Originally Posted by Now534
What do you have for a deck? Pioneers (i know some older models do this not sure on the newer models) have a Pico Fuse internally that when it blows will create engine noise through the RCA's. Easy solution to this was to wrap a wire around the plug on the RCA out (then plug the rca in to the back of the radio) then take the other side of the wire and wrap it around a screw in the back of the radio (pick one there are a few).
Yep that was it I took and old set of RCAs and stripped the wire back for the out shield and grounded on another set of the RCA outputs(I have three) and it worked like a charm. Thanks for all the help guys!