Ground Loop Problems

[mystikarkitect]

Hey all, just wondering if anyone can help me. I've pretty much run out of options and ideas. 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 started looking for 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. 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. Apparently Pioneer HU's sometimes have a bad internal ground. 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 everything out of the truck and leave it stock to get rid of the whine. Im out of ideas. Thanks to anyone who helps.

[bridge4d]

Just to be clear, did you say you took the amp out completely and still got the whine with just the HU powering the system? Or are you still running the amp?

 

If the latter, I'd say you you blew out some of the amps filtering circuitry and it's no longer able to get rid of the 60hz noise that's inherent. If the former, you might want to try a ground loop isolator on your power inputs for the HU. You can get one a radioshack or most any of the large national chains that sell car audio.

 

They also make noise filtering RCA cables with ground loop isolation (once again radioshack). They are a bit more expensive, but I'd probably try one of those first between the HU and the amp and see if that works.

[workingman70]

Im Having the same problem. awful motor noise with a pinging noise? accidently arked positive and negative.

[whtcrxghst]

Try grounding the RCAs. If that doesn't work, send your deck in for repair...You probably popped the fuses on the RCAs when you arched

[workingman70]

ive got 3 amps sysytem been intalled for 6 months ever since i arked the amp powering the subs ive had motor noise from hell from all three amps tested all rca cables no change, i even get a strange pinging noise. sounds like the hard drive in the hu is interfering. what to do?

[SHOOTER]

This is a very commen problem, It happend to many z1 we did big systems with at my old shop and now just did it to my z2. The rca ground loop isolation thinggy in the z1/z2 is grounded to the chass of the unit, something commonly goes bad and they say ground one of the rca's the the deck's chassy but thats just a bandaid never fixes it for long, it just fried my preouts.... stupid pioneertechs. anyway's no way of fixing it except sending it to pioneer and having them replace the ground loop insolation part, if you ground the rca your only going to have worse problems later on, but dont feel down you are not alone I have personally witnessed over a dozen units with this same problem

[bdeitemeyer]

I have the same problem, ended up using a ground loop isolator & that solved the problem...too bad it's just a band-aid fix.

[Eggsack]

This is what was emailed to me from Memphis techs and it worked for me:

 

What we were suggesting was:

Tap off from the 12v power lead (constant power) and the ground <<<<

and run those wires back to the head unit. Since the remote turn on lead is going in the opposite direction (coming

from the head unit to the amp), take it and twist it around the 12v and ground coming from the amp back to the head unit.

 

The purpose of this technique is two fold;

it allows your head unit and amp to theoretically MATCH the 12v constant and the ground.

And since you're twisting those wires back to the head unit around the remote turn on, it helps cancel noise as well.

 

So, just to clarify- your head unit will no longer be connected to 12v constand and ground in the radio harness:

it will get it's 12v constant and ground directly from the amp. And since the remote turn on is running the same path

as those wires will be running, it's a good idea to twist them (or braid them) around one another.

[ThaBlackMamba]

WOW, I'm having the same issue right now. I was installed a PAC Module and I didn't realize that the car's batter was still connected. The 12V wire touched the ground and there was a spark. I poped 2 fuses and thought that was the end of it. I powered the unit up and heard this awful whining noise. Just like others, I litterally re-wired the whole system and the noise is still there. I guess I'll have to send my unit in for repairs

[sneach]

What is the going rate for a factory repair of this problem?

[sneach]

For those who may be curious, I emailed Pioneer and they said repair costs on the Z1 was a flat $200 for out of warranty work.