So i have got the most god-awful engine noise in my system. I have grounded the head unit replaced my rca's with 150 Fosgates. they are all alone in the install. I have a kicker 250.2. Some Polk Momo components, 2 Alpine type R's and a Fosgate 800.2. This system has a cap everything. This is the second one I have put in this car and probably the tenth I have installed on my own.
The noise is not related to the engine. Because when I turn the car on, with the hood up, the fan that keeps the fuse box pressurized comes on. I think that it is the same whining noise the fan makes, any help would be great. I also installed ground loop isolators can't shake it.

 

Crostfire2,

The first thing to try is check your grounds.

(Are your RCA's wired down the same side as your power wires?) If so run them down other side.

If your Polk passive crossovers are installed near a computer or power wire you maybe be picking up radiated noise.

You may also have a bad rca.

Try not to get frustrated. If you think it is the fan pull the fan fuse and take a quick listen to the system.