Topic: 2.5 liter spewing oil into my air box

[fireman411]

Ok I have read an older post but stil lost. I have a 90 and the CCV (on the valve cover at the back) has a line going into the air box. It is pushing air out insted of sucking in air like everyone states. What in the hell am I missing? 

[sharpxmen]

Ok I have read an older post but stil lost. I have a 90 and the CCV (on the valve cover at the back) has a line going into the air box. It is pushing air out insted of sucking in air like everyone states. What in the hell am I missing? 

check the other line going from the valve cover to the intake manifold, should not be blocked (sometimes gets clogged with gunk) - that's how the air circulates at idle and low throttle opening, from the airbox, thru the 90 deg plastic at the back on the valve cover, then out thru the brass fitting in the front and to the intake manifold (below the throttle body)

[Bounty Hunter]

Pull the brass fitting from the valve cover and clean it thoroughly.

[aj6502]

Pull the brass fitting from the valve cover and clean it thoroughly.

The brass fitting in the valve cover has a very small orifice in it to maintain a slight vaccuum on the crankcase. If the orifice is plugged or there is too much "blow by" on the piston rings oil will build up in the air box.

[fireman411]

by chance does anyone have a picture or diagram of this? I only found one brass fitting but it doesn't go to either the ccv or the air box

[chardrc]

a 1990 yj? you sure its ccv and not pcv? to my knowledge the tbi xj's have ccv and the  tbi yj's had pcv system. here is a pick of my 1990 with the pcv system. has a big black plastic cylinder at the back that contains a series of filters. and the front has the pcv valve that is supposed to suck the excess pressure into the intake.

make sure the pcv side has vacuum if not...
on my jeep there is too much blow by and it overpowered the pcv system and has ended up pushing oil out of the intake cover (has only pushed a little into the box but that's probable because those filters in the black plastic thing had a ton of buildup on them... )

here is a diagram of the tbi pcv and ccv systems.

[fireman411]

a 1990 yj? you sure its ccv and not pcv? to my knowledge the tbi xj's have ccv and the  tbi yj's had pcv system. here is a pick of my 1990 with the pcv system. has a big black plastic cylinder at the back that contains a series of filters. and the front has the pcv valve that is supposed to suck the excess pressure into the intake.

make sure the pcv side has vacuum if not...
on my jeep there is too much blow by and it overpowered the pcv system and has ended up pushing oil out of the intake cover (has only pushed a little into the box but that's probable because those filters in the black plastic thing had a ton of buildup on them... )

here is a diagram of the tbi pcv and ccv systems.

Ok the one in the back, the black canister, is the one that is blowing oil in the air box instead of sucking air like everyone is saying. So do I need to replace this? An d the pcv on the front what is that one suppose to be doing?  Its probably simple but I'm lost 

[dwtaylorpdx]

On the YJ the PCV valve (In this picture its the front valve cover connection) Is basically a check valve. It allows the engine to suck air from the valve cover into the throttle body to burn the vapors in the engine. The PCV valves usually last 60 to 100K mikes then they need replaced. I have cleaned them in a pinch but once they get gunked up they are usually toast. If you remove the valve and shake it it should rattle as the bead goes up and down inside. You should only be able to blow through it one direction.  When the valve gets plugged, the crankcase builds pressure and the vapor goes up the hose to the air cleaner box because there is a slight vacuum there and the crankcase has to send the blow-by somewhere...

PCV valve are quite cheap at your local discount autoparts store... Not an item I'd go to the dealer to get...

If you have not done a leak-down test on the engine, you might consider it. It will show you bad valves and or rings.

Dave