Persistent Engine Noise

Would an alpine work? I have been an XM customer for some time and would want a unit that is XM compatible.

I hate to hear that too. I just paid over $180 for this one, just now and it's not one I can just take back. Thank God my 860MP hasnt cause any problems... still though, and I'm not at all doubting your knowledge (please don't think that), but why would a radio that is working fine in one vehicle act up in another? The 860MP works great in my truck, no sound problems at all... and the truck has a full system in it (AudioControl ESP2, Kicker ZX460, 6.5 Resolution components up front, Memphis Studio 5x7's in back, Kicker DX700 on one Kicker 10L&). what would cause that? I can understand this particular Pioneer having a malfunction and causing problems but I'd think that if you took one that you knew for certain was not at fault and connected it to the system, then you would have essentially eliminated the HU from the equation. Why is that not the case? is it something about the electrical system in the car that is interfering with the signal outputs/circuitry of pioneer's HU's?

Well, I guess I'll have to face the turmoil of getting another HU. I was thinking of a Kenwood Excelon KDC-X591. It has all the features I want anyway and sorta wished I found it prior to the Pioneer. Anyone want to buy a near-mint Pioneer?? lol

I'm trying to be optimistic and light about the issue... it's sorta a downer though. I dont feel the car has a mysterious problem; however, if I get another HU and it still does it, that's going to be a nightmare, just like the Vette mentioned above or the Mark III i worked on years ago. I thought as one last test with the exising HU would be to take to the battery in the trunk and connect it directly there and rca's from there to the amp to see what happens. I'd think that if the radio truly was at fault, it would cause noise that way too. if it didnt, then something is amiss with the stuff in the dash or en route to the amp. The amp still could be an issue i guess... at this point, its confusing.

Yea ... misery loves company right?  I mean I've sunk $1000 into phantom problems like that too man.  It really sucks.

I mean... do you have a discman lying around?  You can get a headphone jack-> stereo rca plug from Radio shack for like $6 or so and try running your amps like that.  I've tested HU problems like that before. 

Vehicles do play a large part in the ground plane with the Pioneer units. I too have had my run ins with the vehicle and Pioneer combinations that have caused me grief. I'm not saying that the HU is more to blame than the vehicle but with the combination of the two, you will get problems. As far as another HU, if you have a buddy with an Alpine, Sony or whatever, just use that for now and see if you have the problem or not. You don't have to buy one, just ask to borrow one to find out if the problem is in the HU

I called a friend who has a copper chassis Denon unit he would let me test this with. Also, in regard to the comment with the Diskman from Sedate: I thought about something like that earlier in the day... I have an Archos GMini mp3 player that I can use as a source unit. I keep forgetting that I can use it for that.... so I will connect it tonight and see what is going on. I would think that if the RCA's, amp, wiring, the car, etc. was an issue, it would do it no matter what source unit I had, be it a radio/cd, an Ipod, or an mp3 drive such as the Archos.

I will post more later.

Did you do what was suggested with the test light yet? This little thing may solve all your issues.

I dont have a test like that anymore. However, I did try grounding out the shield of the RCAs. When I did, the noise became much worse. I also tried my mp3 player as a source, the noise was barely audible. Interestingly, after I did that with the mp3 player as a source, I couldnt get the noise to come back, unless it was by grounding the RCA shield. It was there before, there this morning but right now, it's gone, or at least to a point that you have to listen pretty hard to hear it. I revved the engine to about 3000 or 4000 rpms and still nothing. I did notice my switched 12v connection to the factory wiring was a little loose, to the point that the  unit was shutting off while I was trying to move it around. Aside from that, I didnt see anything unusual.