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Discrepancy between Tunerstudio and PLX air-fuel ratio meter values

Practical Standalone Tuning

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The numbers displayed on the PLX air-fuel ratio meter and the numbers displayed on Tunerstudio's AFR gauge are displayed with a difference of about 0.6.

I think the numbers on the PLX air-fuel ratio meter are probably correct, and the numbers on Tunerstudio's AFR gauge are displaying an understated air-fuel ratio for some reason.

Why is this?

I thought that the EGO CONTROL might be the problem, so I tried turning it off, but there was no change.

---My Tunerstudio---

The version of the TunerStudio I use is TunerStudio MS Ultra 3.1.08.

Connected to MS2 EXTRA 3.4.4 Release 20201006.


DM-6 Multi Gauge SM-AFR

Attached Files

Is your MS2 getting the O2/AFR info from the PLX, or are you using a different wideband controller. if using the PLX (which i believe is an analog voltage connection to the Megasquirt) then have you connected the grounds to the same point? Lastly, you might just need to calibrate the MS2 to match the PLX display.

Ground offset or resistance in the signal wiring commonly skew analog data.

If your wideband controller has a sensor ground wire, be sure to wire that to an ECU sensor ground input.

Otherwise check resistance on your signal wire connections.

And for the future, a CAN based wideband system avoids this since the data is transmitted digitally.

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