Alt whine

[IrvJr]

Can anyone help me rid my car of the dreaded alternator whine? I have tried filters and new grounds. What should i try next?

Scott

 

[GNandTTA]

Need more info. What kind of radio, amps? Did you run the RCA plugs and power wire down the same side of the car?

 

[IrvJr]

Pioneer DEH 1000. 1 Coustic 360 for the sub, and 2 Coustic 160 for the 5.25 and 4 x 10's. Power and RCA go down seperate sides of the car, but go into the same access hole to the trunk. Should i shield it? After i ran a 4 ga ground from the secondary negative battery term, it seemed to go away for awhile but came back again. It seems everything i try works for a little while.

Scott

 

[GNandTTA]

Need to isolate what is causing the problem: radio, amps,. etc. 15 years ago a filter may have helped but today most radios have adequate filtering. Especially Pioneer, they make solid radios. Get a boom box that has a RCA input on it. Mke sure you use AC power or batteries to power the boom box. By using the boom box as the amplifier you break the reference to ground. It allows you to pinpoint the problem. Connect the output of the radio to the input on the boom box. Get a pair of headphones. Make sure the car radio volume is all the way down. Turn the volume up all the way on the boom box, turn the car on, put on the headphones and listen. If the noise is being caused by the radio or RCA wires it will be present through the boom box. If the noise is present, then run an exta pair of RCA's outside the car from the radio to the boom box. Still have noise? If you do then it is the radio, or the radio is picking up EMR. If the noise goes away, the RCA's are picking up EMR and must be moved. Let us know what you find.

If you determine that the noise is in the radio, try disconnecting the FM antenna lead. Sometimes you can get a ground loop from that.

 

[mcss383]

Originally posted by IrvJr
Should i shield it?
Scott

Only way to do that would be to put a thick piece of steel between them and with about a 99.9% certainty thats not the problem, and rarely is the problem (power and rca being next to each other).

Go through a systematic approach like what GNandTTA listed, its the only way to find and isolate the problem.

 

[IrvJr]

I dont have a boom box with RCA's. So i turned the radio off with the car running and the whine was still there. So then i disconnected the RCA input to the electronic cross over and then the noise went away. So, does that mean its NOT the radio or the amps? And more than likely the RCA near the power wires?

Scott

 

[GNandTTA]

So i turned the radio off with the car running and the whine was still there

So I assume you jumped the power antenna wire so the crossover and amp(s) were still running?

So then i disconnected the RCA input to the electronic cross over and then the noise went away

Very important - where did you disconnect the RCA's - at the radio or at the crossover? Reason being, if you disconnected the RCA's at the radio then the RCA's could still be picking up EMR somewhere between the crossover and the radio.

Also, what brand crossover? It pays to get a good brand here because it is absolutely vital to have a good switching power supply and a very high input impedance.

 

[IrvJr]

I did not jump the power antenna. My amps run off the ignition not the radio. So the amps were on.

I disconnected the RCA from the input to the cross over in the trunk. Its a Rockford Fosgate crossover.

Scott

 

[IrvJr]

Sorry its a MTX crossover, with low and high outputs.

Scott

 

[Turbo Dog]

I also get the alternator whine with the radio on. It goes away with the radio off. My RCA cables run down the pass. side, to the amps in the trunk. the power wire from the amps run down the drivers side, to the battery. If the rca cables from the radio to the amps are picking up the whine, what options do I have? Can I run the cables along the bottom (outside) of the car? Should I try grounding the head unit with thicker wire?

 

[David65]

Alternator whine can be a real pain sometimes. Here's what I've done on the different vehicles I've put systems in. I ran a large (#6 or #8) wire from the battery to the rear for both the positive and negative. Used terminal strips there to connect together the + and - wires for all the different components. This included running a #18 + and - wire back to the dash for the head unit and EQ. To get the ignition turn on signal for the head unit I used a 30A relay, controlled by the ignition switch, to then switch the + to the ignition lead going into the head unit. This eliminated any connection to the factory wiring to help get rid of noise. I run the rca's right beside the power cables and have never had a problem. I think the key is to not ground the different components at different points. I've done this on a MCSS & 3 different Blazers I've had as well as the GN and have never heard any alternator whine. Turn the volume all the way down and no noise at all. A friend who had a Z-28 came over a while back and had a bunch of alternator whine. Ungrounded the amp in the rear and ran a ground wire to the battery instead and the whine disappeared.

Yeah it's a bit of work and probably overkill, but I had the time and the stuff was just laying around.


David

 

[Turbo Dog]

Dave, you're a genious! I ran the ground wire from my amps to the battery and the whine is 99% gone. Can't hear it at all if I turn the music up just a tiny bit. It is just barely there with the volume all the way down. Thanks a lot! Now i can drive to the GS Nats with tunes, not noise (of course that also depends on what my girl friend is talking about at the moment).

 

[GNandTTA]

Your better off fixing the ground problem with the body of the car. You should not have to run ground wires through the car. You could probably fix your problem if you run extra small length ground wires from the battery to the frame and then ground the trunk area to the frame. Let the large frame rail be your ground bus. If your ground is that bad in the trunk it is probably affecting your fuel pump volume as well since the pump is grounded there.

 

[Turbo Dog]

I bought a Walbro and hot wire kit from Racetronix. It came with a short ground lead, which I ran from the battery to the closest nut on the wheel well. Apparently that didn't help the alt. whine though. Not sure what condition the Walbro is in, as a mechanic installed it for me. Car runs good, though.

 

[GNandTTA]

It came with a short ground lead, which I ran from the battery to the closest nut on the wheel well.

That connection needs to be upgraded as well .What I'm taliking about is run a 4g wire from the battery post directly to the pass. side frame rail. On the bumper support there are 4 big bolts. Make your connection there. Crank the sh*t out of the bolt. Then in the trunk run a 4g wire from the trunk body to the frame. There is a existing pair of holes right where the exhaust exits. Make the connection there. Again, big bolt and big wrench. That is about as good a ground system as you can get.

 

[Slowhawk]

I had the dreaded whine till today
Here's what I did:
Replaced end on ground wire going to Turbo bracket(motor)
Added 4gauge from battery to frame.
added 10gauge ground from Alt to frame.

The whine got so bad that I didn't use the radio.
Now it is dead quiet.

 

[IrvJr]

I have the dual post battery. So i took the extra neg post on top and added a 4ga ground to the inner fender well. It seemed to solve my problem so far.

Scott