Strange Intermediate Alternator Whine!

[MeridianBlade]

Hi All!

So here's one I couldn't find an explanation for on the internet (only constant alternator whine, not this on off stuff).

I have a alternator whine that literally comes and goes... If i click the door unlock/lock or click the wind button on the windows up and down a few times, I hear a short pop and the noise goes away, sometimes for a few minutes or sometimes a few hours. Sometimes that little trick wont work at all and I just turn the radio off in frustration. It goes up and down with the RPMs and can only be heard when the truck is turned on. The most frustrating part of this is how random it is. Sometimes the whine is LOUD, sometimes its very soft... and sometimes I'll take a hour drive somewhere and not hear it once. Here's the thing... this just started happening out of no where, my system worked perfectly fine and I didn't have any whine for a good 7 or 8 months, then all of the sudden I turn the truck on one day and I get the whine.

My RCAs are run opposite from my power. I JUST replaced a Sony Explode head-unit with the 9887 (sick deck btw) and im tying into the stock harness ground.

My two amps are connected at a Y to a hole I drilled a year ago into the bottom of the floor... at the time I used a angle grinder to clean off the paint. the connection does look slightly corroded.. How copper would look with a little moisture after a year. I just dont understand how that would cause a intermediate problem.. ANY help would be great!

Here's the system if this will help:

2002 Ford Ranger XLT

Alpine 9887 + Imprint System + High Speed Ipod connection to 120g ipod.

Mids/High

California 4ch 700w

4 Infinity Kappas 6 x 9 2-way

Lows

Lanzar 2ch 1000w

2 Kicker Comp VR 12's

Rockford Fosgate 2 Farad Cap - Y split to both amps.

Click to read more...

 

[audioarsonal 10+ year member]

Sounds like a load issue.Either you don't have enough amperage or something could be failing.Have you had your battery tested or charged recently?If the battery is bad it could be putting a strain on the alt causing the intermitent squeal.

 

[Upzaw2000]

very strange, i wuld have to agree that something is failing.... but idk... have to think about it more

 

[iamamp3pimp 5,000+ posts]

what speakers does it come out of?

 

[MeridianBlade]

It comes out of all 4 speakers, I can't hear it out of the subs...

 

[MeridianBlade]

The digital readout on the cap displays 12.5 to 14.5 depending on the music.. if I recall correctly... I can take a look at that again if it would be of help..

 

[audioarsonal 10+ year member]

That just means the alt is charging.You need to have the battery load tested to see if its bad.

 

[MeridianBlade]

Where can I get that done? The battery doesn't hold a charge very well I know that. If I play my system with the car turned off, it dies in about 10 minutes..

 

[audioarsonal 10+ year member]

Where can I get that done? The battery doesn't hold a charge very well I know that. If I play my system with the car turned off, it dies in about 10 minutes..

That's not good!You should be able to listen to it for a couple hours with moderate play.

Go to Autozone or Advance auto and have them check it for you it should be free of charge.I would just get a new battery if you haven't replaced the old one in the last 2-3 years.

 

[MeridianBlade]

Here's the update:

The battery was reading 8 in one cell in 7 in another with 12 in the other cells, so I got a Red top Duralast and had that replaced. I also got my alternator tested after the battery was put in and it was reading 74.5 instead of 95.. the test came back as diode failed, so it's shot.

I'll be installing a new one friday morning, do you think that this was the problem?

The whine is now constant and messing with the doors will not fix it, So im guessing the battery was atleast part of the problem...

 

[audioarsonal 10+ year member]

Here's the update:
The battery was reading 8 in one cell in 7 in another with 12 in the other cells, so I got a Red top Duralast and had that replaced. I also got my alternator tested after the battery was put in and it was reading 74.5 instead of 95.. the test came back as diode failed, so it's shot.

I'll be installing a new one friday morning, do you think that this was the problem?

The whine is now constant and messing with the doors will not fix it, So im guessing the battery was atleast part of the problem...

I'm not sure where you got this from.Each cell is 2v.Series them all together and you get the 12.xx volts.Anyway it sounds like it was the battery and maybe it caused the alt to go??

Also what is the 74.5 is that the out amperage of the alt?Is this an High output alt or factory?

 

[MeridianBlade]

Hummm, im not sure, the numbers must not of been in volts then, but those were the numbers that he said came up for each cell with the machine he was using, either way the battery was definitely shot.

The factory amp should be putting out 95 amps, and its the original with 110k miles on it, and its putting out 74.5 he said when he tested it. So do you think this and the "failed diode" msg could be the cause of the whine?

One thing I did do, was while the engine was running, i pulled the RCA's out of the 4ch amp and the whine went away... I read that rules the amp out of being a possible cause.. is that right?

Blah, here I have a brand new 9887 with the imprint kit sitting on my bed and I can't even listen to it :-(