View Full Version : Pcv vent to atmosphere question

02-21-2017, 11:09 PM
First I have done quite a bit of reading just want to verify a few things (I've also asked similar in one of my other posts in the 1.8t tech section but seems quiet over there...)

I've already deleted the SAI, N249 (I think), Suction Jet Pump and such. I intend to leave the EVAP system but would like to negate as much as possible.
When venting to atmosphere (catch can or not) you have the pancake valve attached to your TIP, runs through a hard line to a "T" on the Cam Cover which runs to the PCV (bleeder valve I believe it's called) through a T which seems to be above oil filter and from the valve is attached to a check valve and up to the intake manifold.

Could I remove the pancake and plug the hole on the TIP, remove hard line and attach a vent line to the "t" running that out of the way or to a catch can. On the Drivers Side, can I remove the end of the valve, (leave or remove checkvalve?) and just plug the port on the intake Manifold?

Is this the proper method?

I haven't decided what turbo I'll be going to come summer (273,000km on the original k03) but I will be going for a little more power so k04 or bigger (still gonna be a daily driver).

I want to do this as I've got a higher than normal idle when warmed up symptomatic of a leak sucking extra air in (currently mafless since last one failed and cause idle to jump between 800-2000 which corrected when I plugged so it's still installed but unhooked). One person said when his tip split his idle was 1200, but I can't see an external leak as at idle I'm between -18 and -21 on my boost gauge, and doing pulls it spools to 19psi and holds (not long runs but holds for close to 1000rpm increase) I start hitting positive pressure at 1500rpm. There is almost no lag building boost and otherwise it runs great (minus the exhaust leak whistle over 10psi, my fault, taught myself to weld building an exhaust for the car but it lasted almost 6 months before it started leaking).

So if that's correct please let me know and if you have any other suggestions for my high idle.

02-22-2017, 04:16 AM
Have you cleaned and re-adapted the throttle body with VCDS?

If you're keeping it a daily and just want to figure out a high idle, I don't think re-doing the entire PCV setup is necessary. What if it isn't the PCV? That's a lot of work that didn't fix your problem, and now you have a smelly car.

A high idle means you are getting air into the intake manifold that isn't expected. You can just temporarily pinch off each hose that connects to the intake manifold to see which one affects the idle. Could be your brake booster. Could be the EVAP/LDP. It could even be cracked plastic injector seats. You can usually check those with a can of brake cleaner or a boost leak test.

02-22-2017, 04:32 AM
Take walk y'all words of wisdom. I agree with everything he's said. Could be a cracked pipe in the pcv system. But definitely a leak somewhere. Have you done a boost leak test. As far as dumping the pcv, it's possible. 034 makes crankcase breather adapters with either a 1" OD nipple or one with an NPT thread on it. Hook a hose to it and fine a nice place to you it. I used the 1" adapter with about a meter of silicon hose I got from a diesel shop and routed it with a 90 off the adapter and over the driver trans mount. As far as the breather port on the valve cover, get a small breather filter and slid it on and clamp it with a hose clamp. I think I found mine in Amazon for 15$ or something. I forget the diameter you need but they make them.

02-22-2017, 01:26 PM
I just went and pinched off where the bleeder valve runs up to the intake manifold and idle dropped back down, release and up to 1000-1200 so that's the culprit, it's sucking extra air into the intake manifold from that valve but with my understanding of the system where is that air coming from as it runs from a breather to the manifold and cam cover to tip?

If it was cracked I'd have the high idle issue at all times not just when it's hot wouldn't I?

And venting to atmosphere wouldn't be much work as it'd just be removing two lines adding one and capping/plugging two ports?

I can't fix it now just posting now as waiting for my flight to work but would like to be able to address it for when I land as I've got two days before a road trip home and I'll be 4 hours from the nearest place to get parts etc.

02-22-2017, 07:55 PM
Sounds like the bleeder valve could be faulty. It should shut down the flow through valve when at idle. That's half of it's purpose - to regulate the vacuum applied to the crankcase. If everything else looks ok, I might suggest you pull the bleeder valve out and inspect it. If it's clogged up with junk and not moving against the internal spring properly, that may explain your issue.