Audio Systems: iPod / iPhone Strange Audio Output, true stereo sound, female rca

Question
I have a very strange phenomenon (at least to me), and I will be genuinely
impressed--and grateful--if you can help.  I have an iPhone that I am trying
to connect to a car stereo and a home stereo.  I have hacked the din for my
car stereo (original, 1989 Acura Legend head unit) and have been successfully
playing for the past few years a Sony CD changer hard wired via rca outs from
the changer to the head unit.  Sounds great (much better than FM kit).  When I
connect my iPhone to this din via an 1/8 inch plug to RCA adaptor, whether
from the headphone port (yes, it is modified to fit the recessed port) of from
the standard dock line out port, the sound seems as though very deep reverb
and echo have been added (like the music is coming from a cave), and some
tracks, usually the vocals, are faint and difficult to hear and others are louder
than usual.  Now the stranger part--if I leave one rca plug plugged in to one
female rca plug and then touch the center prong of the other male rca plug to
the outer shield of the other female rca plug, the mix sounds normal with the
exception that it appears to be in mono.  I have reversed the wiring on one of
the rca plugs by cutting the wire and connecting the ground to the "signal
carrying" wire (basically to accomplish what I did by touching the center
prong to the outer shield).  Now I can listen to the iPhone through the car
stereo, albeit in mono.  I also get this same result when I connect to the front
rca jacks on my VCR in order to connect the iPhone to the home stereo
without having to turn the receiver around and plug directly into the back.  
HOWEVER, when I do plug the rca jacks in to the back of the home stereo
receiver directly (rather than through the vcr), voila--true stereo sound
without the weird verb and echo effect.  Any ideas?  I'm stumped.

Answer
You might want to try using a professionally designed interface kit.  Take a look at

http://www.installer.com/ipod/

and see if the Acura kit will work for your car.

I think the problem is you are still connected to the changer and the output of the iPhone is therefore connected to the output of the changer and is getting an out-of-phase feedback signal causing sound corruption.  Try disconnecting from the changer and feeding into the head unit with the rca only.

For the vcr you are going into the outputs rather than the inputs maybe?  That will do it.

Let me know more if you don't get it figured out.

Cleggsan