Air/fuel meter gauge dances with my stereo

[ratedZ]

Hey guys...just wanted to know if that is normal. My Autometer phantom gauge gives me the readings just fine but I've noticed that the light would flicker left to right with my music (I have an amp.) Same thing happens when I adjust my automatic mirrors or roll the windows up and down. There's only three wires to the gauge....one is hooked up to the o2 sensor and the other is hooked up to the ignition that comes on when you turn the key. The other wire is grounded to the body.

[TimZ]

You are experiencing what is known as a "ground loop". Basically, the ground voltage varies depending on where you pick it up.

 

You are apparently picking up your ground from a place on the chassis/harness that is in the current path of your amplifier and mirrors. When the amp or mirrors draw current, they change the voltage at your ground. Since the ground voltage at the sensor is not changing (at least not in the same way), your reading flickers.

 

Ground your meter to the engine block as close to the sensor as you can, and this problem should go away.

[Kevin Shasteen]

And, if you haven't already, make sure your stereo receiver, amp & any other stereo component that has a ground wire are all grounded as close to each other's ground as possible! This will keep their signals & grounds as clean/undiluded as well.

 

I grounded my stereo & amp on the passenger seat support brace on the floor board next to the relay; havent had a problem.

 

Kevin,

(Yea,Still an Inliner)

[ratedZ]

Thanks guys! As for my stereo and amp, that's exactly where mine is grounded