Free air calibration issue


I have been having a weird issue with my spartan 3 lite hovering around 1.15 lambda with little fluccuation and comparing this to the dyno lambda where it was rich all of the time. I have had the sensor and controller for a few weeks now.

I have confirmed the sensor setting is correct LSU 4.9

I wanted to complete a free air calibration to see if there was an issue.

When completing the free air calibration I got a calibration value of 340282366920938480000000000000000000000.000000 which doesnt seem to be correct or reasonable. I also get the same calibration value if the sensor is disconnected.

What is my issue here? Sensor is damaged? Bad wiring?

Screenshot 2023-05-23 200442

When you do a free air calibration:

  1. sensor is out of the exhaust and in free air
  2. power on Spartan 3 with the sensor connected
  3. wait about 2 minutes until you see the red LED being solid and not blinking, this means the sensor is at operating temperature
  4. issue the “DOCAL” command and that will do the free air calibration and display it over the serial connection.