SophieSleeps

iTrader: (19)

Credit goes to l2r99gst for fingering this out. I really don't know a ton about this, so hopefully other people can chime in for questions.


This is a step-by-step of how to change the scaling for your MAF.
This doesn't affect your map. It affects the way ecuflash reads your map and how you interpret it. Once you change this, it will apply to all maps that you load with ecuflash.


Step 1: Load up ecuflash and right click on MAF scaling. Select "edit map"


Step 2: Here is what the finished table should look like. Circled in red are the important things. Click on the "Scalings..." button to add your custom scale.


Step 3: Click on the "add" button to create a new custom scale


Step 4: Here is a pic of what comes up. This is the screen that you will edit to make your new scale.


Step 5: Enter in the values that I've circled in red. Click "ok"


Step 6: Now you're back at the "edit table" screen. Make sure that the Y axis load scaling points to the scale that you just created. Use the dropdown menu to select it.


Finished: Your old scale and your new scale. Old one begins with 192. New one begins with 19.




Here is an example of how you actually put it into action.

Step 1: First you need to datalog your short term and long term fuel trims at a given MAF reading. This tells you how far "off" you are. So if your trims are +10%, that means you need to scale the MAF by 10%. The reading can be in Hz, lb/min, L/min, L/sec etc. Ultimately we want to end up reading MAF in Hz because that is what we just scaled ecuflash to. I've included a chart which can get you a rough idea of how to convert to Hz.

Here is a shot of what I logged with my OBDII scanner. Notice the long term fuel trim, short term fuel trim, and I have my choice of reading my MAF in lb/min or g/s. My OBDII scanner gives both these values. Yours might give a different one.


Here is a nice chart provided by l2r99gst that will help you convert whatever unit you are reading MAF to Hz used by ecuflash. For the example, you can see that with my OBDII log above, that I will use either lb/min or g/s to find the corresponding Hz value that ecuflash uses.




So...here is how you find out just how "off" you really are.
You add your long term trim and your short term trim together for any given MAF value. Here you see 12.5 + 10.9 when my MAF reads 0.327lb/min




I need to find out where my 0.327lb/min falls on the ecuflash map so I look at this chart. I find my lb/min value. It's very close to the one given on the chart. I look over to my right to see what value ecuflash has associated with that row. It's 18.75 (actually 19 because ecuflash rounded up)
Another example: If I were datalogging and found my MAF value to be 4.00 lb/min I would look at this chart and know that I would need to adjust the 200 Hz value in ecuflash.






So now that I know i'm working with the 19 cell...here is how I actually calculate the changes that I need to make in order to scale.

My long term trim + my short term trim = 23%.
I need to add 23% to my MAF scale.
At the 19 cell, the factory value is 145.
There is an 'adder' value that is used so always add 140 to the factory value.
145+ 140 = 285.
I want to add 23% of 285.
285 * 0.23 = 65.55
145(my original value) + 65.55 = 210.55
210.55 is my new value.


Here it is changed in the MAF scaling map.

4WS Tuning

iTrader: (73)

judging by all the colored arrows i need to understand this and use it lol


but im not following..

can i have a quick explaination why i would need to do this

thanks!

SophieSleeps

iTrader: (19)

If you get an intake and pipe, it changes the amount of air going into the car. You may need to change the way your MAF reads air.

If it thinks it's getting a pint-size cup of air but actually is getting buckets of air...you will want to change that. The car uses fuel trims to adjust for things like this, but you can go outside the range of your trimming capability. The ultimate goal of this is to get your fuel trims a close to 0 as possible.

eficker

iTrader: (19)

Could this also be used for closed loop tuning, instead of altering the actual targets?

SophieSleeps

iTrader: (19)

It is only for closed loop tuning. It doesn't affect open loop.

All this changes is how much air the MAF sensor thinks is passing through it.

At idle, does it think that a little is passing through...or did you put on an intake and now a ton is passing through it. Well, if you put on an intake and significantly changed the airflow, you'll have to re-scale the MAF sensor so that it reads the correct amount of air.

Ultimate CC

iTrader: (122)

nice write up...

DeiPro

Sophie,

Did this correct you trims? can you post the results

Kyle

4WS Tuning

iTrader: (73)

hmm ill check it out... thanks!

SophieSleeps

iTrader: (19)

I am still trying to correct them. I started this last night.
I successfully changed the scale. That was easy.
My long term fuel trims are now at 0 so that is definately a start. Before they were pretty high.


Here is how I convert my lb/min to Hz.
I created a table in excel and did a "lookup" on that table.

l2r99gst

iTrader: (2)

This affects closed and open loop. This table is basically the calibration for your MAF and the stock intake setup (airbox, pipe, etc). The ECU uses it to translate a Hz value into a mass airflow so that an IPW can be calculated.

The reason you may want to change this table is because a modification like a cone filter or an intake pipe may alter the airflow past the sensor's measuring area, either bypassing more around it or passing more through it. You basically want to recalibrate the setup so that you are getting an accurate airflow value.


Eric

SophieSleeps

iTrader: (19)

Retarded. I knew that but just didn't make the connection.
I was thinking about tuning idle...but this is related to my question about re-scaling the entire map with a given percentage...but whatever. I just rescaled the first few values so my open loop tuning wouldn't be affected. I have my AFR's perfect and don't want to f with it.

dubbleugly01

iTrader: (24)

my stock 03 maf scaling looks quite a bit different than yours (Evo IX) sophiesleeps. I start at 182 and to 291. If I could figure out how to do a screen shot, I'd post it here, but damnit...... I haven't figured out how to do it.

Regardless, I used your formula to rescale the lower Hz cells to clear up some light load issues I'm having, and yes, it does have a definite impact on a/f's and driveability. I started out using a small step change, only 1/2 of what your formula recommended, if I used the full amount of correction, it was just to big of a step change for me to be comfortable with. Either way, the 1/2 adjustment had a noticeable impact, in the right direction. I plan on playing with it more tomorrow.

Thanks for posting this tutorial.

SophieSleeps

iTrader: (19)

There's nothing wrong with caution.
I did the same thing.

Then I just laid my ***** on the floor and went with my "formula" if you want to call it that.

Credit shouldn't go to me. It should go to the dude who fingered this stuff out. I can never remember his SN.

dubbleugly01

iTrader: (24)

l2r99gst, thanks to you to! Unrforutnately for me, he speaks a different language, above my line of reasoning.

SophieSleeps

iTrader: (19)

That's why I created this thread. It was kind of hard for me to understand him so I tried to dumb it down so everyone else could just get it done.