Audio Systems: I cant seem to wire my car stereo right!, pioneer car stereo, auto part stores

Question
I have a 1985 Chevy Celebrity and a Pioneer car stereo.  My problem I have a yellow and a black wire and a grey wire from the car, and a yellow and black wires from the stereo.  There are two others that I cant place to anything.  There is a thin red wire labeled ACC, and a blue on labeled System Remote Control.  There doesn't seem to be a grounding wire.  I have placed yellow to yellow and black to black and it just doesn't work.  Please Help!

Answer
Hi Brennan!
What i always recommend to people who don't have too much experience (if any), when installing an aftermarket radio is to buy the wire harness adaptor adequate for your car, it is a  male connector that plugs into your existing wiring and it haves the universal color codes so you only need to connect color to color with your new radio plug.
But for what you wrote here i guess that you already cut the original plug, you will need then, to identify the +12v constant and +12v accesory or ignition, to do so you will need a voltage tester (the cheap ones sold on auto part stores)put the clip to groung and with the key in off position (or without the key better yet)check for the wire that have voltage, that should be conncted to the yellow on the radio, now turn the ignition on and look for another wire with voltage that should be accesory and must go with the red one in the radio, regarding the ground the radio have a black one but in some cars there is no ground wire on the harness so you need to loose a screw in the console (Check that it is on metal!)and put the stripped wire under it and re-tighten, the blue one (system remote) is for a external amp so you don't need it now.
Hope is clear enough, Good luck!