MAF CAL Upgrade – “Tune” Function
November 13, 2024A new “Tune” function in MAF CAL will take a lot of the work out of calibrating the MAF sensor signal.
MAF CAL is a product from MoviChip which allows the users to calibrate their MAF sensor signal to optimise engine fuelling.
There are a number of use cases where the MAF CAL is suitable and where it is not, I’m not going to expand on that in this article but you can read more here.
The MAF CAL can plus/minus the MAF signal according to MAF signal +/- 50% up to a maximum output voltage of around 4.9volts.
Tuning is best done by datalogging STFTs against MAF sensor signal (with an external datalogger) and adjusting the MAF sensor signal accordingly.
However, this process can get a bit involved if the datalog analysis has to happen outside the car ie not in real-time. There can be a lot of back and forth between car and computer until the signal has been calibrated with MAF CAL.
The new “Tune” function allows the analysis to be done visually in real-time (or after the fact). Using the Tune function bypasses a lot of the data analysis process as tuning can happen visually in real time. This will get the calibration in the ball-park. Fine tuning using a histogram that compares MAF signal against STFT is probably still optimal to get the calibration as good as possible but I would say visually analysing the data can get the user within 5%.
Before The Tune Function
The MAF CAL app has a diagnostic function. This function is to show us if the MAF CAL app is performing as anticipated and if not why not. In other words it helps us identify potential installation/wiring issues.
However the diagnostic function was not intended to be used while the vehicle was in motion, it was solely to tell us if the unit was wired correctly. This meant the data on the Diagnostic screen would update every three seconds or so. Too slow for visual analysis for tuning.
With The Tune Function
The Tune function, when activated, stops all the data being sent to the Android device, except the “MAF In” voltage. This allows the MAF In voltage to update every half a second on the MAF CAL Android app which is enough time for us to compare the MAF In number with the STFT in real time.
Using The Tune Function
The Tune function is designed for setups where the live short term fuel trim can be monitored visually on an Android device in real-time.
Using the floating windows feature in Android we can pull up our visual dashboard (Car Scanner is used in this demonstration video) showing out STFTs. And at the same time we can also have the MAF CAL app active which will show us our live MAF In signal from the MAF sensor with the Tune function in MAF CAL activated.
Depending on the circumstance, the adjustment of the MAF signal can be done as the vehicle is being used or alternatively, screen recording software such as AZ Screen Recorder can be used to record to screen for visual analysis later.
By comparing the current STFT against the current MAF In voltage we can optimise the adjustment, at this MAF In voltage, to get the STFTs as close to zero as possible.
In Summary
If you can display STFTs on your Android device, the new Tune function makes the process of optimising our MAF signal adjustment much faster.
