You've got your wideband hooked up and wired in, but can't get it to display correctly? It could be the formula, here is how to figure out what you should be using. It's kind of complicated, so if you need help feel free to email us and we'll help you out.

  • The Wideband should have come with some sort of documentation. Use this to gather the info below, if it did not come with anything, you will need to call the manufacturer or search their website for this info.

  • We Need to Know What Air/Fuel Ratio is equal to 0 Volts.
  • We Need to Know What the Max Voltage Range for this Wideband is.
  • We Need to Know What Air/Fuel Ratio is equal to the Max Volts. (4 or 5 volts, which ever it may be)

  • Once you know this information you can figure out what the formula should be.

  • This is the start of the Formula: (Volts*X)+Y
  • We take the A/F equal to 0 volts to figure out the Y.
  • We take the A/F equal to Max Volts to Figure out the X.


  • Here is an Example:
  • V*X)+Y
  • 0 Volts = 10/1 AFR. – Let’s Call this Value1
  • 5 Volts = 18/1 AFR. – Let’s Call this Value2
  • (V*1.6)+10


  • To Figure Out Y: Y is always equal to Value1, so Y=10 in this example.
  • To Figure Out X: Take Value2 (18 in this example) and Minus Value1. So 18-10=8 in this example. Then divide that number by the max volts. (5 in this example). 8/5=1.6.


  • Here is another Example:
  • (V*X)+Y
  • 0 Volts = 10/1 AFR. – Let’s Call this Value1
  • 5 Volts = 20/1 AFR. – Let’s Call this Value2
  • (V*2)+10


  • To Figure Out Y: Y is always equal to Value1, so Y=10 in this example.
  • To Figure Out X: Take Value2 (20 in this example) and Minus Value1. So 20-10=10 in this example. Then divide that number by the max volts. (5 in this example). 10/5=2.