Car Stereo Problem

[willcheung]

I drive a 95 240sx base model. I got a sony HKDM cd, mp3, vcd deck, and a 7" in dash lcd screen, and pioneer 4ch amp for mids and highs, kenwood 2ch for subs and running a Cap. The problem that i encounter are:

1. the lcd screen always have lines going up and down while the engine is running especailly when i rev it, the line since to follow the rev. sometime the lines is worst.

2. encounter speakers making turbo like winding sound especailly rev up, only happen sometimes.

3. When i turn on my headlight (i have HID), fog light (SE fogs), and blasting my sound, sometime the deck, lcd, subs, and radal detector that is plug in to the cigarette lighter outlet will surge (turn off then on).

So is that means the alternator is bad, battery is bad, bad ground, RCA for my LCD and Sound need to be Sheilded or my cap is bad? how to test out the problems.

[Ritz S14]

3. Your lights dimm/surge cause your amps are pulling more power/amerage than your alternator can put out.. This puts a huge amount of stress on your amp and yoru battery, cause they're working MUCH more harder than they were designed to do. First thing I would do when you run a heavy system is to upgrade your battery to at least a Yellow Top optima, and remove your caps. The yellow optimas can somewhat function as a cap, since they are about 800cold cranking amps. I had a blue top marine deep cycle capable of 1000CCAs..my lights never dimmed... (I Had a MTX81000D running 1000watts RMS with 2 JL 12" W6 in my previous car).. If that doens't work, get a higher output alternator.

2. Make sure you run your RCAs and Positive cable at least 6" apart, better yet run them on seperate sides under the door sills.. Sometimes you may need noise filters.

1. I'm not totally sure, but once again keep your RCAs away from your power cables, and find some filters.. The noise is comming from the alternator..

I'm not a cap fan.. I had a 2farad cap, and it did crap for me.. it had a built in volt meter which was kinda cool..

[SlowCoupe]

1. you have a bad ground in the system...check again

2. i used sheild rcas to for that reasons..but ive ran into them also while using sheilded rcas...like the guy said above run them on oppsite sides of the car...

3. i need more info...what cuts on and off? they would dim if yoor amps draw too much power...cutting on and off? loose connection maybe...vibrating caused by the subs

[willcheung]

2. Make sure you run your RCAs and Positive cable at least 6" apart, better yet run them on seperate sides under the door sills.. Sometimes you may need noise filters.

1. I'm not totally sure, but once again keep your RCAs away from your power cables, and find some filters.. The noise is comming from the alternator..

thanks for the reply, I did room my rca from the driver side and 4 gage power wire on the passenger side. what is the noise filter looks like and how much and how many need?

so you don't think my alternator is bad, my car has about 120k with original alternator, should i change my alternator with a SE model 90amp one

[willcheung]

1. you have a bad ground in the system...check again

2. i used sheild rcas to for that reasons..but ive ran into them also while using sheilded rcas...like the guy said above run them on oppsite sides of the car...

3. i need more info...what cuts on and off? they would dim if yoor amps draw too much power...cutting on and off? loose connection maybe...vibrating caused by the subs

thanks for the reply,

1. what is cosider a good ground, i run a 4 gauge ground on the rear speaker deck. where should i run it?

2. I did run them oppsite sides

3. cuts on and off means, when i waiting at a stop light, the deck, head light, cigerette lighter outlet just die (shut off) and then turn back on and also my HID's circuit breaker kicks in.

[Ritz S14]

You would need 2 noise filters.. 1 Filter is for 2 channels.

I don't think your alternator is bad, just some produce more "radio noise"/whine than others..
http://www.hyperlighting.com/SNI-1.jpg
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=50552&item=5714025464&rd=1&ssPageName=WDVW

They work well, but it doesn't always eliminate the whine. They plug in the RCAs right before the amp, and the brown wire goes to ground.

Also, make sure your battery ground is at least 4 gauge(shortest possible). Better yet make it 1/0 if possible.

[kazuo]

I forget, someone remind me -- shouldn't the power wires be run ACROSS the engine bay to the DRIVER side of the car, while the signal wires from the deck should be run ACROSS the cabin to the PASSENGER side?

Basically, its supposed to keep the power wire away from the battery and the alternator, to keep it from picking up noise.

Anyway, here is what you do to make your problems disappear:

1) Get a Optima battery. (Yellowtop or Blue, which is for a boat, should do it :)
2) Get a high output alternator (a alternator shop or a specialty car audio shop)
3) Make sure the amps & deck are grounded properly (sand off the paint on the metal BEFORE you ground it, and put some grease or something over it so it doesnt rust; the grounds work better if theres no paint in between)

Once you do all that, you should be fine.

Good luck

[kandyflip445]

Upgrade your ground from the chassis-battery with some 4 guage wire or bigger. Make sure that the RCA's and the (+) wire for your amps are on opposite sides. Make sure that all the grounds are coming in contact with BARE metal.

The thing with the turbo sounding noise and the lines is ground looping. Check this page out for more info. Ground Loop is #126

http://www.bcae1.com/

[willcheung]

thanks guys, anymore comments?