Valve Wetting and Wall Wetting in Intake Manifold Walls, Runners Walls or Cylinder Walls

What is difference in Valve Wetting and Wall Wetting ?  Valve Timing is done for air or for fuel?


If valve timing is not done for fuel injection timing then "will fuel go on the back of valve stem?".
If liquid fuel sprayed on cylinder wall i.e combustion chamber wall, it works as coolant and reduce temperature as a result NOx. But if fuel is sprayed on Intake Manifold Wall, Runner Wall and Port Wall then it will harm in two ways :

1- wrong calculation of amount of fuel. ECU is sending from Injector X amount but Y is going in chamber for a particular single stroke.

 2 - Lower Fuel Efficiency, Un-burnt Hydrocarbon and bad emission.  

Proposed Solution 

To prevent injector rotation, there are two suggestion has been proposed

1-    Use Injector Locking Clip to prevent injector slide into manifold hole

2-    Use Long Reach Nozzle Injector to prevent runner wall wetting 

Valve wetting when timing or axis of injector spray is not correct. If Valve timing is wrong, fuel injector will open when intake valve is in closed condition or near closing so fuel will not go in chamber but on the back stem of valve. 

Wall wetting is phenomena of fuel particle going directly on wall of intake, runner, port or cylinder As explained above and shown in below picture.