First off the system, Pioneer Deh-7500, Cdt components running off a Kenwood Kac 8401 and two rf he2 12s running off an old pioneer, power (4awg into a dist block to 2 8awg) and signals are run on opposite sides of the car. Ive tried regrounding in several spots, ground loop isolator on the rcas, upgraded the rcas, power line filter on both the kenwood amp and the headunit, and basically everything else i could think of. I have not yet done the big 3 but am looking into it. My problem is that i have your classic engine noise- follows pace with rpm, real annoying etc. What i was wondering is what do i do from here will the "big 3" help? what about a new battery? new spark plugs or an alternator? Im not really trying to break the bank here but i have what i feel to be a very nice system for my tastes which i would like to listen to while i drive. Anyhelp would be greatly appreciated.

 

sounds like alternator whine, is the while comming from the speakers or from under the hood?

Did you get your free anternator from the 97 recall? mine wined when it went bad

 

sounds like alternator whine, so spark plugs and spark plug wires arent the issue.

i know you re-grounded tha amps, but did you re-ground the head unit?

has this always been a problem or did it happen recently?

 

Yeah, check the wires up front by the head unit. Noise can be introduced from there too.

 

this problem has been happening since i added the kenwood amp. imma check out the wires by the hu. <just tried that no help would grounding the hu with the amps help at all u think? btw when i pop my hood there is a loud clicking noise which i think may be the alt, is it possible its no good? it was replaced under the recall about 2 years ago or is it possible for whatever reason the amp is no good? im out of ideas....this is probably the most annoying thing ever

 

I had a killer alternator whine that wouldn't go away. I found the best way to troubleshoot was to do it in a systematic manner (to isolate exactly where the problem is) instead of bouncing all around hoping to get lucky and solve it. Here's the steps that were recommended to me and I followed.

Obviously, start by making sure ALL grounds are securely fastened with plenty of connection area. Make sure paint is well scratched off of any surfaces used for grounding so wire/ground is making good contact with bare metal. Consider trying a few different grounding spots. Ground runs should be as short as possible with large guage wire and all amps should be grounded together. RCA's should be kept as far from power wire runs as possible (run on opposite ends of the car usually)and if they MUST intersect, make it at a total 90 degree angle so theres as little interference as possible.

Still got the wine? Make a muting plug...simple

http://www.davidnavone.com/richardclark/mute1.jpg

Unplug RCA's going into amp and put in muting plug. turn on car and stereo. Is the nasty whine still there? If so, you now know it's coming from your amps or speaker connects or something...most likely amp. Try another amp or keep playing with grounds. Usually though, it will go away and you'll find the problem lied elsewhere...read on..

Did the alternator whine go away? If it did, you now know it lies "earlier" in the signal path of the system.

The next step, then, is to find out if it is the RCA's themselves (common problem) or the RCA's getting interference from power wire. To isolate this, get some Male to Male RCA couplers
http://www.radioshack.com/product.as...5Fid=274%2D873

Take out your head unit (yes, this part is a Pain in the butt), temporarily wire it up right in the back of the car with your amp(s) (you should already have the necessary wires back there for your amp), and connect the HU to the amp with the coupler (basically, the head unit is right next to or sitting on top of the amp) making sure power wires are still out of the way and the HU is grounded right there with the amp and with a short power wire run.

Turn on car and radio. Did the whine go away? If yes, then it was bad RCA's (then try buying some new RCA cables and seeing if theres a difference), an RCA run that picked up noise from some power source (rerun RCA's a different place in car), or your HU's grounding (play with new grounding points).

If it's still there, its your HU. If it's the head unit, you can try to replace the noise filter (actually, to be honest, i don't think it's a noise filter, but most or all HU's have them...a little 2 inch by 1.5 inch electromagnetic looking thingy in the back of your HU) with a new one from Rat shack or try a new HU.

If you've done all this to no avail, then I'd recommend going on carsound and asking Dave Navonne in the troubleshooting forum. Your problem is far out of my reach. I think he also sells "special" RCA's that he made to not pick up noise...though most RCA's will be ok usually.

If you follow these steps, you can diagnose and solve an alternator whine problem prolly 99% of the time.

Good luck and hope this helps. Let us know how it turns out.

 

some people might be wondering what good does shorting the RCA plugs do...so here goes:

the reason the RCA's are shorted is to force the input voltage to be zero volts....since the input is zero there should be nothing amplified in the amp..so if there is still alternator whine, then the problem is an internal amp problem. just to bring people up to speed on the "why" portion.

 

update, i removed all the crap (filters, isolators etc) and regrounded the HU with the amps by running a wire into my distro blocks so that all of my system components are grounded in the same place this helped significantly, i then messed with the rcas and found that i could completely get rid of the noise by pulling the terminal out just a little(why i dont know but it works)

cliff notes: messed with rcas regrounded everything, now it all works and my lights dont seem to dim anymore at all!

thanks for all the help guys
- RaGa

 

In that case it sounds like both a bad ground at the headunit and a bad RCA cable. What kind of cable are you using, shielded, or twisted pair?