Change PCV Valve, now getting rough idle

[Chr1sJohnson]

Here I go again with another weird one. I decided to change my PCV valve thinking it could be what was causing some of my boost leak (it was the stock part from 2007, and i've heard on the forums that these tend to go bad and can cause a decrease in boost). I went and bought a brand new one from worldpac and installed it and now I am having a very rough idle, yet smooth power delivery under load. After reaching out to APR, I just found out that apparently the new PCV valve that I just purchased is not the correct one, which is what is causing my rough idle issues. See the picture below as a reference to what the correct PCV valuve should look like. Do these go bad?

I did somehow create an additional 2-3 PSI than I was before with this new but wong PCV valve... APR suggests that obviously purchased the correct PCV valve, or their catch can system.. then they want pressure test everything again and look for leaks, and turn the PSI up to 30 very carefully.. I only went up to 11-12 previously... I just didn't want to cause any damage by cranking it up too high.

I started another thread a couple weeks ago regarding some issues I was having with not being able to boost over 16-17 PSI using an APR Stage 3 Kit installed in my B7. I've had various things to try and I seemed to exhausted everyone's advice at this point.
-------As a recap, I have the new revision Diverter valve and inspected it again and noticed no tears, etc.. I did a boost leak test and noticed smoke coming from around the seal of the turbo so I separated the turbo added some RTV, resealed, did another boost leak test and was good to go. I drove the car and under my first hard pull I got up to 25 PSI and climbing until I eventually blew off one of the inlet hoses connected to my intercooler. I pulled over turned the car off to fixed that, went to drive it again and noticed that I am boosting slightly better than the initial 16-17 PSI that I was before, but still won't go past 20.


Here are the details from the logging I did. I went off of the APR instructions and did 4 different pulls from 1500 rpm rolling in 3rd gear up until fuel shut off... I also and including a picture APR just sent me basically showing me how my car is underboosting. The BLUE line is engine speed (climbing as the pull occurs), the ORANGE line is the specified boost pressure and the GRAY line is the actual boost. Notice, actual never gets to specified. You have a boost leak somewhere. I also included the actual .CSF screenshot of the DATA I pulled from Vag Com using the APR instructions.

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[atvhead]

You need to make sure you only have one check valve in the system. Either one in the turbo pipe or one in the top one. Can't have it in both or missing from both.

[Okedokey]

Yeah, either both upgraded parts (later revisions) or both previous revisions.

[rongeur]

Your fuel actual is not keeping up with the specified. APR is calling for 129 but I believe unless you graded the PRV to RS4 valve, it may be cracking open preventing the called for fueling. Boost actual is not keeping pace either.

[Chr1sJohnson]

Your fuel actual is not keeping up with the specified. APR is calling for 129 but I believe unless you graded the PRV to RS4 valve, it may be cracking open preventing the called for fueling. Boost actual is not keeping pace either.

Would it benefit me getting the APR Catch Can system - http://www.goapr.com/products/catch_can_universal.html.. Think this would resolve many of my issues?

Or are you thinking that I should just go with upgrading to the RS4 PRV valve - http://www.uspmotorsports.com/Engine...ase-Valve.html
Would that even work on my car?

As far as my boost actual not keeping pace, what do you suggest I do?

[Chr1sJohnson]

Just to update this thread -- I resolved my boost leak. I ordered a new PCV Valve w/ Check Valve, new updated aluminum corrugated pipe WITH check valve, New N75 Valve and all new vacuum lines for the N75. I was boosting 16-18 PSI (never consistent in 1st gear) I am now up to 24-26 PSI in first gear. The power has returned and it cost me under $200. Thanks ECS Tuning for the parts, and appreciate the advice on this one. Next step is the Oil Catch Can system from ECS Tuning or APR to eliminate this happening again.

[Chr1sJohnson]

You need to make sure you only have one check valve in the system. Either one in the turbo pipe or one in the top one. Can't have it in both or missing from both.

I ordered the PCV Valve with the check valve and the one for the turbo pipe without and still wasn't boosting as it should. APR suggested that I order a new aluminum corrugated pipe WITH the check valve, and keep the PCV with the check valve.. and not sure why, but this resolved all of my issues (on top of the new N75 and vacuum lines)

[Endmass]

Not to Hijack:

Car's been rough running since I replaced the stock PCV, first with a BSH redirect kit, and now with the 034 catchcan.

Problem is I've done a lot more than just the PCV, all at once - and I'm not sure it's just the pcv.



So, 034 kit, no check valve in the system: could this be the issue?