~ 5 g/s
5.01 ~ 16 g/s
16.01 ~ 28 g/s
28.01 ~ 77 g/s
77.01 ~ Full Range g/s

[hnda etr]

Originally Posted by Snyeed Jayspeed3 posted this info in another calibrate your maf thread. There are break points that the ecu uses for LTFT based on MAF AirFlow (g/s). Which is why when you slightly accelerate the LTFT's change. Breakpoints (MS3): 0 ~ 5 g/s 5.01 ~ 16 g/s 16.01 ~ 28 g/s 28.01 ~ 77 g/s 77.01 ~ Full Range g/s

Yes thanks, but we already know this...

I was looking for the VOLTAGE breakpoints...

[hnda etr]

Originally Posted by dougefresh_ Good question, and I have no idea.... I never really thought of it, lol. I just calibrate my MAF and move on. DJ probably knows though. I'm too lazy to read the helpfile right now and take a crack at it, so I'll just defer you to him .

Hopefully he does and chimes in!

[djuosnteisn]

I don't think there is a specific voltage breakpoints, because you could assign a g/s value to any voltage you wish. So as your scaling for a Big Maf for example... all of your g/s values are going to move left on the voltage axis... thus reducing their associated voltages.

And after you scale (IIRC), the break points remain the same... 0-5, 5-16, etc etc etc.


so the ecu doesn't concern itself with the voltage... only the assigned g/s.