71Nova said:

...snip...Today I re did the grounds to the head unit and xm unit. 16ga ground wire about 8 in long bolted to a sanded shinny part of the firewall...snip...

The firewall isn't the best place to run a ground...especially a ground that is as important as this one is. With the issues you are having, I would buy a junction box, hook it to the firewall and hook your grounds to it. Then run the other side of the junction box directly to the battery...or where the negative cable hooks to the frame or block. You can buy a battery cable that has an aux lead to it you could attach it to. Experiment where you fasten that lead. If it is a ground issue, I'll bet that takes care of it. You are hearing feedback...probably from the alternator. You need to isolate that.

I have now oficially tried everything. Since my last post I have replaced my 100 amp alternator with a new powermaster 140 amp alternator that they said is for stereo competition. Even though I am not interested in stereo competition I figured that means it works great with stereos. I have also re ran the always on power to the battery and installed PAC ground loop isolators. Another thing I tried was I installed a American International S15A noise filter that goes on the always on power line. I found it on crutchfields site. none of these things made any difference so today I mailed my AVIC-z1 into pioneer repair center to have it checked. Hopefully it is those small fuses that whtcrxghst was telling us about. Hopefully I will get it back, plug it in and won't have any noise.

Oh I forgot to mention to 03Aviator My battery is directly grounded to my firewall.

I called pioneer tech line and asked for a status on my z1. They asked me for my tracking number from when I shiped it to them. After I gave her the tracking number she told me it had been repaired by replacing an internal fuse and re setting the system. I think it is cool that they track the repair from the ingoing tracking number. Just remember to save it if anyone needs repair. I should get it back in a couple of days. I just hope that fixed the prob and the fuse never blows again. I will keep my fingers crossed.

Hey 71Nova,
I wonder if it is your spark plug wires. Some of the performance ones are not suited for cars with radios and cause a but load of noise in systems.

Yea, I was wondering the same thing for a while, but I later heard that if that was the problem it would only have increased noise when the radio is selected. You know like AM and FM. I always have a but load of noise. You can even hear the hard drive searching over the speakers.

Just to let you guys know and to try to contribute to the info here I got my avicz1 back today! It was out of my posession for exactly 1 week. I live in So cal so the shipping was only one day from the so cal pioneer repair center. I pluged it in and it is working great!!! Finally after owning this unit for about 6 months I dont have any alternator noise!!!!!!! They said they replaced a single internal fuse and reset the system.