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Discussion Starter #1
Hey All, I own a turboed 99 hyundai excel 1.5L DOHC and currently I am having problems with the crankcase gases not getting removed properly out of the crankcase and making puffs of white smoke when changing gears. I know its because of this because my efforts on fixing it changes the amount that it happens but it still does!!!

When the car was turboed i had the PVC hose and the other valve in the crankcase's hose T in together where they would join to the oil catch can and then to a line to the turbo side of the intake. That worked perfectly till suddenly last week i got white smoke coming out of the car. I noticed the hose from the PCV to the T was kinked so i got new thicker hoses and reconnected them and the problem remains!

The PCV rattles like it should so i dont think its that. I then tryed and disconnected the 2nd valve from the system and making the PCV > Oil catch > Intake and have 2nd Valve > Air Breather Filter. The problem still stays!!! WTF is going on?

How often do PCV valves break? could it just be that cos blowing air into it makes it work as it should, blocking it one way but not the other... HELP!!!
 

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Im not sure what you mean by 2nd valve, but I have a 1.5 sohc. I have a breather filter on one side and the pcv side is hooked to the manifold like it originally was. Just stuck a breather filter on the side that originally went to the intake. Some will say its no good, but it hasnt caused me one problem. Im told it can lean you out at idle sucking in unmetered air but like I said I havent had a problem, its been like that since i was n/a.
 

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Discussion Starter #3
Hmm, okay. By 2nd valve i mean there are 2 nipples coming off the crankcase at the rear... So the SOHC has 2 valves right next to each other on the rear of the rocker cover Just like the DOHC?

I just dont get why mine has just started screwing up... I read somewhere that the way i had it (PCV and 2nd Valve T'ed together then joined to oil catch can would create problems as one blows stronger than the other so one valve might not work right...) was wrong so now all this is throwing me all off...

So do you think if the PCV is hooked to the intake manifold like previous and the 2nd valve is oil catched then that might work? i think its the only setup i havent tried but that way is alot of messing around cos my BOV is hooked where the PCV "was" and they are diff sized hoses...

I just thought that the PCV was the primary expeller of the gases hence oil catching "that" valve...
 

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I remember reading why hooking your intake side of the pcv (the one w/o the pcv valve) to the intake side of the turbo wouldnt work, just cant remember exactly why. I think its expelling under load and sucking off load if i remember right I posted a diagram awhile back somewhere.... Neways if your having trouble with it like that then yes change it over. You can just throw a breather on the intake side of it and use the catch can on the pcv side to prevent that crap going in the IM. The filter will eventually get dirty and u will eventually have to clean it but Im going to assume you pop ur hood to maintain it once in a while ;-) BTW if you have your bov hooked up to either of the sides for the pcv change it over immediately. That does not work properly and doesnt even begin to match IM pressure/vacuum. That could also be your problem.... I used the pcv valve intake on the IM to run my ssqv once and it would sound off but hardly, it wasnt even close to as loud as it was on the IM which made it obviously thats its a VERY poor choice for bov vacuum. Just use the fuel pressure vacuum line or some other source...
 

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Discussion Starter #5
My BOV vaccuum source is the Intake manifold where the PCV used to hook on... just like you have it (i think)... that runs just fine... But my attempt at running the PCV > Oilcatch > Intake while the 2nd valve > Breather filter didnt work... I mentioned that...

But what gets me is why this problem hasnt happened for like 3 months! and there were no changes to the system...

So my options are PCV > Oil catch > Intake manifold (with 2nd valve T'd in? or run hoses like stock)

Or just... Put every thing back to stock i guess and have no catch can...

I just want to filter out the bad gases before they hit the manifold... do you think my first option with T'ing in the 2nd valve will cause any probs? That 2nd Valve expelled a fair bit of oily steamy gas when i had the breather on it... nearly made me question if i had the right valve hooked up...
 

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I used the IM pcv nipple for a bov vacuum source before, It may even be on a few pictures I posted of my engine bay somewhere. While it did make the bov work, it DID NOT let it function properly. Not sure what the difference with that nipple is but it didnt work for crap. Im clueless why a breather filter on one side and the pcv valve side normal didnt work, thats strange. I would say try to Tee them and see what happens. Hooking them up stock would definitely not work because the boost will close the pcv valve causing a pressurized crankcase which would be a very bad thing....
 

