ok, so me and a buddy decided we were going to build a custom fiberglass system in my truck for the newly bought evo.. all is going well until we decide to actually plug in the RCA's into the speaker amp only to be met with a horrid loud ringing through the speakers.. I have wired this car up and down, left and right, every which way to try and get this to stop.. it seems to be when i plug in the sensor to the gauge itself that is connected to the o2 sensor and then the noise starts through the speakers.. i have heard of ground loop isolators and things but not sure if they will work for this problem.. if anyone has ever had this happen or know what could fix this, please throw me a bone.

 

Is this with the engine off? Disconnect all the leads from the four channel amp, then connect one at a time and see if it does it individually, maybe you can narrow it down to a shorted speaker lead somewhere. I ran into something similar where a tweeter was grounded but caused all sorts of high pitched noise through all speakers, narrowed it down to the shorted tweeter. Where does the ground for the aem piece ground to? perhaps it's shorted to a speaker lead, but doesn't throw ground to the lead until plugged in

 

i have the same problem too with my ssl stock speakers going through my avic z1. mines is not really to loud though so i just live with it.

 

Sounds like a bad ground loop, or too much draw for the UEGO tapped from the same circuit the radio is on. Try a different [better] power source for the UEGO. I have mine sourced on a fuse tap in the glove box and all is well.

 

i would use mini add a circuit for all the aftermarket gauges

 

That is what I was thinking also. If hes running the Uego off the same power/ground as the stereo, you will get noise and/or interferance.

 

I would hope after a year and a half that he would have fixed the problem by now

 

I have this same problem but they're already on different circuits.

 

I know I'm bringing this back up from the dead, but I'm posting a solution for anyone that happens to come across this and has the issue. The solution is to add a 25V 2200 uF capacitor to jump the power and ground wires for the AEM UEGO gauge. This will filter out the interference noise. I found some information on the Miata forums and with the help of a co-worker figured out the solution.

AEM tech said they have no reports of this issue, but if you Google AEM ringing/AEM radio interference/Wideband interference, the threads go back over a decade. I upgraded my stereo, wiring, and added amps and noticed the noise. With my stock system, I had a very slight ringing with key on radio off. I always thought it was normal. I finally got so annoyed I traced it down and realized if the wideband was either off, or the o2 sensor pigtail wasn't plugged into the gauge, it wouldn't make the noise. Turns out the heating elements dump about 1amp out of the ground which is more than enough to cause electrical interference. Some people can't hear it, and some can. Adding more grounds, shaving off paint, wiring directly to the battery, etc didn't resolve this for me. Some say it does, but not for me. I rewired everything, and it wouldn't go away. Adding the capacior to "jump" the power and ground worked. Just strip back a little bit of the insulation for the power and ground, and solder the capacitor in place. I'll attach a crude test picture I took before cleaning it up and heat shrinking it also.

 

thanks for that!!
I had same issue about 5 years ago - i sent an email to AEM reporting that and asking for their advice. They never answered. So i think they just choose to ignore it.
i recall i tried adding the capacitor ( tried several values and sizes) on the supply to the gauge. Nothing helped. I ended removing the aem gauge from the car.