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

[harascho]

what a long title... but it tells it all

I installed a LC-1 wideband did some logs and tried to have a close look at the VVE table.
From the first log it seems I am running in the area of 14,2:1 average, pretty rich...

I did as described in Swingtans E38 VVE dial in guide.

Some comments:

I did step by step as described, disabled the LTFT, STFT, DFCO and I set the cruise and PE AFR as in the tutorial.
Then I disabled the MAF and started looking at the IAT compensation. As it is still cold in Germany I only could manage to get an IAT log with temps from 5deg Celsuis up to 30deg C. I could not see any drift in the WB AFR so I was ready for the next step.

I could not find parameter B8101 as on page 9. (V2 plugged into Laptop) Only B8001 showed in the search.

Then next thing after preparing the .tun file as in the tutorial and disabling the MAF.. the engine started and died right away.

So I am confused.. ( as usual.. don't worry..)

Any ideas what I might have mixed up?

Harald

[swingtan]

If the engine started then died, it's probably still using the MAF readings for air flow metering. By disconnecting the MAF, you are now telling the ECM that there is no air flow, so it doesn't add any fuel. To fix this, ensure that the MIL code settings are correct....

• Under DTC Type, set P0101 to P0103 to "C: Non Emissions"
• Under DTC MIL, set the same parameters to "No MIL"

If you have physically disconnected the MAF, then the stock settings for C0301 to C0312 should be fine to fail the MAF. If you disconnect the MAF and alter the MAF test settings, you may end up with a condition where the ECM thinks it's still working fine. Do a sanity check on the MAF parameters and ensure they will work OK.

For the reference to B101 on page 9, I think you have an old version of the guide. The latest version is 1.9 and has a few corrections in it.

[harascho]

just in time.... I will check that out tomorrow.
I'll keep you posted.

Harald

[harascho]

in the latest version I found:

Parameter: B8020
The stock settings here seems to assume that the MAF will work for all RPM ranges over 3000 RPM. This won’t work when the MAF is turned off. Reset these boundaries to something that gives you a series of more sensible zones for your expected RPM range.
Look at where you would normally be driving and set the zones accordingly. Something like 2000, 3500, 4500, 5500 RPM may work well. This table has a big effect on the VVE shape.

Should I use here the rpm's I touch most in normal driving situations?

that would be 1000 -1800 - 3000 - 3800 for example. It's a rare occasion that I touch the 3000's


Parameter: B8021
As with the previous setting, this helps to shape the VVE table. Adjusting the setting to make the zone match expected driving conditions will help a lot. The stock settings are pretty good, but you may want to drop the “MAP 1” values to help set the idle airflow.

NOTE: At this point, ensure that the “UNITS” set up for B8021 match with B8001. In other words, make sure both tables are using kPa or PSI. Mixing these up will result in the VVE zone boundaries not being where you expect them to be.

Before moving on, you should do 3 things…
1. Go to B8101, still searching that B8101.. press <F4>, select all cells and “copy with labels”
caught B8001 and tried to copy with labels and had an error message...

Am I looking in the wrong places?

[swingtan]

B8020: I'd set those so that the RPM ranges you normally drive at, are inside the zones. Don't make the "normal RPM range" the boundary as you want those ranges as close to the middle of the zone as possible.

B8101: Have you started Tune Tool with the V2 connected? Note the paragraph just above the section titled "Parameter: B8020". If you do not start the Tune Tool with the V2 plugged in, the VVE tables will not show up.


Simon

[harascho]

hi, I worked a little more on the VVE Table, but I am still confused with the preparation.

As in the tutorial I copied the B8101 table then modified B8020 and B8021 and saved that progress in a new file name. Next step was I opened that new tune file , went to B8101 and pasted the original B8101 table back in place.
here are pics of the original table and from the then different table. From a first look I don't see any difference at all. Did I miss a step ?
Next was generate Coeffs.....
I recieved an error message like:
" Zone #12 is too small. Zones must ne at least 3x3 cells"
where is my fault? Ideas?

Harald

[swingtan]

It looks like you have set the lowest RPM range too small. The way I chose the zone boundaries was to look at what idle RPM I have, and make that near the centre of the first RPM zone.

So say my idle was 700 RPM, I set the lowest RPM boundary at 1000 RPM.

Then I did the same for cruising, say I cruise at 1600 RPM, so I'd set the next boundary at around 2500 RPM.

I then jumped to the end of my RPM range, so say I shift around 6200, then the highest boundary should be below my shift point, so I might make that 6000.

the last boundary I just did an average to make the graph look straight. as I said in my previous post, do not make the zone boundaries at your normal engine operating points.

Another tip is not leave the MAP boundaries the same across the RPM zones. Unless you have a reason to have changes between RPM zones, there should be no reason to change them. As mentioned in the guide, the stock settings are pretty good and may not need any changing.

Finally, you need to copy the VVE data in B8101 from the tune before you altered the zone boundaries. Basically you are going to put the stock VVE data back into the changed zones to correct the shape. the final result of this step should be a VVE table that looks the same as the stock VVE.

Simon.

[harascho]

swingtan, with your help I was able to get it right.. logging will be today..

What response speed of the LC-1 do you use normally? The instant response seems to bee too fast and the signal is pretty fuzzy with this setting (I wired the LC-1 with a good GND source....only the cable shield from controller to my V2 connection is not connected at the V2 side. Should there be a connection from shield to GND or is this connected in the controller?.. I bought my LC-1 used so I don't know how the wires ended in the OEM version..)

Harald

[swingtan]

I don't use an LC-1 so I can't comment. I use a TechEdge and run the serial connection into the V2. Post up a log file and I'll have a look at it for you.

Simon

[harascho]

I will post some logs later I am still stuck in my office...
It will take me some more hours to come back with some logs.
What time difference do we have ( Germany - Melbourne/Australia)?


Harald