pgmfi.org

Mtx-l in crome kepd jumping but gauge is stable.
15afr shows from 15-17 when on idlev when raising rpm is stable tryed to ground straight on battery everywhere.using shielded wire.12v aswell tryed everywhere.same issue.

Any idias?

Best to ground at the thermostat housing.

Added 3000uf electrolytic capacitor on 12v and gnd.
Added 0.10uf capacitor on d14 and gnd.sorted all.at idle now Flunctuation just 0.5v but
All other is good.as on gauge.doesn't care for me idle.

For innovate doesn't care where u will ground u will have noise.
Just capacitors will help to reduse noise.

I have a LC-1 with ZERO noise?

LC-1 has a power, ground and signal ground. All wired off the ecu power, ground and ecu signal ground. AFR is PERFECT between logworks and crome ALWAYS.

So you are saying MTX-L has noise regardless? Because it only has a power and ground.
Try power and ground from the ecu, thats where you are datalogging from and there should be ZERO ground loop then.

my mtx-l is also grounded to thermostat and I have fluctuation.
I reduced it a lot in Neptune by decreasing the refresh rate all the way down

while gauge is pretty stable

im taking voltage from underdash fuse box.


Coupe-r which therminals are you taking the power/ground from on the ecu?

For my LC-1
power A25 I think?
ground A26
signal ground D22
signal 02 D14

Zero offset, no fluctuation. PERFECT!


I have since bought a MTX-L and have found it's 0-5v is USELESS!
It fluctuates no matter how I wire it. Reason being it does not have a sensor ground. Everytime the 02 heater turns on, the voltage changes. Even with key on engine off.

Try flatlining the slope in gauge config and you will see the fluctuation.
Power and ground from ECU or direct from battery.

How can I add a sensor ground to the MTX-L??????

when I turn the ignition off to calibrate it fluctuates like crazy while the gauge stays solid

for example the gauge will show 14.5 and Neptune/crome will fluctuate between 13.5-15.5 constantly.
grounded at thermostat and 12 volt from battery.
im using direct serial with Neptune now its much better that way

Exactly, the gauge is HORRIBLE because it does not have a signal ground.

You will get less fluctuation from power and ground from ECU but the fluctuation is still there.

If you are using direct serial then it's fine. However crome does not have this, also if you want to log 0-5v signals into a demon for onboard logging it's an issue also.

can the ground be added manually?

I got the voltage calibrated pretty good actually from 0 to 3.7 and 10 afr to 17 afr in Neptune and crome but im using direct serial now because of the fluctuation

I have asked that exact question in this same forum.

Otherwise I'll open up the unit myself. But I bet i'll have to cut traces on circuit boards etc to achieve it. Even if possible I'm not sure....

Just an update
Got my fluctuation down to around 0.1volt which equals around 0.25-0.3AFR with how I have it scaled
(when ever the o2 heater turns on I get fluctuation)

It reduced when I made the wiring short as possible, basically because the grouns loop is worse with longer wires I think...

Still no way around it without a dedicated signal ground.

Maybe I'll try adding in a 1N4001 Diode on the power ground wire as hondata recommends in an old article.
https://www.hondata.com/techwidebandtuning.html

btw I belive the reason it fluctuates is because the ecu O2 circuit is not a simple voltage read
its an algorithm of some kind it downscales the voltage or something like that

that might be a reason for fluctuating

remember that stock sensor has specific update frequency and specific voltage output
if the update frequency is off it will fluctuate. and not fluctuate with usb port in neptune

why not get the power and ground from stock o2 plug?
it seems to be working ok for me
one harness that plug in directly to wideband

If possible, ground the sensor signal ground to both ecu signal grounds (SG1/SG2 on P28), because that usually removes the possible voltage offset, provided that WB controller makes use of this. My current power wiring for Ecotrons ALM-ADV goes from battery to thermostat housing with relay that takes control voltage from fuel pump voltage. If this is not possible, make sure that SG1/SG2 is grounded properly to chassis.

is the A26 ground better than A23 ground to connect the LC1 ground ?