When I first installed my AEM wideband about a year ago, I wired it in, following the instructions that accompanied the gauge. However, when I went out to log, the wideband data had excessive noise. Assume the noise was due to bad grounding; I moved the grounds around a few times, but it did not make a difference. The gauge still worked without problem, but the data it gave out during logging was almost unusable. In a final attempt to fix my logging issue, I followed the Innovate wideband wiring guide. Following the Innovate wiring guide fixed my logging issue instantly. I am not logging at about 40 samples per second without any of the previous noise. I put both logs into FC Tweak to see the quality rating assigned to both logs and was pleased to see it just from 1/9 up to 9/9. Due to these results, I would advise those having issues logging acceptable data with an AEM wideband to try the Innovate wiring style first. The wires go as followed:
Red - Switched 12v
Black - Ground
Brown - Ground
White - AN1
Ground AN2 to the same spot as the Brown wire with some higher gauge wire.

TL;DR: I improved data log quality on my AEM wideband with the wiring schematic above rather than the one AEM provides

 

I have wanted to ask before you run the Innovate wiring guide way of wiring, did you get the same reading on datalogit and on the aem gauge itself? I have read alot of post about this and have never got the gauge to agree with the datalogit screen reading at all. I am not talking about .1 or .2 off... strangely the datalogit reading is 2 points richer in most cases. Say the gauge read 14.7 the datalogit will read 12.X.... I have wired it as per instructions, played with the polynomial, used aem calibration figures... with no sucess. Will wiring an2 to the same ground as the gauge helps with this issue also you think?

thanks.

 

I have not run into that issue so I can not say for certain, but I do think it would be worth a try. Where are you currently grounding the gauge?

 

​​​​​​I had a mechanic install the gauge before. The gauge was powered from the cigarette lighter... And the an2 ground I split it to the dash bar... It was reading weird as I said.... Today I had the mechanic run the an2 ground to also the cigarette lighter... At idle it is 0.4-0.3 different between datalogit and gauge... Once given gas... It was 0.1-0.2 off.. I guess that kinda solved the problem as everyone is not getting exact reading between the two..