i have a factory '84 EFI, so its the older 22r, but its got the injeciton on it. and last weekend i went and bought a second manifold to polish up, and maybe even paint a part of it, but without having the truck out of comission while it was being done. figuring that all of the EFI manifolds were the same i didnt really inspect either of them. as it turns out, the one thats on my truck, has 2 hoses that the other manifold does not. one of them goes strait to the top of the valve cover, and the second goes under the manifold to the throttle body, underneath the screw on the very front of it. my question is what's their purpose? and can i get away without them??
then can you get away with just putting like a small filter on it and not having the hose to the manifold?
I'm not 100% what the line going under the manifold is, but the second is the pcv valve as others have stated. Yes, you can put an air filter over it, but be careful. The pcv is an emission control device and you may be screwing with smog issues, depending on where your from.
Simple! It takes unburned gases (blowby) that can sometimes escape the combustion chamber and routes it back into the manifold. The rerouted gases will essentially be mixed the the air/fuel mixture and be reburned. This is why I yank all my emissions crap off and I use a filter on my PCV to vent all that unburnt crap to atmosphere. I definitely don't want any other crap in my mixture, other than some clean, fresh cool air and some gasoline...or maybe some NOS...ooo ooo, and maybe some water/methanol. So there you have it...in a nutshell
Does the new one have an angled down throttle body mount too? If it doesn't its the newer style. There were 2 EFI manifolds and from what I've heard, the newer style is better. Just can't remember why exactly.
