Tunerstudio Erratic Afr reading
 

Hi everyone,
Just got my Ms Lab Ms3 Basic install in my car
One thing I notice that seems a little odd is my Afr gauge on the tunerstudio.
It jumps around even if the actual wideband gauge is showing steady 14.3-14.4
Did I set anything wrong on my megasquirt?
It doesn't happen when I had my adaptronic ecu install so I doubt it's the wideband.
By the way I am running the Innovate Mtx-l wideband and wired the yellow signal line directly to the db37 behind the ms3 basic unit.

Here is a video of it on youtube. Please help, thanks in advance!

I had a similar issue an it ended up being the ground I was using. Rev can tell you which one will fix your issue.

Hi 6speed
Did you end up using the ground on the db37 connector or different spot?
Thanks

As recall, I used a ground on the db37. It's been a few years though..

Sorry one more question. How about the mtxl setting? Did you change any setting in the mtxl wideband?

I'm running an AEM wideband. I don't remember changing any settings for it.

Mtx-l should not be grounded to megasquirt. Ground to the same point on the block as the megasquirt.

also you need to calibrate it in TS

Thanks, I'll double check my wiring and make sure everything is ok.

Hi ramensoop
By ground to the same point on the block do you mean that I'll have to run a wire thru the firewall and into the enginebay?
Or ground it on the chassis?
To calibrate it in Tunerstudio is using the "calibrate AFR table" correct?

Thanks!

Sorry forgot this is probably a plug and play setup. Ground the mtx as close to wherever the megasquirt is grounded as you can.

Yes calibrate afr table, choose custom linear wideband and and try these settings. Should get you within .1 or .2 of what the gauge reads

.22v = 7.35 and 5v = 22.4

What is your lambda lag factor set at?

Hi PSI,
Do you mean the setting in LM programmer? I cant find my usb to serial cable. Im ordering another one hopefully it will be here Tuesday. What setting are you using? Thanks

I tried using different power and ground source this morning. It seems a little better now, but it might be me getting used to seeing that in tunerstudio. I'll post a video of that later today when I get home. Thanks

Under general settings you will find lag settings for your sensors. Most are set at 50, a lower setting will smooth your readings.

Looking back at my problem I changed from wire listed as ground, to wire listed as sensor ground on the db37 connector and my afr's straightened out.

the problem with using sensor ground for the mtx-l is that both the o2 sensor and its heater use the same ground wire. It should not be connected to sensor ground on the Megasquirt.

With widebands that have a separate ground for sensor and heater however, that is the way to do it.

Hi I've upload the update afr gauges

Does this looks normal now? Sometime it drop down to 14.3range while the gauge is at 14.7-15 range,
Also one thing I've notice during startup is that the gauge in Tunerstudio is richer during warm up. After a while it will slowly catch up with my mtxl. Is it normal?
I feel like I should look into the setting in my mtxl hopefuly that would smooth out the aft output.

Thanks

Its still being erratic, which is weird.

You have a CAN module which makes a huge difference in the quality of the readings.

True, I didn't think of that.