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AEM UEGO shows AFR but can't be logged

Posted: Wed Aug 25, 2021 2:02 pm
by fwlrmusic
Hey,

I'm helping a friend get his RB25DET set up for tuning. He has a UEGO and we've wired up the serial connection and have gotten the AFR to read in the wideband box in nistune.

The wideband doesn't show up as a source though in the nistune datalog.

Am I missing something?

Thx!

Re: AEM UEGO shows AFR but can't be logged

Posted: Sat Aug 28, 2021 3:48 pm
by Matt
So you are not seeing the LAFR/LO2 parameters in the software with Wideband 1 configured as UEGO in File > Config > Wideband?

So it is not in the logger drop down?

Re: AEM UEGO shows AFR but can't be logged

Posted: Wed Sep 01, 2021 10:29 am
by fwlrmusic
OK update!

We are able to log but the serial data is becoming corrupted and giving a frame error in nistune. I have included the raw serial data where I saw the weird ascii character fly by. I'm assuming this is what is tripping nistune up.

We have tried grounding the ground pin on the serial connector to the connector itself. Also I was able to get it to log for 15 minutes by holding my thumb on the transmit line which led me to believe that maybe its noise related (thumb acting as a capacitor?).

Open to ideas!

Re: AEM UEGO shows AFR but can't be logged

Posted: Wed Sep 01, 2021 10:38 am
by fwlrmusic
confirmed that as long as I hold my clammy thumb on the pins of the connector the serial data is happy... weird.

Gonna try soldering a 2Mohm resistor from TX to ground, and if not build an RC filter on that pin.

Re: AEM UEGO shows AFR but can't be logged

Posted: Wed Sep 01, 2021 10:24 pm
by fwlrmusic
Tried a few different resistors down to 100k and nothing helped. I'm thinking of trying a different serial adapter. It's so weird that we can go out logging as long as I hold my thumb against the backside of the pins, then within a few seconds of letting go the serial data freezes...

Re: AEM UEGO shows AFR but can't be logged

Posted: Fri Sep 03, 2021 9:30 am
by Matt
I could look at noise immunity, but that is difficult. I would suggest a capacitor on the line or another USB-serial converter

Try about 0.1uf between the lines and see if that helps:
https://en.wikipedia.org/wiki/Decoupling_capacitor

Re: AEM UEGO shows AFR but can't be logged

Posted: Fri Sep 03, 2021 10:19 am
by fwlrmusic
I actually did try a 0.1uF cap from the line to ground and it shunted the whole signal. We tried two different laptops. I'm thinking a new serial converter is in order.

Re: AEM UEGO shows AFR but can't be logged

Posted: Sat Sep 04, 2021 6:58 am
by Matt
Agreed. I've seen some pretty bad ones (which mess up all the data) over the years. So I only stick with good brand ones