stereo shop can't fix whine from engine

[chuyler1]

well if you have two amps and a cap and ground them all to different places...that can induce noise. You should always ground to the same point, even if it means using a distribution block for your grounds.

Some even swear by running a ground wire from the head unit back to the trunk where the amps are ground but I think going a bit overboard.

 

[porkcrackers]

muting plug results

So, I used 1st Mp3's advice and made some muting plugs exactly as shown/described. The result was no noise coming through the speakers with them in while the car was on. I just replaced all the rca's that were previously used for the system. You had mentioned if there is no noise then it "is bad rca's or at least the signal through them."

I am pretty sure the rca's are good. I will check them eventually if needed. If not them, what would cause the signal through them to induce the noise?

 

[1sty]

You have to do a continuity check on the RCAs to insure they are good. Anyhting else in the signal line could be suspect. You mentioned the installers tested some cables by running them through the car away from the power wire. So long as the RCAs are by the power wire they will generate noise. They must be moved. Run your own test set on the other side of the car and see what happens.
THe headunits ground could be the cuase but I doubt it. The amps ground could be the cuase aswell and is more likely. WHere is the amp grounded and is the paint scraped away?

 

[JeRNuT]

might be stupid, but make sure your defrost is not on at that effects my radio

 

[chuyler1]

If you ran the RCA plug test successfully, then the problem is probably not with the amp install...but with one of three things:

1) Bad RCAs
2) Bad RCA placement
3) Bad wiring of the head unit
4) Antenna

Option 3 can include the ground, as well as any other wires...dissconnect any wires you are not using from the harness (for example if you are not using rear speakers, clip the wires and cover them with electrical tape.) Make sure all wires not used are covered with electrical tape.

If something like the power-antenna-turn-on wire is roaming free inside your dash...all it has to do is touch bare metal to induce noise into your system.

Option 4 mostly occurs in older vehicles with bad wiring. If some other device in your car has a bad ground or a loose power cable that is touching bare metal, it could be making its way to the antenna, down the antenna cable, and into your head unit. You can get an antenna isolator to fix this. Pull the cable out and put in a CD to test whether the noise has gone away before buying one though.