RudeXJ

Hey guys

So I recently swapped out my old cracked and leaking vacuum elbows from the valve cover and replaced the lines and replaced the rachet looking vacuum lines with new heater hose that fits OVER the elbows. It now idles much higher, I'm guessing that those rachet looking lines were a specific size that allowed a certain amount of air to pass through the system and the larger lines are what's causing the high idle???
Does anyone know the correct spec vacuum lines?

Basslicks

What year is your Jeep? I'm not sure what you're meaning by "ratchet lines"

This is what I used on my '92 when I replaced mine.

https://shop.advanceautoparts.com/p/...GiKBoCnf3w_wcB

RudeXJ

Sorry, that was a really rubbish explanation.

I have a 2000 with a HO head swap (0630).
So basically I had to replace both plastic elbows on the top of the valve cover.
I also replaced the the old worn lines with regular heater hose that was larger in diameter, not thinking anything of it.
It caused a higher idle, so I swapped the old lines back.

My question; is the valve cover vacuum an open system? There seems to be a one way valve on the line connected to the air box that the previous owner must have put in. (see picture)
Also is there a specific spec diameter for the lines as when I put hoses on with a larger diameter the idle increased and when I squeezed the line from the airbox the idle decreased.

Hope that makes better sense.

Basslicks

OOOOHHHHHH!!!!!! Okay, yeah that's not a vacuum line, that's a CCV tube. Just pulls filtered air into the valve cover . The CCV elbow on the back of the cover is hooked to the intake manifold. What it does is circulate combustible gases so they can be recirculated and burned. You should be able to pull that hose off all the way with maybe a slight change in idle, if any. It works off the vacuum of the manifold, yes, but it's a very low pressure vacuum.