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How To :: MyCal :: AFR


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This is a How-To guide to get you setup and reading A/F Ratio's with your MyCal device.


To calculate AFR you will use one of the calculator functions available in the MyCal device.


Part 1 - Install the Calculator

1. From the Main Menu go to Settings --> Devices --> Manager

2. Select the next available "Unused" slot and tap "Add Device". Take note of the letter used and it will be an easy reference for later steps.

3. Click the left or right arrows till you see the Calculators device list

4. Scroll down and tap on "Rescale Signal Calculator" and then tap on "Save"

5. If it doesn't take you back to the Devices menu tap on "Exit" and then tap on "Parameters"

6. Tap on the left or right arrows to the newly created Rescale Signal Calculator and tap on "Change"


Part 2 - Configure the Calculator

The Parameter menu is where you will set everything to calculate AFR. Use the following settings:


7. For Input Signal you will want to scroll through the ODB Generic signals and choose "O2 Bank 1 Sensor 1 Lambda (Wide)"

8. For Multiplier Signal you will want to use the left and right arrows and scroll to your newly created Rescale Signal Calculator and choose "Constant Multiplier"

9. The Multiplier Sign should already be set to 1 (positive one). If it is set to -1 (negative one), change it to 1 (positive one).

10. You will need to change the "Constant Multiplier" to properly calculate AFR. If you fill up with 10% Ethanol gasoline then you will use 14.13. If you use pure 100% gasoline you will use 14.7. If you have some other ethanol content you will need to Google the Stoichiometric ratio for that ethanol percentage.

11. For Offset Signal you need use the left and right arrows to to find your newly created Rescale Signal Calculator and choose "Constant Offset"

12. Set Offset Sign to 1 (one positive)

13. Leave Constant Offset as 0 (zero)

14. Change name to something legible. I used "AF_B1" for Air Fuel Bank 1.

15. I left Units and Precision unchanged.

16. Exit all the way out to the main menu and click on Gauges. Tap a gauge to set. Scroll left or right to find the Rescale Signal Calculator and look for AF_B1 that you named in step 14. You should be reading a value somewhere around 14.7.


This has given you the AFR for Bank 1. Now for Bank 2, do ALL these steps again but with only 2 changes. For step 7 and choose "O2 Bank 2 Sensor 1 Lambda (Wide)". For step 14 name it AF_B2. This will give you the reading for Bank 2.


I have added a couple pics of the Parameters screen to give you a visual guide for the values.




Thanks to Scrming and darreli for the direction needed to get this going for me. Would have have been able to do it without their help/guidance.





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