alternator whine

[taco]

Hey,
I just recently bought a 1987 5.0 LX and I was told by the owner that the radio tended to make noises at times. Well I didn't really mind not being able to listen to my radio at first, but now would like to try and fix it so I can listen to it. There's an aftermarket deck that has a CD player, speakers in the doors, and amp. I'm pretty sure that it's alternator whine because from what I read if the whine sound that it has increases and decreases with rpms then that's what it would be. It makes this whine when the radio is on and when a CD is in only when the engine is on, when it is off it sounds fine. I tryed unplugging the RCAs and listening for any sound and I heard none so I would imagine that the amp is grounded fine. From what I have read and understanded I need a noise filter/noise suppression kit. Wanted to get some input on this before I go and doing anything that I don't need to do. Any help would be great. Thanks in advance.

[xYoung347x]

Does your car have an antenna? Make sure its ground properly so the RFI will be low and if its damage trying getting a new one to see if it fix it. Good luck.

[highrev]

usually the suppressors for the whine connect to the rca jacks. I'm not sure if that will work in your case unless it is the amp. Are you saying that when you unplug the rca jacks for the amp you don't get the whine or you don't get any noise when the engine is off. If the amp looks like is grounded fine and the ground wire is not bigger than 2 ft then the suppressors will help minimizing the whine.

[taco]

The antenna looks fine but I can try checking out the ground for it. When the RCA cables are unhooked from the amp and the car is on I don't hear anything and from what I've read that's supposed to mean that the amp is grounded properly(not sure if this is right but it's what I've read). I found the ground for the amp and it is going through a plastic interior piece and then into metal, would this effect the ground at all? Should I have it going straight into the metal rather than through this first? The ground wire appears to be less than 2 feet long but I will double check tomorrow just to make sure.

[highrev]

it's the other way around. If the amp is disconnected and no radio noise them it's the amp. If the amp is disconnected and still get the noise then the raido still has a bad ground somewhere. They usally call this bad ground loop noise or something like that. Try to reground your wire from the amp and see if that works. I know this is fustrating. I had a somewhat similar prob with another car I have. but it was my dvd player in the car that had a ground problem. I got a noise suppressor and it helped. It didn't take all the noise away but it sounds way better than with out it. If the noise isn't that bad the suppressor may take most of you noise out, my dvd player was generating a loud ground noise thay is way I still hear a little.

[DatDude]

your RCA are ran too close to your constant 12 volt wire for the amp. if its not a shielded rca set it will pick up the noise. buy a good set of rcas or run the rcas and power on opposite sides of the car to the amp. id bet anything they are run right next to each other.....

[taco]

Ok thanks for clearing up that I had that backwards. I will try regrounding the amp and see if that fixes the problem. The power wire and the RCA are on opposite sides of the car. The power wire is on the driver's side and the RCA on the passenger's side.

[taco]

Problem solved. It was the ground for the amp.

[highrev]

Sweet now you can jam and not worry about the dam whine