i have a problem, i just finished installing new h/u new rear speakers and new amp i hooked all amp wring kit up and playd fine but when u start car u get a interference in the speakers that are ran by the amp its loud and always there, but if car isnt running there is no interference. i dont get it can anyone help???

That is the interference from the Alternator.

Make sure you run the power cable on the opposite side of the car to the RCA cables. If the RCA and power cables need to cross, try to cross them perpendicularly.

If the cables are already running on either side of the car (ie. RCA along passenger side and power cable on drivers side), then your EARTH at the amp or head unit needs to be more secure and have a better connection. The ground cable for the amp should be short and be grounded somewhere near the amp. If the amp has a good ground contact, then it is the head units fault.

With the head unit, most brands can get away with using the existing ground cable from the stock unit. I have found that the Pioneer ones (and others may agree) have to have their own ground with much better contact then the stock ground cable. So to be safe, you can always create a new ground for the head unit separately, making sure contact is firm and good.

If after all that the problem still persists, it could be the RCA out of the head unit is buggered or the RCA Input of the amp is buggered.

I have now run out of ideas . Hopefully that helps.

phong =P~

What side of the car are the RCA cables ran on?

would that explain why when the car is running you get interference? Amp wiring is run along the drivers side.

they need to be run down the opposite side of the car to the power cable.