Water may not be hot enough. If d/w is far from hot water tank, water may not be heated warm enough by the time d/w fill valve shuts off. Many good dishwashers have a heated water option. If yours does , try it. Finally: Cheap d/w without multi level cleaning don't work well. Also, there is often a rinse only cycle which gets rid of heavy food deposits, so they aren't dried hard on the dishes when you are ready to do a load.