Alternator whine!!!!!

[4Wheelin]

I had my box built over the weekend and had all the wires fixed up after my shotty install. I was hoping that it would get rid of the alternator whine because the previous ground wire was wayy too long and now it is shorter but it didn't. Could my alternator be going? I have no clue and it is really starting to bother me! Any help on this topic is GREATLY appreciated.

 

[leenjen]

if rewiring didnt fix the problem, maybe you should try a ground loop isolator. they're only like $10-15, and they usually work.

 

[4Wheelin]

Where can I get one of those? and Do you know how to test if my alternator is bad?

 

[leenjen]

wal-mart sells them. and i think radio shack does too.

 

[Mike 92 XLT]

You said that you shortened the ground wire, but did you actually move your ground to a different spot on the chassis (I'm assuming you did). Check where it is grounded and make sure that it is grounded to bare metal and not just to a painted part of the chassis. Also, how are your signal cables run? Are the power and ground wires near the RCAs and speaker wire? Try running the power and ground wires down one side of the car and the RCAs down the other side. If all that fails, try the ground loop isolators leenjen suggested. As for the alternator, most places like Autozone, Sears, etc. will test it for free while it's in the vehicle. Call around to a few shops until you find one that will do it, although I don't think that's your problem.

peace

Mike

 

[4Wheelin]

The power is ran on the drivers side of the car and the RCA's are ran on the other. I used the same ground point which was the bolt that holds the seat in. If that is the case where else can I ground it too?

 

[Mike 92 XLT]

Yup, first step is to move your grounding point. Try another bolt somewhere else in the car that is attached directly to the chassis. A different seat bolt could work, or there are plenty of places to attach the ground behind the trim panels in the cargo area. Good luck!

peace

Mike

 

[4Wheelin]

The noise is also loudest when I haven't driven my truck in a few days and when I start the car up you can hear the alternator whine under the hood before subs get turned on by the deck (it takes a second because the deck has to flip around and register itself before it can send signals out). I don't know if that helps but I am going to check the ground point and possibly change it.

 

[Mike 92 XLT]

So you hear the whine under the hood before your amp turns on? After your amp turns on, do you then hear it from the speakers as well as from under the hood? Maybe you should get your alternator tested first.

peace

Mike

 

[4Wheelin]

The louder the noise I hear from under the hood before everything turns on, the louder it is in the subs and vice versa. It is real hard to tell if it coming from the speakers and even if it is coming from there then I can't hear it, it is mostly the subs.

 

[Mike 92 XLT]

It looks like you have one amp for the subs and one amp for the door speakers, right? Since you can only hear the alternator whine out of the subs, let's concentrate on that amp only. Disconnect it entirely from the system and see what happens. Post back with your results. Be listening for both the underhood noise and also to see if you hear it out of the door speakers with the subs disconnected.

peace

Mike

 

[4Wheelin]

I'll try to do it later on today and I will let ya know. On my EQ there is a SUB button which can turn them on and off and I have turned them off while the whine was real loud and it continued to do so. I dont know if that has anything to do with it or not but it might help.

 

[zensius]

The 'alternator whine' might also be you fuel pump's doing. They are notorious for causing problems. There's a service bulletin for 91's -17-5 fuel pump noise filter kit E7PZ9B357A. Also check the wiring around your battery. If that's corroded or loose it can cause noise. Same with the alternator wiring.

 

[Mike 92 XLT]

Ah, good call Zensius, I didn't think of the fuel pump. A good way to tell if it's alternator whine is if it varies in pitch and intensity with the engine RPM. Usually though, you'll hear it from your tweeters. So let us know what you find and we'll go from there.

peace

Mike

 

[4Wheelin]

Pitch and whine definitly change when I accelarate but I dont hear it through the tweeters.

 

[zensius]

If you're only hearing it through you sub then I'd check the connections of that amp. Another problem is that cheaper equipment is more prone to be affected by the dreaded alternator whine. Another thing to think about is that adding equipment also makes all your components more suseptable (sp?) to the problem. Basically there's a million different possibilities you just have to find the one that's causing your problem.

 

[Mike 92 XLT]

Exactly. Your problem definitely sounds like alternator whine and it sounds like it is entering the system through the sub amp. For as cheap as they are, try putting a set of ground loop isolators on that amp and see if that cures it. Easier to do first before you try to rewire.

peace

Mike

 

[4Wheelin]

I am going to radio shack on friday and I will pick them up and try them out. I will let ya guys know how it turns out.

 

[4Wheelin]

Picked up the ground loop isolator today for $16 but it only has male plugs on it and the instructions say that it should be ran from the deck to the amp but can I a female to female connector and put it on the end of the RCA's that are ran from the deck and then plug it into the amp? Would this cause any kind of problems?

 

[leenjen]

yes you can use the connectors as long as you hook it up correctly.