Crankcase Fresh Air Inlet CCV

EvilRbt

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Los Angeles
I have 92 YJ.

Last week I cleaned out the throttle body because it seemed like my gas pedal was sticking.

Since then I noticed high rpm’s in neutral and when shifting. Today I found the fresh Air inlet was disconnected from the crankcase and oil had blown out.

Now, when moving the aftermarket air filter someone put on, *maybe* I disconnected the fresh air intake?? I don’t see how it could have blown out bc of its insert-and-twist design.

To my question… when I reattached it doesn’t feel airtight at all. Shouldn’t it be? Was there a rubber grommet that must have come off? I’m assuming the lack of a seal could be causing the high rpm’s.

If there IS a grommet and anyone have a part # I’ll love you forever.

Thanks!!!
 
If im following you correctly the lack of gasket on the rear air tube from the VC to the air cleaner will not make a high idle or a vacuum leak. Yes, there was a 1/8 or so thick round rubber gasket there, or should be. Its the other end where the small line coming off the TB or intake manifold to V/C could cause a vacuum leak if unhooked or one of the 30 year old rubber 90'ies cracked. I'm guessing when you cleaned the TB some of the crap you knocked loose is now stuck in the port or on the pintle of the IAC thus the high idle.
BTW, the brass orifice screwed into the front of the VC is basically a PCV breather. It will in time carbon up and could use the occasional clearing. I clear my 91's out fairly often while doing the service. That hole is very small so DO NOT drill it out,just use a small wire or something like that to clear it.
 
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If im following you correctly the lack of gasket on the rear air tube from the VC to the air cleaner will not make a high idle or a vacuum leak. Yes, there was a 1/8 or so thick round rubber gasket there, or should be. Its the other end where the small line coming off the TB or intake manifold to V/C could cause a vacuum leak if unhooked or one of the 30 year old rubber 90'ies cracked. I'm guessing when you cleaned the TB some of the crap you knocked loose is now stuck in the port or on the pintle of the IAC thus the high idle.
BTW, the brass orifice screwed into the front of the VC is basically a PCV breather. It will in time carbon up and could use the occasional clearing. I clear my 91's out fairly often while doing the service. That hole is very small so DO NOT drill it out,just use a small wire or something like that to clear it.

I’ll check the port. Thanks!

So is it normal for the air inlet elbow to be somewhat loose where it connects to VC? I can’t help but feel it should be a firmer fit, even if not airtight.

You aren’t kidding about 30 year old lines. Let’s just say brittle is a theme.
 
I bought a new 90 with the gasket from Quadratec IIRC. Its definitely better but not what id call water tight.
https://www.quadratec.com/p/crown-automotive/rear-pcv-valve-elbow-yj-xj-mj-zj-53030492

If the other connection to the VC, you described as brass orifice is indeed clogged, do you think the pressure could have blown out the elbow connection of the air inlet? I find it hard to believe I left that disconnected.

I’ll check the the pintle of the IAC and clean it. Or maybe just order a new one. I’m sure mine is pretty old.
 
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It doesn't take long and it might be worth removing the valve cover to get to that brass fitting. It's no wonder any air got through mine on a 2.4L The fitting is under one of the towers inside the cover.

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