MAF table mods to help BLM #'s ???

[BoostKillsStres]

Goal:
Get the BL table values that are at extreme ranges closer to 128.

Question:
If I have good idle bl #'s based on the injector constant but have other cells which are on the extreme high and low end, what is the correct method of maf table modifications for correcting this?

I have and understand the full maf table frequency vs. gps info and also the BL table boundries info for RPM vs. gps and am thinking the following:

Hypothesis:
If the BL # is low you need to find the gps range when you are in this cell and in learn mode then lower the maf table number for this frequency so less calculated fuel will be delivered thus the BL's should raise and be closer to 128.

If the BL # is high then conversly find that gps range when learning and raise the maf tables in that range so the calculated fuel increases for that range and the BL's should lower and closer to 128.

Questions / Comments:
Is this hypothesis correct? Am I going about this in the right fashion to get BL's which I have in the low 100's closer to 128 and my cell 15 which is in a 153-156 range closer to 128? By the way I do have a cell 15 lock patch in place but would like cell 15 closer to 128 so when chip swaps are done the car doesn't feel lean until in gets learned into the 150's.

TIA

 

[Eric Stage I]

You typed so much up there, I hate to let it go unanswered .

Your hypothesis is correct. There are many ways to tweak the chip around to get the blm's you want. Changing maf tables is one of them. There is no correct way. If it makes the engine run the way you want it to, then use it! Everyone has their own method.

I see you have a Translator. You can use that also to tweak your blm's around, because it effectively is changing your maf numbers also. In your case, without any "hard" code changes, I'd get your injector constant back down closer to the injector size so your higher end blm's come down (I assume you've probably got the constant up higher than #40 for those redstripes). Then adjust the maf tables in the lower airflow ranges to get the lower end blm's where you want. That's only me, you do it your way .

Let us know what you find.
Good luck,
Eric

 

[bruce]

Originally posted by BoostKillsStres

Forget about the cells.

There is no difficulty in finding the gms sec you need to change.

Read the article at GNTtype called Chip Tips or is it Hints, KenM just posted an article of mine that should help you out.

 

[2QUIK6]

Re: Re: MAF table mods to help BLM #'s ???

Originally posted by bruce
Read the article at GNTtype called Chip Tips or is it Hints, KenM just posted an article of mine that should help you out.

Bruce, maybe Tunercat has the tables labeled wrong as they have before with some of the Buick Turbo ECM def, but in TC it has tables 1-5 and they are labeled MAF vs. Counts1-5.
The tables themselves have units of "Counts" and "gm/sec".
What I'm confused about is where the "scalar" is you refer to and how to change it.
The first table for example goes from Counts 0-512 with gm/sec ranging from 3.0-8.25.
If I idle at 6 gm/sec MAF reading, and I'm lean, to richen it up, would I locate the "Counts" that currently contains the value closest to 6 gm/sec, and up it from 6 gm/sec to say something like 7 or 8 gm/sec?

 

[bruce]

Re: Re: Re: MAF table mods to help BLM #'s ???

Originally posted by 2QUIK6
Bruce, maybe Tunercat has the tables labeled wrong as they have before with some of the Buick Turbo ECM def, but in TC it has tables 1-5 and they are labeled MAF vs. Counts1-5.
The tables themselves have units of "Counts" and "gm/sec".
What I'm confused about is where the "scalar" is you refer to and how to change it.
The first table for example goes from Counts 0-512 with gm/sec ranging from 3.0-8.25.
If I idle at 6 gm/sec MAF reading, and I'm lean, to richen it up, would I locate the "Counts" that currently contains the value closest to 6 gm/sec, and up it from 6 gm/sec to say something like 7 or 8 gm/sec?

The Tunercat software in an effort to be user friendly has done the math for you. Down side is the entries are invisible.

Your easiest remedy is just getting some hex editing software, and then looking at the excel spreadsheet at GNTtype to do the math.

IF your setup isn't too far off from stock you just might be able to edit the tables as displayed in Tunercat. But, you can't do any of the trick stuff I mentioned in using 128s on table 3-4. But, I'm prejudged in how to work the tables.

Just rember which way your doing what.
And that's not as easy as it sounds.
Once you get your feet wet it starts making sense.

 

[BoostKillsStres]

My guess's from above are correct as after 2 chip changes my blm table is all around 128 +- 10 except for 2 cells which need a little more work.

I also have tunercat and its maf tables units are listed correctly but the gps appear to be off just slightly as you move up through the cells in each table. Example: On the low end of maf table 1, the difference is only about 0.4 and on the high end of maf table 1 its about 0.8. You can see these differences if you calculate the gps values as Bruce's article describes.

Tunercat doesn't have a table for the scalers so you'll have to change those w/ a hex editor. I only changed the table 3 scaler from 33 to 36 to allow a higher value in the 1024 cell.

If you have a lean idle, meaning your blm value is high, you need to raise the maf table 1 values so that at that idle count area you will cause the addition of more fuel. It just takes a little doing to see how things change and go from there.

My just off idle blm cells were the opposite, cells 2 and 3 were in the 102 and 101 range so I had to lower the values in the upper end of maf table 1 and in maf table 2 and 3 so there wouldn't be so much fuel added where the ecm had to pull it out where the blm's arrived at the 102 and 101 values.

