Noise problems, WITH THE CAR OFF!?

**sdashiki** · 01-13-2007, 03:20 PM

Ok, scenario:

bought my woman a radio for xmass. got around to installing it with a Best Buy bought wire harness. wouldnt turn on. dont know why, but it wouldnt. so i figured, maybe its the radio.

went to my car as a test bench, disconnect my radio from the black, red and yellow wires...

reconnect black, red, yellow to the gf radio, it turns on. so its gotta be the wire harness.

brought back harness to best buy, no problem.

get back to hooking MY radio back up and now there is a **** TON of noise coming out. and I havent even turned the car on yet, just the ACC position.

so, the car isnt running and im getting hella static.

why?

i jiggle the wires all over the place, nothing does a damn thing.

pull on the factory harness, nothing.

turn, twist and jiggle all 3 power wires, nothing.

removed all 3 pairs of RCA one at a time, no change.

remember, the car is off, so this aint alt whine, so its all new to me.

what could have happened in the 3 minutes that my radio was disconnected, my gf's connected and removed, and my radio connected again?

IMO, nothing could have happened. but something always does.

my quick idea to test something is to take the radios ground wire and run an extension to the bolt i have in the back as the amp's ground point. that way the amp and radio are 100% definitely sharing the same ground source.

whats happening here, and is my experiment a good idea?

**Grimoire** · 01-13-2007, 03:57 PM

What kind of noise is it? Popping? Static? explain the noise, because Ive had ever single kind of noise come out of my amp and computer AND HU and Ive fixed damn near all of them. Do you have an amp or is it HU to speakers? Everything Stock?

**2k1Toaster** · 01-13-2007, 04:04 PM

My bet would be on the speaker wires connection if you are using the amps internal amp. Either from the HU connectors to the wire, or from wiring harness to speaker connects. COuld just be that one of those little rubber things that slide over the connector to protect it came up a little bit and now they are touching causing static.

Of course if you are using an amp to the speakers, then nevermind!

**Grimoire** · 01-13-2007, 04:05 PM

Thats what I was thinking. Same concept as putting a battery to a speaker wire to find out which speaker its going to, youll hear static when you do that. So, it may be that your getting power on your speaker wires. The sound will say. popping is the HU (in alot of cases) and static is power, (in alot of other cases.)

**sdashiki** · 01-13-2007, 04:39 PM

Setup:

Headunit >> 3 rca pairs out >> 5 channel amp >> f/r crossovers >> stock wire harness >> components

the front/rear component woofers run from the crossovers back to the stock wire harness as I wasnt going to run thru the door when the stock harness has 4 pairs of connections already for me to splice in. the tweets go right from the crossovers as they werent part of the stock config, i dremeled mine into my a pillars.

its pure noise static, like a radio station not coming in clearly. playing a CD you can hear the CD, but its like a crappy radio station.

the headunit only outputs a sound signal to the RCAs, and also has input from the IP-BUS from my iPod on occasion. I disconnected the BUS, no change.

i dont even have the radio antenna hooked up, as I dont listen to the radio, ever.

so the stock harness has +/- and ACC connected to the radio, and it accepts the input of the crossovers to the door woofers.

any help is still appreciated!

and like i said in the OP, i only disconnected the power connections briefly and reconnected them, granted i moved ALL the wires to do this, so maybe something happend, but on a cursory look at the wiring, i saw nothing disconnected or moved. so this is ALL new to me.

**Abmolech** · 01-13-2007, 06:50 PM

It is possible you have blown the ground traces on the headunit.

As usual you need to start somewhere. Make mute plugs for the power amplifiers and test.

Other choice is to try using a battery powered head source, such as portable stereo etc. Disconnect the RCA from the power amplifiers and use the battery head source.

No noise?
Then it is RCA or headunit etc related.

Noise?
Gain on power amplifiers set too high,
Passive crossovers picking up RF noise.
Grounded speaker wire
Faulty amplifier.

**sdashiki** · 01-14-2007, 09:01 AM

alright.

has to be the HU.

removed all speaker wires one at a time from the amp, no change.

removed all the RCAs one at a time, no change.

remove ALL RCAs at once, change....

hooked up my iPod with RCAs into the 3 channels, sounds great!

Has to be the HU.

still flabbergasts me though. i disconnected the HU from the factory harness ground, ran a long wire to the back where my amp is grounded, held there with my finger, got the HU to turn on, but no REAL change in the static.

typically, when this happens (engine whine) jiggling the ground and all the wires behind the HU produces some sort of change, less, more or cracklin static. this does nothing as far as i can tell.

wtf is goin on here? how can i test this any further?

should u remove the HU, bring it somewhere and have them bench test it with some speakers?

or should I try another HU in my car and see if it too gets static?

in either case i guess id learn if it was the car's connections, or the HU itself.

neither answer pleases me as I didnt really change anything!

i hate not having a HU...

**Abmolech** · 01-14-2007, 02:21 PM

Next step is to eliminate RCA interference and/or ground supply problem.

Try to leave the RCA leads in there orginal position.

Remove the head deck hook up the iPod with RCAs into the 3 channels and try again. (Make sure the ignition is in the accessory position to simulate the same conditions as the head deck)

Noise?

RCA ground missing, pull em apart and resolder (use a DIMM to find and recheck)
No RCA lead problem?, then it will be induced from power wires nearby.
Almost guaranteed to be near the head unit. Usually the largest diametre.

Try to move them away from the RCA leads and tie them up.
Rinse and repeat.

No noise?

Most likely blown earth traces.

Try earthing the OUTSIDE of the RCA lead (metal part) adjacent to the head unit. (all three)

No Noise?

Need to get it repaired. You should never have the power on when removing RCA leads, a short circuit to the centre pin (earthed), will overload the traces.

**sdashiki** · 01-15-2007, 09:25 AM

i dont have anymore electronics with RCA connections.

my iPod is male connectors.

if im to test my rcas, id need another female RCA output. like a drum machine or something.

there are no power wires near the RCAs...

again this morning i tried to test things out.

if you change sources on the HU, radio>cd, the static changes a bit...sometimes the static seems to have a rhythmic pulse to it too...? still, the car is OFF.

how do i test for the traces on the HU being blown...

i believe you say take a wire, touch to metal HU case, and touch to the outer ring of an RCA? all 6 RCAs, or just one? Or just a pair?

**sdashiki** · 01-20-2007, 04:20 PM

Alright, got some free time this morning.

And, I found a screw hole in the back of my HU. Must be for this explicit purpose:

I shoved a wire in there, and then put the other end onto the outer shielding of ANY of my 6 RCAs, BAM no noise!

So.

Now what?

I can get a screw to hold the wire to the HU, but what about the other end?

Ductape it to an rca?

Ductape an RCA to the back of the HU (the screwhole is in a big ol piece of metal chunk that is the back of the HU itself)?