Thread: ground for wideband when using nismotronic breakout box

I wired my AEM uego white wire to adc0 on the breakout box. The ecu seems to be reading AFRs but they are fluctuating much more than on the actual gauge in the car.
Today i tried running a wire from the black AEM wire to the ecu ground. After soldering this wire...the AEM gauge in the car doesnt show any readings at all, but the numbers on the ecu seem more consistent.

any idea what i did wrong..why would the AEM gauge stop working but still send data to the ecu?

i did not clip the black aem wire so it is still connected to its original ground source as well as the ecu ground..


thanks for any help you can give me!

Can you post a wiring schematic of the AEM unit. With the fluctuation, what you are seeing is the sampled value at a specified rate. Now the value you see on the gauge is a filtered value. What you are seeing on the ECU is also a filtered value, but by default the filter is turned all the way down. Change the filtering value in the ECU for the wideband. This will bring the numbers to a fairly consistent range as the gauge. I could never get the numbers to match exactly, but I trusted the ECU signal more than the gauge. However, if you find that the ECU value is off 1 or 2 points, you will need to do an offset correction so the ECU sees what the Gauge displays.

jtfc (jiggle the fucking cable) and use only 1 ground. clip or do whatever you need to do to achieve this.

^, ^^
thanks for your replies

I clipped the wire after the solder joint..gauge still isn't giving any numbers. i disconnected the ground from the aem to ecu and left the wire clipped..which i would assume meant it is not grounded...and the gauge works. havent tried logging with it like that though..

Just leave it how you had it before and follow my directions on setting the filter and offset.

filter is currently set at 4 and offset is -0.4..and the readings were fluctuating quite a bit
should i bump the filter to 7 and see what the readings look like?
until i get a somewhat steady number its hard for me to figure out how much voltage offset is needed

if you have closed loop on, turn off narrowband o2. it will bounce around like crazy when cruising due to the nature of a narrowband o2 sensor (if you are even using it)

7 may be a bit high, for my liking anyways. The filter is just creating a more linear average over time the higher in value you go. So going too high and you will lose out on some spikes or dips in the AFR that can help you during tuning. But too low a filter and its all over the place. 4 or 5 is plenty of filter. Also, what will help is to ground the AEM unit to the same location as the ADC box. So basically if your ADC is grounded at the fire wall near the ECU, run your AEM ground to the same post. OR to the sensor grounds on the engine, either is acceptable. ALSO what zeneffect said. I never ran in closed loop though.

i dont recall having to ground my adc box. i grounded my wideband to the metal that holds in the cup holder, stereo, heater controls, etc. i had a bad ground at first (it eventually became completely disconnected) and regrounded it to this location and its been working great. using an innovate mtx-l however. im not sure how your aem gauge even powers up with no ground present, you need to check your wiring, and use 1 solid ground, any ground and go from there. if you are 100% everything is wired correctly and your gauge doesnt display, replace the aem unit as something is broken.

how big is the swing in nismotronic? you can use fraps to record it then throw it on youtube. if its all over the place, start by checking the connection to adc0 and the rj45 cable connection on the adc and ecu end or maybe try switching it to adc1 to see if you get the same result.

thanks for the help
i didn't realize the breakout box had to be grounded
i will try setting the filter to 5 and trying some other ground locations

i will do a little more futzing tomorrow morning before i leave for the dyno tuner..


for the tuning i assume they will use an exhaust sniffer for afrs so they wouldn't need to log them via nismotronic..i hope


thanks again for your help!