SM4 Manual
by
MRM-Racing
V3.0
32
Tuning with Datalogs and Mixture Table
This method is done by using the PC data logger to record the air fuel ratios. Then with
the both the data log and fuel table open, the software will search the data log for any
RPM and Load sites that do not match the target A/F ratio table values and display them.
You can then just select the sites you wish to be automatically tuned.
Press F8 to start the PC logger.
Now that the logger is running you can operate the engine through various RPM and
Load sites and allow the ECU to record the A/F ratios coming in from a Wide Band A/F
meter such as the Autronic A or B model analyser.
When you are finished with your run, you can stop the logging process by pressing F8
again. To display the logged data you press the F10 key on the keyboard and the data
will display on your screen.
Select the Mixture Table tab on the top of the data log screen. The "L" and "K" keys
switch between each tab.
Once you select Mixture Table press the F5 key and a pop-up box will appear and ask a
few questions about how you would like to interpret the data. This can be used to filter
out spikes in RPM and select what mode of mapping you have used in the cal file. Once
you have finished answering the questions just press Ok and then press Enter.
The software will extract the data concerning the A/F mixtures recorded and compare
them to the Target A/F ratios for each cell in the base fuel table you encountered during
the run and will display the values for each cell as a comparison.
If a cell is coloured RED it means the A/F values were very inaccurate and it will show
the actual A/F ratio VS. Target and how many times it sampled this reading.
If a cell is coloured YELLOW it means the A/F values were slightly inaccurate and it will
show the actual A/F ratio VS. Target and how many times it sampled this reading.
If a cell is coloured Green it means the A/F values were accurate and it will show the
actual A/F ratio VS. Target and how many times it sampled this reading.
You can use the mouse or the Arrow keys on the keyboard to highlight any of the
coloured cells and then press Enter. The software will then show a pop-up box and ask
you if you would like the ECU to fix the cells in the base fuel table that correspond to the
highlighted cell in the mixture table. Press Yes and then Enter and the ECU will calculate
the correct values and place them in the base fuel table.
Once you have fixed all the coloured cells in the mixture table, you close the data log by
pressing key Q, reset the datalog under menu Logger and PC logger reset. Store the
new settings in the ECU by pressing F4 and on the disk by pressing F2. Then do another
run similar to the first and then re-open a new data log and extract the new data in the
mixture table to see how much improvement was made.
If using this procedure on a dyno, you will only need to do two or three runs to completely
tune all the full throttle sites in the Base Fuel Table.
