PCV valve leaking?
 

I put a check valve between my intake manifold and pcv valve this afternoon. i did it as a precautionary measure, so that boost pressure wouldn't be pushing back against the pcv valve, and because i've read that they can leak boost. I've never used one in the past so this is my first time trying.

After i installed it and went for a couple WOT runs i noticed my peak/warn boost gauge was flashing red at me. uh oh. the warning is set at 8.5 psi, and the recall said that's what i hit. the car has a hallman pro mbc, but it's set all the way out, running off of (7psi) wastegate spring pressure. prior to this, i would peak at around 7.5psi or so. Call me crazy, but it sounded like the turbo was working less hard under boost as well, like less intake sound. That part may be my head messing with me, but i swear it sounded different lol.

Also, my breather just vents to air until i can find a good catch can solution, and before i would notice a bit of oil accumulated at the bottom of the hose. after the run with the check valve there wasn't any oil there.

i think this means the pcv valve may have been leaking boost. am i crazy? stupid? correct, maybe?

or all the rain and temp drops are causing normal spiking which is common with manuals. try it again tomorrow when its warmer outside before jumping the gun

good call. it was definitely cooler today than it has been for a while.

The price is so awesome!!!

Yeah it is! Great find @jamesm :thumbsup: I thinnk it's a good idea for everyone thats boosted to run one on the manifold side.

Can you take a pic of your setup, so I can get a visual on how it is setup? I do agree that especially with MBCs your boost can easily change by 1 psi from day to day.

sure, i'll take one on my lunch break and post it up. it's a really simple setup.

If you take the stock PCV valve out of the block and blow through it, 1 human lung air pressure is enough to blow air by it. It's why we started supplying upgraded in-line metal turbo pcv's with our breather tank kits for the stage 2 builds.

here is a pic of how i have it installed. it goes between the pcv and the intake manifold, with the flow in the direction of the manifold. if you had a catch can on the pcv line, you'd install it between the manifold and the catch can, again with the direction of flow towards the intake manifold.

https://sphotos-b.xx.fbcdn.net/hphot...89737553_n.jpg

sorry for the cell phone image quality.

my belief is that it had to be leaking. the hose that connects to the pcv has no zip tie or anything holding it on, and it literally fell off in my hand, very little tension holding it in place. if there wasn't a leak you'd think that line would've blown off under boost pressure by now.

i drove the car this morning and it is still running higher boost than before. also, it definitely is making a lot less turbo intake noise. my wife even noticed it.

not sure if it was an issue before, but it definitely isn't now with the check valve. i'd recommend them to anyone in either case, peace of mind for $1.

I think that should work well. Interesting location for your MBC as well.

ok so today it's back to the regular florida hot-as-balls weather same as before, and i just hit 9psi and threw a 'fuel system too lean' code. my fuel trims are all over the place now. i'm pretty convinced the pcv was leaking boost at this point.

Yikes! Does it need a retune then?

Yeah I'm going to baby it to rev works and their tuner is going to look at it tomorrow. It's already scheduled for a retune after the clutch is broke in (next Tuesday) when we'll up the boost. So he'll probably just make sure it's safe and make whatever minor tweaks are necessary until then. Thank god my shop/tuner are nearby lol.