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Discussion Starter · #1 ·
I did a search on vacuum leaks to try to figure out what is going on with my car. Anyway, I read a lot about the PCV system. I removed my PCV (round 3" diameter valve above the N75 valve) and it had a lot of oily water in it. I guess my question is, what does a properly functioning PCV do? I noticed a spring in there but it really doesn't do anything. I expected to see a diaphram like the DV has, but there was nothing. Am I missing something? I am hoping this is the source of my boost problems.
 

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you PCV valve doesnt do anything about your boost. it stands for something like positive combustion valve :p :crazy:

or something like that, anyway basically it lets your engine(cams area) release any extra pressure it might have( sorry not good with names!!)...in other words the smaller hose that connects to the pcv valve, comes from the head part of your mottor and any extra fumes are released into the turbo so theuretically the fumes and posibble oil will just be burned off.

if you havent changed your DV, when you do, you will see oil there, dont worry, its normal.

what i did was sprayed the F$#K out of it inside the valve with brake cleaner, to try and clean all the oil deposits as posible, and re installed it.

i have no idea what the spring in ther is for, since the function of the valve is to catch all the oil. if you look into the hole, the is a litthe hole inside. thats where the air is supposed to flow in while the rest of the lalve serves as a oil resevoir.

at least thats my theory. but if it makes you feel better you can buy another one for $27 at thhe dealer.

it doesnt do much like i said, and it defenetively wont effect your boost!!

anyway, hope this helps.....

ALfredo

PS:ANYONE READING THIS: please correct me if im wrong :eek:
 

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The real pcv valve is not the one on the airbox, that is the secondary one.
The most important one is in a T fitting under the intake manifold, it looks and acts like a traditional PCV valve, in a turbo car this little part can reap havoc.... Leaking valve cover gaskets, excess blowby from exceeded pressures, built up acidic gases and oil dilution... etc...

It connects directly by a vacuum hose to the intake manifold to open and close, that line definitley does pressurize from the turbo.

If it did leak, it would bleed pressure into the crankcase under boost and boost in the crankcase aint' too cool' :)

So yes I believe it could cause a boost leak and more...I may be wrong but from the way it connects and logic... it seems this is true..

I cleaned mine, I also could get it to leak by mouth which is 2 psi max
But maybe when it sees 10 to 18 psi , it "seats" firmer... I would just make sure it is clean and freely moving, the main thing you want is for it to open during vacuum to get the vapors/pressure out.


TJ
 

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Discussion Starter · #5 ·
I also noticed a weird thing happening since my boost problems reared their ugly head. Before my problem occured, at idle my vacuum would read 22 in/Hg. While in neutral, I was able to push the throttle and hold it anywhere betwen 22 and 0 in/Hg depending on the RPMs. Now with the boost problem I am having, I hold the trottle (approx. 2000 rpm) and the vacuum goes to 10 in/HG and immediately falls back to 22 in/Hg. What is causing the engine to run in a vacuum even with throttle depressed? Or am I just crazy :crazy:
 

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TJ, your right about the pcv valve(its location at its possible breakdown). But the fact that WEEn2004 found iol in the secondary pcv valve, is proof that the other(primary valve) is not leaking, plus he would see evidence(oil) arounf the area slose to the oil filter. ALTHOUGH it would be wise to check it.

as far as it feeding the boost, im positibve that the pcv doesnot effects directly the boost. the only way it would matter would be if the pcv system would get clogged up and the mottor could not breath. then allot of other internal parts would be at danget(specially with that much boost)

and to answer your question wen2oo4: the boost gauge is supposed to run on a vacum(around 17-20 in/hg)when parked, even oftentimes under normal driving conditions(anyone w/ a boost gauge can acount for that). the gauge only rises over 0 psi when the boost is working under a load(thats the Boost).

you say that it drops when you hold it at 2k rpm....sounds like a leask to me, at if the gauge drops that fast, it just might be the tubbing to the gauge,....

alltogether, im starting to think its the boos gauge or the connections that might have a flaw.

this is a tough one(just by reading the symptoms), but i hope this helps a but.....

im not a pro, im actually fairly new to the Turboo world, i previously own(still own) an acura integra, it has 235k miles on it and still drives like a champ! its droped,w/camsfull exhaust...(its fast!), i still redline it when i get inspired it, and i've been the only one to lay a wrench on it, (just so you understand where im coming from) i speak from what i've researched in the B5 and work that i have allready done to my b5.


anyways...laters :b5:

ALfredo
 

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Discussion Starter · #7 ·
I thought it was the gauge too. But this past weekend I redid the nylon tubing to the gauge just to be sure there were no kinks. Same result. Even with the stock chip I was previously spiking at around 9 or 10 psi and holding steady at 7 psi. Now I can't get boost to go over 5 psi.. Chipped boost was previously spiking at around 19 or 20 and holding steady at 15. Now chipped boost only goes to 10 psi. And I know for sure it is not the gauge since prior to my boost problems the car had serious pull. Now nothing. Even with the chip installed producing 10 psi of boost, it won't pull like it did when I was totally stock and without problems.

It is driving me crazy. I am starting to wonder if there is a solder problem. I read a thread about that happening to someone recently. We'll see, car goes to the dealer on Thursday to get VAGed.

Thank you for all of your information guys.
 
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