Well I'm stumped on this one....I have read searched this topic and tried various ways to cure it, but I can't eliminate the engine noise im getting through my front speakers. My setup is D3 to a RF Punch120 amp which powers my RF 12" Sub....no problems here. The rear door speakers (factory) are powered staight from the D3. The problem lies with RF components in front...powered by a RF 260sd.
I get all sorts of feedback through the fronts only while engine is running, and the sounds varries with the rpms of the motor. I have my rcas on one side of the car and my power wire on the other...amps are all in the trunk. All amps are grounded to a central point in the trunk (trunk latch bolt). I've tried other grounding spots but this one seems to be best....both amps have their own ground wire straight to ground. I can reduce the feedback noise by lowering the gain on the amp, but i cannot eliminate it and i'd like to have the gain a little higher. As stated above, my sub have NO noise at all, just the front component set (6.5" in the door and a tweeter in the door).
I've also upgraded the ground wires from the neg battery post to chassis, and 2 from the engine to the chassis. I have tried to give as much info as possible here...anyone have any ideas or words of advise?