nuisance whine coming from speakers

Seems to be more of a general issue, but is quite annoying. All of a sudden one day, I think I hit a bump in the road and since then a kind of whining sound comes out of every speaker. Its not real loud, and it only occurs when the engine is running. Also, the pitch changes with acceleration. If I turn the volumn up, its noise is mostly covered.
I've done most of the troubleshooting already. I swapped out the radio with another similar one. The only factory wires still being used are both positives, ground, and antenna. The amp is soley connected by RCA wires, and an amp remote wire is connected directly to the radio. All wires radio related have been checked for bad or grounded connections without it being fixed.
So to simplify, I have found an alternative way to connect each and every wire except the ground and positives. Could something somewhere in the car cause this to happen? Has anyone heard or had to fix this before?

Have you tried using a ground loop isolator? Goes from stereo to amp via the RCAs.

Did you run the RCA wires directly alongside the amp power wire? I had a problem with whining when I got my car, but it was because I had the remote turn-on connected directly to the battery. But if you ran the power wire near the RCAs, the RCAs will pick up some interference.

:werd:

It sure is tedious. I just see no reason why it only does this when the car is running. None of the wires are running next to each other unless it is a pair (left/right rca or +/- speaker). I have even disconnected all speakers and used a 4" mid speaker and also used a different amp. If I can't figure anything out soon, I think I am going to swap the entire system from my other eclipse then replace part at a time to test it. Could it some how be possible that electromagnetic interference or a bad ground somewhere else in the car flows through the radio when the car is running? I've never heard of that unless there is a faulty wire in the radio itself.

It could be a bad ground somewhere, but I'm betting on interference between the RCA and power cables.

Doesn' necesarily have to be the power cables for the amp. Even wires running to the fuel tank can give emi, how about this. If you have power windows, flicker the switch up and down while the car and audio are on. If its a draw then the speakers will sound even worse, if they do then sounds like you have a nasty draw somewhere.

Oh, are any of your wires melted together? (anything running under your carpet)

As normal with any car issues I come across, few are fixed on the first attempt. I've narrowed it down to something related to the engine. Since it only occurs when the engine is running. What parts in the car are switched on and increase with the engine? The obivious would be the coil packs and tachometer. What else? Also, what does the voltage normally stay at while running? I've heard 14.7v, but mine runs around 12-12.5. It has a new battery and the alternator has been swapped. I don't remember if the voltage has always been that low, but it was low even with the amp disconnected. What could cause this noise to start? I hit a bump and the noise started. Let's say if I were to take it to a shop to search for the problem, how much would just the diagnosis cost?

Check all of the engine grounds to make sure one didn't vibrate loose or something.

are you refering to the wires that connect directly to the engine, a sensor, or something that controls the engine? There are only two wires that connect directly to the engine from the frame. I would also like to point out, this started november 06. I have changed out the engine since then, and it still happens. How likely is it that a sensor or gauge is causing this? I didn't swap every part, just the ones on the engine itself. The wires are all the same.

I doubt its a gauge or sensor... +1 for a bad ground. I guessing something under the hood. Check all the grounds you can find. And the one for the amp.

Try disconnecting your remote turn-on for the amp and see if it goes away.

I have confirmed there are no loose grounds in the engine. Also, there are no issues with the speaker system. I took another battery and connected the amp and radio to it directly, started the car, no noise. I cannot find any melted wires. I pulled every fuse/relay I could, to see if any of them broke the circuit creating the sound. I am a couple of days away from swapping every sensor with my other eclipse. nothing obvious is helping. The only thing that would make sense is a wire voltage changes with the engine. I will bolt another ground wire to the block to see if it makes a change though. A bigger ground wire should pull more electric. Path of least resistance right?

Try what I said. Disconnect JUST the remote turn-on and see if it goes away. My bet is that it will.

done that, didnt work

Did you try the isolator?

maybe if I could figure out what that was

Its a pair of RCA wires with a big ass battery looking thing attached to to it, The RCAs go in one side and come out the other. Its a feride bead used to suppress interference. You can find them anywhere that sells stereos.

Try taking the main fuse for your amp out. My buddy had a simalar problem. If the whine stops when the amp is unhooked, then you found your problem. Mess with all the wires til you figure out what exactly is causing it. Seems like his wires going in the amp were crossed or something stupid, but I know you said yours started after hitting a bump...