Ground Loop has beaten me...help

[mystikarkitect 10+ year member]

Hey all, just wondering if anyone can help me. I've pretty much run out of options and ideas. Some of you know I installed a Pioneer Avic Z-1 HU a few weeks back in an 07 Avalanche. At first, with no amp in the system, everything worked great. Soon after I installed a JBL BP1200.1 amp in the truck and grounded it to the brackets that hold up the back seats in the Avalanche. I assumed the brackets hit the vehicle body so I grounded it there. The amp turned on fine but one of the subs was faulty (TC-1000 8") so I took out the subs and the amp. During the removal, the ground wire and the power wire touched and sparked. I turned off the positive terminal and removed all wiring. Well this is when the ground loop started.

Im not sure if it was the positive and negative touching or what but the next time I got in the truck there was engine whine. So the next day I ripped out all wires save for the RCAs and remote wire to see if that would fix the problem. It didnt. So I drove around for a while with this annoying engine whine in my relatively new truck. Something I was not enjoying. The HU still worked fine. So I came on here and saw possible fixes. There was no amp in the system anymore, so it wasnt the power wire interfering with the RCAs. So I got new RCAs. I bought some Stinger Bullett Series RCAs and took the old cheap RCAs out and put the new ones in. Still had the whine. I removed RCAs completely to see if that would remedy it, and it didnt. Then recently I tried the different fixes I saw on here. Tried grounding it at the battery, tried grounding it where the amp was ground. Neither worked. So I saw the last fix which involved wrapping bare wire around the RCAs and grounding that into the HU itself. Tried that and *that* did not work. At this point I was tired and just shoved everything back into place. I don't really know what else to do. At this point Im at the point where Im just going to rip everyhting out of the truck and leave it stock to get rid of the whine. Im out of ideas. Thanks to anyone who helps. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

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[Pl8er 5,000+ posts]

Try moving the speaker wire as far from the power and ground as you can. Check for the loop. If still there try moving the RCA's as far as you can too. You may want to pick up a ground loop isolator, they are cheap and can be gotten online or at radio shack.

 

[danp129 10+ year member]

I would try the factory HU if you still have it and it's easy to install. You may have grounded the remote and zapped something.

 

[synikalt 10+ year member]

wait..so your saying its NOT a good idea to run the speaker wire near the power wire? i was aware of Rcas...since they pick up signal but speaker wire?

 

[helotaxi 5,000+ posts]

Neither signal nor speaker wire will pick up noise unless you have a serious problem with your battery or alternator.

A ground loop isolator is a band-aid. It might get rid of the noise but it will usually kill your frequency response as well. Hardly a real solution when there are real solutions out there.

First isolate the noise. Unplug the RCAs from the amp. If you still have noise, the problem is with the amp. That's a distinct possibility since you shorted the leads (always disconnect the neg wire from the battery before working on wiring). If the noise is gone with the no signal going to the amp, then the problem is with the HU. Usually the HU ground is the problem, but Pioneer units have a history of the internal signal ground path resistors blowing allowing a ton of noise into the system. The solutions to this are: send the unit to get repaired or ground the barrels of the RCAs at the HU. There are several threads about how to do that on the forum here.

 

[mystikarkitect 10+ year member]

When I unplug the HU RCAs the sound goes away. Because its a Z-1, it has specific front, rear and subwoofer RCAs. When I disconnect the front and rear, the sound goes away. Im going to try one last thing and that is actually leave the amp plugged in and on and ground the HU where the active amp is grounded. Its the only thing I haven't tried. If that doesnt work then I'm going to go with a ground loop isolator. It's the only option I have left.

 

[NeverEnuffBass 10+ year member]

Check to be sure the RCA's are not ran over any factory wires. That could also induce system noise.

 

[mystikarkitect 10+ year member]

Well fellas...sometimes things just aren't meant to be. I tried the common ground with amp turned on try and it did not work so I went to Radio Shack and got ground loop isolators (2) one for the fronts and one for the rears. Since the isolator can only control one set of RCAs at a time I needed two. So I got 2. Well I put em in and they really helped the noise out, isnt drowned out completely but it can only be heard very very faintly if the truck is running, standing still and the A/C is off. This is where it gets funny. Finally after it was all said and done, I put my H/U back in....and its freezing at the startup screen. If any of you are familiar with Avic Z-1s, there is a Pioneer startup screen at the beginning. Well it stays frozen there now that there is no whine...lol. Next Nav unit I buy won't be a Pioneer...I'll go Eclipse or maybe even Alpine. I was a solid Pioneer customer before this happened, and from Avic forums it seems to be happening quite a bit to a lot of people in hot climates. Go figure. Well thanks for all of your help guys, I really appreciate it. Sucks but oh well.