Make perfect sense

My top row of blm's was:
136 123 102 101
now:
139 132 128 128 so I just need a tad more fuel at idle like you but there is a point at which you can get a little crazy. I'll probably find that point after a few more chips

HTH

 

[2QUIK6]

So maybe in my example I'm backwards...If the MAF is reading 6gm/sec and it is lean, I think I would need to "fake out" the ECM by changing the table so that 6gm/sec is in an entry with a higher "Count" number.
That way, 6gm/sec would add more fuel as the "Count" number that it is entered in is greater than it was before....does that make any sense.
In other words, will a gm/sec reading at a higher count # than it was before make it add more fuel?
*
Still kind of lost on the scalar thing.
Thanks

 

[BoostKillsStres]

"In other words, will a gm/sec reading at a higher count # than it was before make it add more fuel? "

Yes.
If you raise the gps values in any count level you'll be adding fuel. You have to remember the ecm is reading 'counts' from the maf and looking up the gps value you enter then calculating the fuel to command( I could be backwards here ).

I ended up raising gps values in higher count positions in order to lower blm's and lowered gps values to lower count positions in order to raise blm.
Hopefully that makes more sence.

 

[2QUIK6]

Ahh, Now I see, thanks Mark. I had it all screwed up trying to describe it, but what you said makes perfect sense....
So if MAF is sending the ECM say a "Count" of 128, which equates to an entry of say 6.2 gm/sec. If I change the gps at Count=128 to say 8.5, that will increase the fuel at 128 counts of the MAF reading.
I've got to do so more reasearch on the scalar value, if I get the address of them I'll notify Tunercat to add it. Guess I can play with the TC tdf editor and make the addresses editable.

 

[2QUIK6]

So now that I think about this. If I change the gm/sec entry at idle from 6 to 8, will I now see 8 gm/sec on the scan tool at idle if I used to see 6?
*
Where can I find info on how the Scalars work? I found them in the eprom layouts on gnttype and they are set to like 10, 18, 33, 86, 255, and 255 for MAF tables 1-6. What does this actual mean? (I notice each table happens to end at about the same gm/sec as the scalar is set to for that table)
Thanks

 

[2QUIK6]

Ok, I think I see where the scalar comes into play, from this link...
http://www.turbobuick.com/forums/showthread.php?s=&threadid=52885&highlight=scalar
*
Now, is it only used in determining the LV8 value?
And from the link, I see everything LV8 is used in...

 

[BoostKillsStres]

Sorry, changing the table to see what kind of blm's I get is about as far as I was trying to go. I only changed one scaler (33 to 36) to get a higher value in the last cell of table 3 and with the software I was using, when I did change the scaler it automatically recalculated all the gps values in the that table for me so watch out for that. Maybe if you change the scaler using a hex editor maybe tunercat will recalculate the table entries for you when you open the file but you'll have to check on that.

As I stated above I'm not exactly sure which way the table lookup is happening but I don't believe that your reported gps will change so I'm guessing that the code is seeing pp2 counts from the maf and looking up what gps to use to calculate fuel delivery since when I raised the gps values in table 3 and 4 it lowered my blm's in cell 15 which is what I wanted so it had to be adding more fuel that way. I'm not sure if the gps numbers in the maf tables have an exact correlation with gps that you see on a scan tool...could be two different things..just an idea. If it was looking up gps based on the maf reading then getting the pp2 counts I don't see how it could add fuel in my example as now it would be looking up a lower pp2 count after I raised gps values in a particular table.

Thats the first time I've seen the use of the maf scaler in the LV8 formula so I'm actually glad I didn't change but one scaler as I don't want to upset the LV8 calculation if I don't have to.

I believe the reason for the different scaler values is so each table has a nice slope if you use tunercat to graph each table you'll see this as each table is nice and linear until they decide to max them at 255 and this way their able to keep everything in a 0-255 total range which is a must as xff is all you've got to work with.

From Bruces's chip info on gnttype.org here's how the gps in the maf tables is calculated so you can see how the scalers are at work if you run through a few:

If you take the scaler and multiply it by a particular entry(converted to decimal from hex), and then divide it by 255 that tells you what reading in gm/sec that particular frequency represents.


Hope that helps.

 

[2QUIK6]

Thansk for all the help Mark. I've been tweaking the tables all this morning and I've got my BLMs all around 125-135 now, they were 115 at idle and 153 at highway cruise. Got one last little tweak as I changed the values for 35gps to about 90 gps for the highway cruise, but need to fine tune that 25-35 now which is right where the BLM cells change from cell 11 to 15, it gets real lean right before and immediately after the cells change but once it stays at 40 or so gps for a few seconds it goes back down to 128-130.
Also manages to make it where it doesn't rev up real high at cold startup by adjusting the idle vs cooland and IAC steps in one of the tables.
Oh yea, Tunercat can't handle changing the scalars right now, they said they should have a new t31 def in the next few weeks that will handle it, they also added the MAT diff multiplier table so now I can adjust fueling changes for changes in air temp/wheather.

 

[BoostKillsStres]

Glad I could help. Thanks for the Tunercat info.