Persistent Engine Noise

Since my last post on this subject, I've done several things:

Because the factory power cable from the alt to the battery ran straight through the middle of the car, I ran a new 4 gauge cable shielded in water tight conduit underneath the car, secured to the chassis. This goes from the battery to the alt. That didnt do anything. I found some succes though when I ran the RCAs through the headliner to the processors under the passenger seat (from processor, up the passenger side, through headliner to the rear deck to the amp). That helped some but not alot.

Working off that idea though, I pulled everything out and ran new cables along the drivers side through the head liner from the back of the Clarion radio to the rear corner of the trunk. That made a significant difference. The cables were by KnuKonceptz, of their Krystal Kable line. In the rear corner of the trunk, I installed an AudioControl EQQ and ESP3, as well as my Clarion SRK5 center channel amp and kept all the cables central to that location. There was no change in the noise with the addition of the equipment, or at least nothing that was extreme. Now, it is extremely faint and at times, nonexistent. Everything is run through the headliner and that was the only way I could elminate 98% to 99% of it.

During this process too, I upgraded all my wiring to the amps: 1/0 to a distribution block both for power and ground, and then 4 gauge power and ground from the blocks to the amps. No run is over 6 feet and the connections are made directly at the battery. The processors and the head unit, as well as the 12v factory outlet that my mp3 player's charger plugs into are all wired through this system as well, eliminating as much of the factory wiring as I could. This has to be the hardest car I've ever worked on.  I'm sure there are some out there who think that either I'm exagerating or that I dont know what I'm doing but I'm telling ya--this sucker was a tough one to beat... and I'm still not entirely done.

In the meantime, thanks to everyone who took time to read and respond. If anything new develops, I will post.

I'm still fighting the whine-noise issue in this 07 Saturn Ion. I've gone back and re-troubleshot everything in the system a couple of times since the last post and one thing I noticed that I may have over looked last time (or knew and forgot to post?) is that with the RCA's discconected from the PG Octane amp on the mids/highs, there is still a whine present. Also, the noise gets louder as the gains are turned up. Right now, I have reconnected all the additional parts of the system back in as there wasnt any change in anything with the other components left out. I have the amp virtually all the way down now and am using the adjustable input and output gains on the AudioControl EQQ to "adjust" the output level. Doing this minimizes the noise to some extent. Meanwhile, the amp is still grounded directly to the battery (the battery in this car is located in the trunk), and I just came in from running 1/0 from the negative of the battery to the alternator chassis and then ran from the alt. chassis to the frame of the car, just to secure the ground. There didn't seem to be any change in the noise.

To recap, the components in the car are:

Clarion DXZ665MP

So far, I have…

Swapped HU’s

Nothing has worked.

that pretty much sums up the previous four or five pages of this post. Does anyone have any other suggestions?

Have we tried removing the AudioControl pieces from the signal path?    These 3 or 4 sets of patch cords you replaced, were they all the same brand.  As sedate said in the first response to this problem, I to am a big believer in the cheapest RCA cables are usually the most reliable and longest lasting.

yes. I've removed everything multiple times. Today alone, I had only the amp powered on with no RCA's attached and still had noise. I've run RCA's from the amp to alternate sources (like another cd player or my mp3 player) with no luck, even running the signal outside the car, over seats, etc. The only progress I made was running the RCA's through the headliner by going from the HU, up the drivers side pillar, through the headliner, down rear drivers side pillar and to the amp which is mounted on the underside of the rear deck (and it's not touching metal at all but mounted on a vinyl covered MDF amp rack). Yeah... I started off with the easy things like that way in the beginning before I ever posted this. I wish it was something that simple.

I was thinking back to something DYohn mentioned about measuring the resistence and I may have overlooked a measurement. In measuring return resistence, is that from the positive side of the amp back to the positive post of the battery? I didnt measure that, if it was. I just measured from negative point at the amp to the negative terminal at the battery and since everything is directly connected to the battery, it was a very, very low impedence.

I've been trying to think of where a ground loop would be but I cant imagine anything anywhere since everything is getting its negative and positive directly from the battery and now directly from the alternator too (alt to batt to amp)

I disconnected the speaker wires from the amp and tested continuity with the ground at the battery but I did not discover anything ground... no resistence read at all on anything. When I did this, I forgot to check the AC voltage and I wont have my car until Wednesday at the earliest--the hood is getting repainted due to rust under the paint (yes, its a new vehicle with rust on it... all under warranty). I will check the AC voltage then. In regard to that check, am I to check at the amp or at the battery or at the alternator?

I just had a thought: do you think that having the battery in the trunk is what could be causing the noise?  In the very beginning of this system, long before I got the bass or even used the Phoenix Gold amp, I went first with a Rockford Fosgate 4channel. It was installed well, directly wired to the battery and had noise. It was a used amp and was given to me so I thought maybe it was at fault. Since then, I've realized that it wasnt. Oddly enough, even before I did a system in the car, I had a horrible noise with my mp3 player connected to the factory radio through an 1/8inch audio connection. I never understood why there was noise and it seemed to only be present when the charger for the mp3 player was plugged in, and only heard when connected to the factory system (if you used headphones on the mp3 player with the charger plugged in, there wasn't any noise that I recall).

Sorry if I misled you: there is only one battery in the car. Saturn puts the battery in the trunk on the passenger side and runs a 6 gauge cable through the car to the driver's side firewall, going through and then across the front of the engine compartment to connect to the alternator on the passenger side of the engine compartment. I wish so much that the battery was up front like it is on other vehicles. Though it may be completely and utterly unrelated, in my mind, I'm thinking it has a lot to do with it all. I will check the AC voltage at the battery in the trunk on Wednesday and post the results. What's your theory on this? What are we looking for or not looking for with this check?

In regard to that 6 gauge factory cable I just mentioned: I originally thought that all that cabling going through the car was causing interference, especially since the intensity of the noise would change as i moved the RCA cables further and further away from the floor of the vehicle where the cable was located. As a result of this idea, I took out the factory 6 gauge wire and ran a length of 4 gauge OFC cable (better quality than the factory) straight down the passenger side, underneath the car, from the battery to the alternator. This didnt change anything. As of Sunday evening, there is now a ground cable run parallel to my 4 gauge power cable going underneath the car on the passenger side from the battery to the alternator.