What is the use of this outlined in the red box? When I took my motor out it was just hanging with the hoses connected but not bolted on? Shoould it be on or off? I have a b16 head on a jdm gsr bottom if that info is needed.

 

its the factory "catch can"
i do believe its just a pressure fit into the back of the block

 

Just leave it, not bothering anyone.

 

dont know what it its called or what it does but i see the PCV valve on top of it so it must be needed and i'd leave it alone

 

What does it smell like?

 

Its the PCV breather box and you either need it or need to replace it with an aftermarket catch can/breather system.

 

Any recommendations on replacements? And just small info the pic isnt mine just the only one I found that was clear enough to post.

When I pulled my motor out I found it dangling just hanging by the hoses I had to find a bolt and washers to sit it back on the motor.

Only reason why I am asking what does it do etc is cause after I put my motor back in I'm having idle issues and wondering if replacing this part can help etc

 

Well I don't know how you have it hooked up but if it were loose it would prolly leak oil and maybe cause idle issues. You either have it venting to atmosphere and the intake plugged or you have the PCV valve connected to the intake or maybe you have it connected to the intake with no PCV valve. If it didnt have the PCV valve and was connected to the intake it would idle really high and be blowing alot of smoke out the tailpipe.

 

It is the PCV box Positive Crankcase Ventilation, it lets the crankcase pressure get relieved under a load. Ditch it and put a vent can on there, the stock PCV is way undersized on the B series and is known to cause oil burning.