i did a search for vemaster, and i couldnt get a good answe, but it seems like its a program where it 'sorta' adjusts ur VE tables... where can i get this program? is it free (doubtful lol) and also does it work with OBDII? and for 'scanning' can i use autotap? seems like it wouldnt even be useful for me since i use a MAF though...

now onto BLMs... what exactly are they? how do i use them? how do i know what my BLMs are? only thing i know is u want ur BLM to be 128 or something at WOT, and if not u can force the PCM to do so on lt1edit... I looked at autotap, and i didnt see anything that said 'BLM' or anything, so i have no clue how to log that... I believe i need some o2s sensors that are working pretty good for this since my rear o2s keep taking a ****... maybe the harness is FUBAR

can someone enligthen me?

thx

 

BLMs are Block Learn Multiplyers. The PCM has 2 tables for these, short and long term. BLMs are used by the computer to adjust the fuel trims to make a perfect 14.7:1 AFR. The tables look alot like this and are based on MAP and RPM:

RPM
0 900 1200 2000 redline
0 +-------------------------------+
| | | | |
| 0 | 1 | 2 | 3 |
| | | | |
30 +-------+-------+-------+-------+
| | | | |
| 4 | 5 | 6 | 7 |
M | | | | |
A 50 +-------+-------+-------+-------+
P | | | | |
| 8 | 9 | 10 | 11 |
| | | | |
80 +-------+-------+-------+-------+
| | | | |
| 12 | 13 | 14 | 15 |
| | | | |
100 +-------------------------------+

BLMs only work in closed loop and not in PE mode (WOT). Short term BLMs change in real time and long term change with trends.

There are 19 BLM cells, the first 16 (0-15) are based on RPM and MAP, while the last 3 are for idle, deceleration, and EVAP canister usage.

VE Master is a program that takes the LT BLMs and adjusts the VE tables to set the tune so the BLMs can be around 128. It is a good program for what it does, but if your o2 sensors are working correctly, I dont really see how it would help much.

 

you mean if they are not working correctly right?

how do i check my BLMs?

 

You can see your BLM's with scanning software.

I just used VE master about 30 minutes ago, and it lined up my BLM's almost dead on to 128 LT. Then I manually adjust my VE tables to get the target BLM of 128.

VEMASTER:http://home.comcast.net/~jgeorger/vemaster/

 

You have an '97 car, so it should be an OBD2 PCM. Right? If your PCM is like my '99 PCM, you will have 22 fuel trim cells (FTC). The above post are a bit confusing. The table shown by disco192, shows the individual fuel trim cells, they are arranged by MAP vs RPM, as he said. There is a specific fuel trim vaule in each of these FTCs. For example, FTC 12 might have a LFTF value of 10%, while FTC 2 might have -5%.

Another confusing matter is that the terminology between OBD1 and OBD2 stuff is different.
OBD1 ............................. OBD2
BLM (block learn memory)= LTFT (long term fuel trim)
INT (Integrator) = STFT (short term fuel trim)

For OBD1 ECMs, they stoic value for BLM is 128 (no fuel correction), while for OBD2 PCMs, the stoic value is 0% (no fuel correction).

You can check what BLMs or LTFTs that yiou are running at by the use of a scanner like AutoTap.

 

The LT1 OBD-II PCM's are completely different than the LS1 OBD-II PCM's. The grid posted above is correct, and in addition there are Cells 17 (coast down) and 18 (open loop load).

Read the "Air/Fuel Management" section of my online scanner writeup for info on the LT1 PCM's.

http://members.aol.com/InjuneerZZ/ScanMast.htm

 

Injuneer, that is a great article, everyone tuning on an LT1 engine should read it.

 

good read, but it wont help with my problem that i'm having

 

What problem are you having? BLMs in autotap would be represented by a percentage instead of a number. They may be called LTerms or fuel trims as well.. not BLMs.

 

As far as I see it, tuning with Vemaster just fixes the problem assiciated with extreme tuning (basically happens when you max out your BLMs). To this point, it doesnt do much good htat the oxygen sensors cant do themselves.

You are better off strapping the car to a dyno, getting the AFR and sending it into a mail order tuner (with all your info) because they can prolly hit the nail on the head as well as a dyno tune.

Sorry, but I hate seeing people waste their money on local shops who "dyno tune" their cars for $500+ and only touch the PE tables (and barely the spark tables). That just drives me insane.

... I know there are honest shops who actually do awesome work, I dont want to trash talk them... just make sure you know what you are paying for. I am just ranting because i know some guys who paid alot of money for simply PE table tuning on OBD1 which I could have easily done with a dyno and AFR.... makes me mad.