I've got a custom auto sound stearo. I have my memory connect to b+ on the fuse box. Now when I crank the car to start it, it loses that connection and the memory gets reset. Its not a lose connection, becuase it remembers the CD somestimes, just not when i crank it over. Like If I'm listenting to it on 'start' then turn it it 'off' then back to 'on' it remembers fine. Just when i crank it again, it loses it.

You could either have it connected in the wrong spot (that I doubt as I have not seen cars with a 12V terminal that has power in all key positions except when cranking the starter) or you may have a problem with the voltage going below what the radio needs to retain memory. Most radio's will work between 8-15 volts and while you are cranking that line may drop down below, let's say 8 volts and long enough for the memory to clear.
I have seen car with bad voltage regulators to where the voltage spikes above 15 volts and the radio cuts out from too much voltage.
Jim

Agreed on the voltage regulator. Iam getting a new one becuase i was getting voltage spikes, and now its turing off when it happens. Do I need a regulator for a certain amp altenrator, or just a regulator?