I have been checking out the AEM forum for a while now, and would like some feedback from evom people about this.

I am wanting to know where others have grounded the O2 sensor ground to? The manual says to ground it to the O2 sensor ground per the ecu pinout. Some EMS owners say to ground it to a chassis ground along with the O2 controller power ground. The last one I heard today, and from a very well known AEM tuner, is to leave the O2 sensor ground "floating".

On the AEM forum one person mentioned that they were having different readings between what the lamda readings were per the EMS and the digital readout when having the 2 ground wires grounded together on the chassis. The differences would change based on things turned on and off in the car. They mentioned that the difference was very minimal.

Have not seen anyone wire it up to the O2 sensor ground per the ecu pinout, don't know what will happen. I don't plan on wiring it up this way, has anyone done it this way on a evo?

I have not heard any feedback from anyone leaving the O2 sensor ground "floating" if they have any issues with this. Has anyone here done this and what are your results?

 

You would be better off asking these questions on the forums dedicated for the EMS. I think you are doing yourselves a disservice by having a separate forum for EMS issues here, since there are no EMS engineers here, and few knowledgeable EMS users to answer questions.

http://forums.aempower.com/bbs


To answer your question though, run the 2 grounds to the same spot on the chassis. If you leave a ground floating, well that is usually bad. If you connect the two grounds to different spots you will create a ground loop and cause a voltage differential.