alternator noise

Hey everyone!! new to the forums and had a quick question about a problem I have been having.  I have looked around a bit anc can not seem to find the same problem i am having.  I have just changed around my stereo equiptment as the previous stuff was stolen.  I have a 97 Cavalier running Pioneer DEH-P840MP.  The Headunit is controlling and powering my front speakers, 2 6 inch and 2 tweeters in the front running off crossovers.  I have RCS's going from the HU to an MTX RT4180X power a 10 inch Sub and 2 Rockford Fosgate 6x9's in the back.   Periodically seems to be more when I first start the car, I will get the alternator whine but not every time.  Sometimes it is very bad and other times it is hardly noticable.  If I shut the deck off and leave it for a fwe minutes and try again or even just turn it on and off a few times I can get it to go away, gone completly.  I had this problem before with an Alpine 7893 but then it just went away on its own and I did not worry about it.  I have not had this problem for awhile and was running this deck for probably 2 weeks with no problems.  Started up again this morning, only thing that I have changed in the last 24 hours was I did a bunch of work to bolt the sub down and pad lock it in so it does not get stolen again but other then that I have not changed anything.  I did extend my sub wires a little bit as where the wiring plugs in to the sub my previous iwring was just a little to short, but I dont see how adding a little bit more wire would cause it, in fact I am sure it has nothing to do with it....The amp is grounded with 8 gauge I belive and is only running like at most 2 feet.

Before you spend a lot of time trying to figure this out.  Pioneer decks are famous for losing the ground reference on their RCA jacks.     Take a short length of wire, ground it to wherever your radio is grounded.  Strip the other end and touch it to the outer part of your RCA cable.  Touch it to the shiny metal part that you can see when it is plugged in.  This should make a pop and the noise should go away.  Let us know if this works and we can tell you how to fix it.

Before I pull apart the dash to get at the deck again, would the problem pop up randomly with this pioneer problem? I find it strange that it would just go away.  I can see if it stayed on. 

mogrules wrote:

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Before I pull apart the dash to get at the deck again, would the problem pop up randomly with this pioneer problem? I find it strange that it would just go away.  I can see if it stayed on. 

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It could be a faulty connection on the aformentioned RCA ground inside the amp. This might be why it happens sometimes -maybe with bumps.

I think you can try this at the amp side. I personally don't see the point in removing the HU to try it there, I know it's a pain to have to remove the entire dash pad and gauge trim panel just to remove the HU on 95+ Cavaliers (I own a 95).

Also, do you have power/ground wiring of sufficient size for both the HU and amp(s)?

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2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001

found it....the amp is quite a few years old, I have had it the whole time and I guess the crossover switch is getting old.  When I move the switch back and forth the interference comes and goes.  If I turn the crossovers off completly to the 6x9's is stops and does not come back, so I guess I am not going to use that crossover any more.  Thanx for your help though!