speedometer problems

ok so my hell week is over, first my engine blew up, so i purchased one from a local salvage and spend the day putting it in... well guess what that one was blown up too, no compression... so i spent another day taking that one out, and then i purchased a good one for less money which was sweet but after putting in 2 engines, my speedometer stoped working... what should i check for first? and also what is the little plug the connects to the back of the d16y7 engine, above the oil filter and below the intake manifold, it has a rubber boot for it also, and a spring. thanks so much.

and also what is the little plug the connects to the back of the d16y7 engine, above the oil filter and below the intake manifold, it has a rubber boot for it also, and a spring. thanks so much.
Thats the PCV valve, it should be hooked up for the engine to run it's best.

Thats the PCV valve, it should be hooked up for the engine to run it's best.

yeah, i got that hooked back up, engine runs great so far.. still no speedometer though. anyone know anything?