I just installed a new head unit with a metra wire harness and I am picking up engine noise on my speakers. I used the metra wire harness to plug into the factory harness. So instead of using the speaker outputs on the head unit I am using the RCA pre-out from the head unit. So I am still using the factory amp to power the speakers. I hooked up the ground wire from the head unit to the one provided by the factory wire harness. Whenever you accelerate you can hear it through the speakers. It is like a whining sound. Does anybody know how I can get rid of this problem?

-Adam-

 

I'm not sure what a metra wire harness is but I bet your problem is using the RCA-pre out. How shielded are your RCA cables? Higher quality ones might help.

What head unit did you go with? I'm still trying to find one that I like.

It might be the ground, too. Try a different ground other than the one you used.

Hope this helps...

 

I heard wrapping foil around the RCA cables will help reduce engine whine...