Is the spray arm blocked?
A blocked spray arm can delay the detergent and soil removal. If the delay is too long, too much residue can remain in the wash cycle and the final rinse might not provide optimal performance.
How to check? Before starting the cycle, spin the middle spray arm by hand to confirm there are no items preventing it from freely spinning. If there is resistance rearrange the dishes.
Were the dishes loaded correctly?
If water cannot easily reach all surfaces of the dish load, soils and detergent can be retained longer and impact dilution. Maintain good orientation and spacing of items to minimize shadowing and pooling of water.
Was the correct amount of detergent used?
If using powder or liquid detergents, don't overdose. Consider using a premium detergent packets that typically have chemistry to minimize damage to dishes.
Is the detergent old (if using powder detergent)?
Older detergent exposed to air can clump and not dissolve well. Use fresh detergent only. Clean out the dispenser. Do not allow the detergent to sit for several hours in a wet dispenser. Clean the dispenser when caked detergent is present.
Was the correct cycle used, is the water pressure too low, or is the water temperature too low?
If your food soil is heavy on the dishes a heavier cycle may be required to fully clean your dishes. Check to see if the water pressure is high enough for proper dishwasher filling. Water pressure should be 20 to 120 psi (138 to 828 kPa).
CLICK HERE for more information on water temperature