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when i disconnected the pcv from te i/m and let it vent to the atmosphere i had really bad blowby when i sit at idle for 1 minute it would puff smoke like a damn chimney, i tried to connect it to a cetchcan from getting vacuum from a nipple before the turbo and putting that to the cetch can and tot he crankcase. It didnt work it would smoke real bad. I really wish we knew how to setup the pcv to vent properly without creating a boost leak.
 

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I dunno why mine dont give me trouble lol
 

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Discussion Starter #10
Okay, I have to settle this issue once and for all...

I looked round the net and found a diagram how the system is meant to work. It shows that the PCV draws out gasses but the 2nd valve if a car has one is to get air into the crankcase to circulate the air in there and get crappy air out... thats what it looks like...

So either tomorrow or over the weekend i'm going to keep the PCV > catch can > intake side of turbo like i used to. And with that 2nd valve try to fit it to its stock location which was under the throttle body so that way boost can go in it (the pcv can pop open with air in there)...

I'll post back with what i find unless anyone has a better idea before then...?
 

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for what it's worth, i have both of my crankcase vents t'd together to a catch to ambient air / filter. i'm also not a mechanical engineer, so i dont know if it's damaging anything by not sucking air out of there, but the general consensus from who i've asked is "i dont see why it'd be bad". time will tell.
 

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I wouldnt say that teeing them is going to be fatal to your car, just cause a bit more buildup in the in the crankcase (which running seafoam or something once in awhile would solve). The 2nd valve does not always pull air, it pushes it under load I believe. Check hmaservice.com for diagrams it shows you what they are doing under load and without load....
 

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Discussion Starter #14
Thats right, air goes into that valve to help push gas out of the other one... at least thats what various diagrams have shown me...

Havent had the chance to test it but over the weekend i definately will.
 

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Discussion Starter #15
DAMNIT!!!

It didn't work! It still puffed some smoke out! I even tried hooking the 2nd valve to the intake manifold directly (so i've tried it hooked up in every location now!) and it still didnt work right!!!

I need ideas guys!

The PCV should work fine hooked up to the intake side of the turbo shouldnt it? Omg said it wouldnt and i see that maybe there isnt proper vaccuum there but where else would i get it on WOT? Not the intake manifold cos its getting boost then... only when the TB is closed does it get Vaccuum... AHHH!!! It's sooo confoosing!!!
 

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I say it isnt your PCV causing your smoking issues as it smokes when your changing gears not while the motor is under load.
I would suggest you change oil change to see if this helps your issue as oil thats too thin seaps through worn oil seals on turbos, valve stem seals, piston rings etc.
 

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Discussion Starter #17
It doesnt just happen when changing gears, mainly when backing off from high loads... Changing gears is backing off for a second in the change but yeah...

I managed to stabilise the problem, but its not going to stay this way. I need a better more permanent method. Basically i have PCV > Catch Can > Intake before turbo and the other just has a hose coming out going to atmosphere... it doesnt like a breather filter chucked on... where can i hook this hose to!?!?

I read that with my setup i could remove the PCV and replace it with a threaded nipple thing cos the PCV is just a restriction in this case and there is no chance of boosted air going in this way... might try change it over on the weekend.

I also read that my previous setup is only good to round 5-7 psi of boost and mine i guess is properly tuned for it so thats why it failed when it did... i dunno

Do you guys think i could hook the 2nd valve to the intake with a check valve in it so it sucks on closed TB (since there is now vaccuum)? i notice the hose smokes on idle but that really doesnt mean anything...
 

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Discussion Starter #18
OK I GOT IT!!!

I did some more researching and i found this awesome method that shouldnt fail!!! I cant try it till the weekend but it goes like this:

PCV (or just the nipple and a check valve) > Oil Catch > Turbo Intake

2nd Valve > Check Valve > (One day a 2nd oil catch) > Intake manifold

Doing this ensures there is vaccuum on high load (from turbo) while blocking boost from the intake (by the check valve) and also ensures great vaccuum is used from the intake manifold on idle while blocking off the turbo intake (by the check valve and PCV) to ensure there are no leaks...

I heard this setup works great and i cant wait to chuck it in!
 

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tell me how it turns out, i tried different ways too, i get bad smoke when i shift from 1st to 2nd hard also on the dyno when they let off the gas i geta puff of black smoke
 

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Discussion Starter #20
I've only ever had white smoke come out when this happens since its attributed to oil... I always thought black smoke was due to fuel, either too much or tuning issues or somethin...

I'll definiately post back with my findings...
 
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