AEM X Series AFR not matching Megasquirt - CANBUS
 

Hi guys. I used to have an Innovate MTX-L wired to my Megasquirt using the analog signal. I just now swapped out the Innovate for an AEM X Series UEGO and I'm now using the CANBUS protocol to read the AFRs. Everything functions as it should, but I noticed that the AEM is approximately 0.5 leaner than what is showing in Tunerstudio. I'm not sure if maybe my CANBUS settings might have something to do with it? Anything I can play around with to try and get this closer to even? I've attached my tune to help with troubleshooting.

I used the following threads to help me with my CANBUS settings:
https://www.miataturbo.net/megasquir...9/#post1470957
https://www.miataturbo.net/megasquir...not-ms3-98941/

So I went back and checked my wiring, everything looks to be fine. I also have the gauge end of the CANL and CANH wires terminated with a 120 ohm resistor across them.

I do not, however, have the analog signal wires hooked up. Do I need these hooked up if I’m using CAN? This thread suggests that I should?

https://www.miataturbo.net/megasquir...ctions-106404/

Dumb question but did you calibrate your new wb in tunerstuido?

I might be dumb to be honest because I thought the calibration in TS was only if using the analog signal and not CAN? If I still need to calibrate the voltages though then that's my bad.

Well I sent AEM support an email to see what they say since I am having a really hard time finding any info on this. I just tested again yesterday and when Tunerstudio shows 14.8 AFR, my AEM gauge shows 15.3 using CANBUS. No idea what is going on.

CNA BUS is literally sending you the number encoded in HEX....like if the display send 14.7 then the canbus message has to be 14.7

are you sure you set it up correctly in TS?

show us some screenshots.

Sure, I attached some screenshots from what I set in my Megasquirt. If this all looks good, is it possible something could be up with the gauge? Its a brand new gauge so I mean if there is something up with that then I'll have to try and get AEM to warranty me another.
https://cimg3.ibsrv.net/gimg/www.mia...354d465dc3.png
https://cimg4.ibsrv.net/gimg/www.mia...c5b25bf6f3.png
https://cimg5.ibsrv.net/gimg/www.mia...fbddf628e2.png
https://cimg6.ibsrv.net/gimg/www.mia...f42c9d4fe4.png
https://cimg7.ibsrv.net/gimg/www.mia...5dc0017bd5.png
https://cimg8.ibsrv.net/gimg/www.mia...5c2a172960.png
https://cimg0.ibsrv.net/gimg/www.mia...fb8cf04be6.png

In case anyone comes across this issue in the future, I figured it out. For some reason, my Stoich AFR was set to 14.1. As soon as I changed it to 14.7, the reading is spot on. I have absolutely no idea why mine was set like that, but all is good now.

fuck off!!!
where...i had the same issue as you :(

So under the general settings, my stoichiometric AFR was showing 14.1. Changed it to the gasoline value of 14.7 and it started reading correctly. How did you fix your issue?

i dind't...i resorted to going back to serial....but imma try this.

thanks!

When I tried to go back to CAN with my AEM (since I'm back to 1.5.2 FW), I cannot get it to work. If I set it as "Innovate", it works, but is not correct values. If I put it to AEM X Uego, I get "0" AFR.

Make sure voltages are setup in calibration settings.

I’m having the same problem, anyone found a solution?

I’ve had Diyautotune check my CAN settings, the last thing i have yet to try is disconnect my analog 2 inputs. (I currently have analog and CAN both hooked up).