Thanks a lot for your answers.
I was a bit too rapid in my case changing.
Now it works fine. The metod witt the builtin funktions does not work at all. I have tried that earlier. Strange!!
I have a very strange behavior on my ADC on a 18F452:
I use all channels and ref on 3.
I use 10 bits.
My problem is that if channel one get over 256 it spills over to channel two.
The code looks ...