getting things straight: genIV LMG, E38, wideband O2 and the VVE table

[harascho]

I did the first logs MAF-less and here is what I got.

I had a hard time filling the cells of my BEN table... not an easy task to perform



The Tahoe ran fine with the settings of the VVE tutorial thanks to the good work of Simon. The only thing I noticed was a very harsh 1 -2 shift.

Harald

While preparing the attachment I took a look at the log... I still have some LTFT activity? Only a small amount, but still there..... To be on the save side I also posted my tun file...

[swingtan]

OK, here's what I'd do.

• First, fix the knock. Drop the timing in those cells to stabilise the spark. Is that a stock spark table? It looks very high. Then when you look at your IAT spark table you are adding yet more timing.
• Next, when logging TP% select "ETCTP" and you should then get a true 100% WOT reading rather than 83%.
• When logging for VE corrections, be gentle with the throttle and try and hold it steady for as long as possible. Don't go stomping on it all the time as it doesn't give good data.
• The VVE looks rather bad in that tune. Is that how the stock one looked? If not, then copy the stock values over again, don't forget to generate the coefficients and VVE before saving.

You should be right to try adjusting the VVE after that.

Simon

[harascho]

Ok Simon,

first the knock...I will take care of this first. I advanced the timing and I missed a high load testdrive after that. I only adjusted the high octan table and kept the low octan table stock for safety if I ever advance too far.

Any comments on the LTFT which are still about 4% in that log...I expected them to be zero??

The VVE in that tune.. I copied the original one in that table with the changed boundarys. For me the original VVE looks odd in the beginning..??

Harald

[harascho]

Here are pics of the original VVE and the VVE according to the tutorial which will be used for data logging. I checked all of the tutorials points a second time and I ended with that shape of the VVE.

Any ideas why my LTFT are still active?

To the spark.. I worked on the high octan spark table and reduced the timing in the cells with knock.

[swingtan]

Hi Harald,
I'm not sure why the LTFT's are displaying like that but it may have something to do with them not being reset. Try clearing the fuel-trims from ScanTool...

• Connect the laptop to the car via the V2, ignition on.
• Open ScanTool and connect to the vehicle.
• Go to the DVT tab ( F12 ) And click on "Activate".
• In the DVT window, click on "Fuel System"
• On the top row, click on "Fuel Reset" under "Fuel Trim Reset".

The stock VVE tables are also rather bad to start with. I've had a play and tweaked them a little to reshape them ( read over written them with near stock Holden 6Lt data ) which should be a bit better. Being the 6Lt version they will be a bit rich, but it's better to be rich than lean.

Last point here, you have AFM active on the tune, so you will want to turn that off in your tune. I think that setting B0921 to "NO" should do that. Once you have set up the normal VVE, you can turn it back on and then work on the AFM VVE.

Regards,

Simon.

[harascho]

You are a very big help for me. I will try the modified tune this evening after work. The LTFT are strange 'cause they changed in my log althought they should be disabled. I will check if resetting them will the trick.

Harald

I am curious how the VVE table looks now..

[swingtan]

It looks very much the same as in the VVE guide, as I used the same one for that

[harascho]

I did a nice testdrive today. After some adjustments to the High octan spark table KR is alomost 0 but with the modified tune file from you (basicly my file with your VVE map..) my Tahoe starts and dies immediately.

I compared the two files, the only differences are B8001 and B8051 (I copied your VVE map into my tune file before..). I flashed my tune file and the Tahoe ran..

To be on the save side I post the two tune files here together with my logged file.

Harald

[harascho]

I took a second look at the two tun files. In the Tuning tool I could take your values (VE coefficients B8001 and B8051) and store them in my tuning file which works in my Tahoe.
Here is a log I took a few minutes ago and also the tun file

Harald

[swingtan]

That's looking pretty good now.

In the log file you can see it's running a bit rich, but it's pretty consistent. Try the Auto VE process with that data and see how the VVE drops in the logged areas. Then smooth out the big spikes and dips, as well as the borders were your data ends and the original VVE remains. It'll be fairly obvious once you have applied the data. You don't want any big steps in the VVE.

Another point to remember is that the generation of the co-efficients will do a fairly heavy smooth across the changed cells and zones. If you have large changes in single zones, it will effect all the data in that zone. So you can cheat a little and alter any cells that have had no data applied, by setting them to similar values to the other cells in the same zone.

It looks like you're on the right track though.

Simon