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View Full Version : SD Tuning a 98-00 Fbod w/ LTFT's



TAQuickness
January 26th, 2005, 05:31 AM
I've been working on a SD tune for my 00 M6 WS6 and thought I would post my notes on how to do it here.

Gotta start by saying "Use at your own risk!" I am not responsible for anything you do. I found most of this information by searching various sites and asking questions all over the WWW. If it looks like you wrote this origianally, you probably did. Thanks to everyone that posted there HOW TO's that make up this HOW TO :D

Note - You want to try and complete this process in the same day.

Note - 01-02 Fbod PCM's do not have a Backup VE table. In the case of 01-02, disregard all steps relating to the back up VE table.


1) Download your current tune, save it, and make a copy on CD.

2) Make a copy of the downloaded tune and rename it
(M6ws6.SDtune.tun)

3) Open the SD tune file and start with the basics
a) copy the high octane spark table to the low octane spark table (the PCM will use the low octane table when you disconnect the MAF later). If you do not do this, the car will run like crap.
b) disable the MIL light ONLY for P0101, P0102, & P0103. This keeps the SES light meaningful.
c) Enure all other parameters are correct
d) save the modified tune

4) Reflash your PCM with the new base SD tune

5) Pop the hood and disconnect the MAF

6) Open EFILive and create 4 custom MAPs (these will mimic the row and colum headings of your main and backup VE tables

a) MAP 1 - Data Parameter = LONG TERM FUEL TRIM - BANK 1, Column = INTAKE MANIFOLD ABSOLUTE PRESSURE kPa, Row = ENGINE RPM (RPM). Set the column and row labels the same as the MAIN VE TABLE. Save as MAIN VE LTFT 1.MAP

b) MAP 2 - Data Parameter = LONG TERM FUEL TRIM - BANK 2, Column = INTAKE MANIFOLD ABSOLUTE PRESSURE kPa, Row = ENGINE RPM (RPM). Set the column and row labels the same as the MAIN VE TABLE. Save as MAIN VE LTFT 2.MAP

c) MAP 3 - Data Parameter = LONG TERM FUEL TRIM - BANK 1, Column = INTAKE MANIFOLD ABSOLUTE PRESSURE kPa, Row = ENGINE RPM (RPM). Set the column and row labels the same as the BACKUP VE TABLE. Save as BACKUP VE LTFT 1.MAP

d) MAP 4 - Data Parameter = LONG TERM FUEL TRIM - BANK 2, Column = INTAKE MANIFOLD ABSOLUTE PRESSURE kPa, Row = ENGINE RPM (RPM). Set the column and row labels the same as the BACKUP VE TABLE. Save as BACKUP VE LTFT 2.MAP

7) Select you pid's for logging. At a minimum you will need to select MAP, LTFT B1, LTFT B2, & ENGINE RPM.

8 ) Start the car and let it warm up (ECT above 160) then reset the LTFT'S

9) start loggin and drive for a minimum of 50 miles. During this drive the car will likely run like crap. Be patient and let the car learn the fuel trims. You want to stay out of PE while you are driving. You also want to get a fair amount of stop and go as well as hiway cruising in.

10) For the next part, I use an Excel spread sheet, but I imagine pencil and paper would sufice. Start with the BACKUP VE table. For each cell in the back up VE table you want to add the average of the LTFT B1 & LTFT B2 of the respective LTFT cells.

Assume you are working on 400 RPM and 20 kPa, the formula looks like this:

Backup VE Table + ((LTFT B1 + LTFT B2) / 2) = new Backup VE table value

or:

40 + ((-11 + -12)/2) = 28.5

or :

40 + (-11.5) = 28.5

11) repeat step 10 but apply it to the MAIN VE table using the MAPs you created for the main VE table

12) Save this tune and reflash your PCM.

13) Repeat steps 8-13 until all your LTFT's are between -4 and 0.

After you have completed the SD tune, you can either leave the MAF disconnected, or plug the MAF back in and start scaling your MAF table to get your LTFT's back between -4 and 0.

I haven't decided yet if I'm going to run the SD tune all the time. If I get into rescaling the MAF table, I'll make a new post with tips on how to do that.

If anyone has anything to add, comment, flame, or what ever, feel free.

Dirk Diggler
January 26th, 2005, 06:10 AM
Is flashscan able to re-write the whole vcm? If so dload an 01+ vcm tun file and re-write your pcm with it. Change the vin number when you are done. Currently that is how i am running my 00. I have a 01 vcm file that i re-wrote with the other software the only thing that sucks is i cant change my vin back with their software and if i did it with EFILive their software compalins

That is how I got around foooling around with that backup table. If you ahve a 98 PLEASE DONT DO THIS or EVEN TRY

Also you can make a map that averages banks 1 and 2. I made one but i am not at home right now to post it

looked something like this

(LONTFT1 + LONGFT2) / 2

This was used to fill in my ve tables and anything else where i was looking at ltrim information

TAQuickness
January 26th, 2005, 06:50 AM
I'm using Excel to calculate the average ltft from both banks. I still like to log them individually so I can see if anything is taking place that shouldn't be (like one bank more rich or lean than the other).


I'm not sure if flashscan will download the entire thing. If I had only the main VE, the MAF would be history.

Dirk Diggler
January 26th, 2005, 06:56 AM
Can it re-write the enitre VCM