My GE dishwasher has left over water in the bottom of the pan after each wash cycle. Not much but it is there. There is also some black gunky stuff floating in the water that is coming from the sump valve. I removed the dishwasher last year and removed the sump and cleaned it out. I was full of this black gunk which I assume is old food residue that DOESN'T get washed down the drain.
I am going to replace the sump with a new part but my question is...do I need any other parts and why does this stuff collect and not get washed away and down the drain?
Otherwise the DW operates normally. Is there a drain valve not openning all the way to allow the food particles to wash away?
I seem to have the same problem. The dishwasher is less then a year old. I started to notice this when during each wash it was producing a smelly odor.
Sump replacement 
