engine noise with my polk C400.4 amp

[docsnead]

I installed a pioneer DEH-P5800MP head unit and put db6750 in the front doors of my 02 avalanche.

Next I bought a C400.4 Carbon Series 4/3/2 channel Amplifier. When I first put it in I was getting engine noise through the speakers. So I thought it was maybe the ground wire and I unbolted it and used gas to clean the undercoat of the chassis then used sand paper and rebolted the ground. That didn't work so I started checking the RCA wires and when I would unpluged the front speaker RCA cables the noise would stop so I switch rca cables and unplugged the cable I thought was bad. I proceeded to ajusted the amp using only db6750 in the front doors man did that sound loud and clear.

Today I put a new RCA cable on the rear speakers and Installed a brand new set of mmc6500 momo in the rear doors and when I went to test them my engine noise came back. Frustrated I put a jumper wire from the body ground to my chassis ground and that did not work either. If I unplug the rear RCA the noise goes away.

what should I do next ?
:confused:
Thanks in advance ,
Keith

[jcaut]

Hi and welcome to the Forum!

If you'll scroll down the page a little, you'll see a "Car Audio and Electronics" sub-forum. You'll have better luck if you post your question in there. It's mostly home-audio enthusiasts in this section.

Jason

[docsnead]

Thanks Jason.
Keith

[Eric Wong]

Try regrounding the headunit to a different location, particularly if only using the OEM ground on the factory harness.

[docsnead]

Ok Eric i will give a try.
Thanks

[docsnead]

Thanks everyone I rerouted rca's and it fix the problem.
Keith