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Unread 01-02-2014, 01:17 PM   #1
adamcarner
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1990 YJ Wrangler 
 
Join Date: Jan 2014
Location: Clinton, CT, Connecticut
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PCV Valve Problem

Hey all,

New to the forum!

I have a classy 1990 Wrangler 4cyl. My PCV valve keeps popping off whilst I drive the beast. The engine runs fine and purrs like a kitten. But it seems like there is too much pressure under there? does that even make sense? How can I prevent that bad boy from popping off, and seeping burnt oil smoke into my cabin, PLEASE HELP!



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Unread 01-02-2014, 02:13 PM   #2
Mark05059
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1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: quechee Vermont
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remove the valve cover, under the valve cover is a plate that is attached to the underside that gets plugged with crud. Its like a baffle. Also check the elbow for being plugged up.
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Unread 01-02-2014, 05:22 PM   #3
adamcarner
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Quote:
Originally Posted by Mark05059 View Post
remove the valve cover, under the valve cover is a plate that is attached to the underside that gets plugged with crud. Its like a baffle. Also check the elbow for being plugged up.
Forgive my ignorance, but "the elbow?" Still new to the jeep world, my friend!
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Unread 01-02-2014, 06:10 PM   #4
90DesertTanYJ
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There should be another port with an elbow in your valve cover that leads to your air cleaner assembly somewhere. This provides filtered air into the engine while the PCV has a vacuum pulled from your intake. Not entirely sure where on the 4 cyl. FI motors. I have a carbed 6 cylinder but the principles are the same. Look closely at your valve cover and there should be two hoses leading away, one is the PCV and one is the CCV. Make sure your PCV is operating by taking it out and shaking it. You should hear the ball inside moving around. The elbow has no ball or any other parts. Just make sure it is clear. The baffle below the PCV keeps oil from being sucked back into the intake but will accumulate crud enough to plug it off. Check tha as well. You might get another valve cover grommet for the PCV and that might help but you may have more serious issues causing pressure enough to pop the PCV out.
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Unread 01-02-2014, 06:25 PM   #5
jaycal3
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Quote:
Originally Posted by adamcarner View Post
Forgive my ignorance, but "the elbow?" Still new to the jeep world, my friend!
The elbow is just the bend in the valve... its bent like an elbow. Often times the valve gums up and does not function properly. When it does this, the "ball" inside cannot move and the pressure builds up thereby blowing the valve off the valve cover.

BTW, what makes your Jeep a "classy" one??
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Unread 01-02-2014, 07:13 PM   #6
adamcarner
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Oh, I replaced the PCV Valve, it's brandy new! Is this elbow the black plastic bend thats attached to the top of the PCV and goes into the hose? If so, thats brand new.

Quote:
Originally Posted by jaycal3 View Post
BTW, what makes your Jeep a "classy" one??
And that was a bit of sarcasm, hah! It's a cranky, crotchety old jeep
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Unread 01-02-2014, 07:31 PM   #7
adamcarner
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SO this is not my engine, but it looks identical, and it's out of a 90 wrangler 2.5L like mine.



So, I'm not versed in jeep engines, so just for clarity, The YELLOW circle is the PCV Valve, which I replaced and is brand new + put in a new valve cover grommet for it too. The BLUE circle is one that I never fiddled with.

The YELLOW is what is popping out under pressure. Is there something I can do to the BLUE one? That seemed okay!

I just wanted to be as clear as possible, as I'm not familiar with terms! bare with me!
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Unread 01-02-2014, 08:46 PM   #8
jaycal3
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Quote:
Originally Posted by adamcarner
SO this is not my engine, but it looks identical, and it's out of a 90 wrangler 2.5L like mine. So, I'm not versed in jeep engines, so just for clarity, The YELLOW circle is the PCV Valve, which I replaced and is brand new + put in a new valve cover grommet for it too. The BLUE circle is one that I never fiddled with. The YELLOW is what is popping out under pressure. Is there something I can do to the BLUE one? That seemed okay! I just wanted to be as clear as possible, as I'm not familiar with terms! bare with me!
I would check the lines that go to/from the PVC for any clogging. You may also have to remove the valve cover and clean out the baffles as mentioned earlier although I am not sure your engine is set up with the same baffles as mine, which has a ccv (it's a straight 6, 4L). You've got some crazy pressure building up under that valve cover.
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Unread 01-03-2014, 05:38 AM   #9
adamcarner
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Quote:
Originally Posted by jaycal3 View Post
You've got some crazy pressure building up under that valve cover.
I know, It's crazy. It was totally fine last week, this just started happening without warning. I'll see what i can dig up. In the mean time, is there anything else I can check?
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Unread 01-03-2014, 07:28 AM   #10
Mark05059
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you can do a compression check and see if your getting blowby and pressurizing your crankcase...
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1989 Wrangler Black Bone Stock 2.5l 5spd
/l , [____],
|---L--[]lllllll[]-
()_) ()_)==O=)_)
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Unread 01-03-2014, 09:43 AM   #11
tchoberg
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Reread this posted by 90DesertTanYJ, especially the underlined part.

Quote:
There should be another port with an elbow in your valve cover that leads to your air cleaner assembly somewhere. This provides filtered air into the engine while the PCV has a vacuum pulled from your intake. Not entirely sure where on the 4 cyl. FI motors. I have a carbed 6 cylinder but the principles are the same. Look closely at your valve cover and there should be two hoses leading away, one is the PCV and one is the CCV. Make sure your PCV is operating by taking it out and shaking it. You should hear the ball inside moving around. The elbow has no ball or any other parts. Just make sure it is clear. The baffle below the PCV keeps oil from being sucked back into the intake but will accumulate crud enough to plug it off. Check tha as well. You might get another valve cover grommet for the PCV and that might help but you may have more serious issues causing pressure enough to pop the PCV out.
I believe your problem lies with your 'blue circled' device which lets the 'filtered air in' which may be plugged allowing pressure to build and pop out the PVC valve.
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Unread 01-03-2014, 07:04 PM   #12
adamcarner
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Quote:
Originally Posted by tchoberg View Post
Reread this posted by 90DesertTanYJ, especially the underlined part.



I believe your problem lies with your 'blue circled' device which lets the 'filtered air in' which may be plugged allowing pressure to build and pop out the PVC valve.
Oh thanks man! I totally overlooked that post. Ill do a check on that once the snow clears a bit more here, (In New England) Perhaps tomorrow. Ill post what I find!

Thanks again for all the suggestions
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Unread 01-17-2014, 12:14 AM   #13
Landslide
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If all the grommets are correct and good, PCV valve is new and is still popping out you got some crazy blow-by, also check to see if oil is coming out of dipstick hole.
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Unread 01-17-2014, 07:49 AM   #14
Que89YJ
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1989 YJ Wrangler 
 
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Check the hoses the pvc and vent tube run to. The hoses get plugged and cause the pressure to build. Check both hoses to make sure they are clear all the way through.
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Unread 01-18-2014, 08:46 AM   #15
adamcarner
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1990 YJ Wrangler 
 
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Location: Clinton, CT, Connecticut
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Hello again!

So, I honestly think something was maybe half gelled or even slightly frozen that day (Twas Cold) But I just took it for a test run, let 'er warm up and it didn't pop off!! She's purring fine with no oil leaks!

I'll update if anything else happens!

Thanks again for suggestions. I'll check those hoses anyway to clear out any gunk that may be there
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