Datalog and Analysis
Now, If you have followed the above your car should be running and driving pretty well. I have found that the fine tuning is best done by taking a datalog and doing both manual and algorithm analysis.
Do you have MegalogViewer program? If not, Its time to get it. It usually comes with the paid Tunerstudio bundle. Here is a tutorial to use it. At this point you will be making small changes that are likely finer than VEAL can do. So, A drive with datalog followed by analysis is the way to go. I will say that the MLV program can be used with most other ECU systems. The trick is to know how to change file formats so that the data is present in the correct fields. If you are familiar with data formatting I can answer questions about this.
In TunerStudio (TS) you will start a datalog and then go for a drive. The idea here is to capture lots of data at all 4 corners of the fuel curve. This means, lots of on/off throttle, loaded in different gears and different RPMS. also, Don’t start the datalog until the engine is fully warmed up.
Once you have stopped driving, open your log file into MLV. Then open your tune file using the dialog button on the right center. I will pull down the lower dash section so I can view the VE table and AFR target table along with the run trace. It should look like this.
Ref Pic 16
Once loaded you can scroll through the log file and look for certain areas. You can right click in middle of graph and navigate quickly to certain conditions. The space bar can be pressed while driving to put a time stamp marker in the file. mDatalogs can also be taken using a mobile phone and blue-tooth connection. The MSDroid program works really well compared to ShadowDash. I will not go into details about this now. We can cover later if there is enough interest.
Next, click the VE analyze button. This will let you quickly see where you are lean and rich relative to the AFR targets. Use the large VE analyze button to run the analysis. When finished the VE table will be color coded; Red means it is rich and blue means it is lean. This quickly allows you to spot trouble areas. This is the analysis of your latest datalog. You can see the rich spot right below 4krpm at 87kPa and then going lean with anything needing more throttle. This also shows that you need more fuel up top. And you also need to start pulling to RPM cutout to get that 6500 rpm column.
If you run the mouse and hold over a cell it will tell you what the previous value is and how rich/lean it was. The mid-range is making small changes. For example: 2400rpm@75kPa is only a 1 VE value change. But the top end is really lean. The 4400rpm@100kPa went from 190 to 242. That’s a big change.
Make sure you click “accept new table” and then “save tune as” to commit to new file for loading.
Ref Pic 17
