PCV failing?

[NickMk61]

So, its been about a week after I got my stage 2 tune, and I've noticed that my rpms aren't jumping up like they did when I first got the tune. So, naturally, I contacted my tuner and told him what was going on.. it wasn't a drastic powerloss, but I could definitely tell that something wasn't right.

He told me to idle my car and slowly open the oil filler cap, and if there was a hard vacuum type suckage on the cap that my PCV valve would be failing.. So I did what he asked, and it wasn't necessarily a "hard" vacuum, but it was noticeably sucking the cap back down. now ill be honest I don't know much about specific components, such as a PCV valve.. but would this be the culprit for what I'm experiencing? I don't have a CEL, and it still feels like I'm pulling harder than stock, but compared to what I experienced a few minutes after I got the tune, it feels more like a boosted stock than a stage 2...

anyways, if you guys have any info on this. please let me know! Thanks!

 

[Gti For Me]

If your PCV system fails you would have fault codes for fuel trim lean,misfires,idle fluctuation and some others.If you take off your oil cap it is normal to suck in vacumm,if it didn't pull vacumm then you would have a problem.

 

[Connor19]

Scan the ECU, if a code comes up and says "FUEL RAIL PRESSURE TOO HIGH" or something along those lines then you have the same problem that i had, it's something with your HPFP, If you're experiencing power loss, muffled exhaust and some rpm weirdness, take it to your tuner and have them clear the code and all the power will come back instantly, if it starts to lose power again you would need to work with you tuner/dealership about whether it's the HPFP itself or the wiring harness of the HPFP, it could be either one

 

[McQueen77]

If your PCV system fails you would have fault codes for fuel trim lean,misfires,idle fluctuation and some others.If you take off your oil cap it is normal to suck in vacumm,if it didn't pull vacumm then you would have a problem.

yeah whoever told OP that the vacuum is a sign of PCV failure doesn't know what they're talking about

youd have codes all over the place if it were failing.

 

[GTIMKV20]

Did you swap in some new coil packs and sparks for good measure? I'd start here. MKV had PCV issues but I have yet to hear anyone with a TSI and PCV problems.

 

[2013R]

99% likely in your head. always turns out that way. you dont have a bad HPFP.. if you did, the car wouldnt even rev past 4000rpms. it's called getting used to the power.

 

[NickMk61]

99% likely in your head. always turns out that way. you dont have a bad HPFP.. if you did, the car wouldnt even rev past 4000rpms. it's called getting used to the power.

yeah I know, I was thinking that it probably was in my head... but I'm getting some pretty noticeable turbo lag.

I was driving around tonight and when I would go WOT it would kinda take a while to boost and the rpms wouldn't jump up like they would right after the tune... Going from stock to stage 2 is a pretty dramatic difference so I can remember pretty vividly how crazy the power was.. but this isn't throwing me in the back of my seat like it did the first time.. im going to get it all checked out in the morning to be 100% sure. we'll find out tomorrow if I was just imagining it all

thanks for the input guys.

 

[mg_90]

I had my PCV replaced under warranty with only 5400 miles on the car. The rpm dropped suddendly at a stop or traffic light and idle was really rough also I wasn´t getting any CEL.

 

[NickMk61]

turns out that I had an old diaphragm bypass diverter valve which had broken somehow and had oil all over it when removed.. had it replaced with the new upgraded piston diverter valve.. it does feel more responsive, but for some reason still doesn't feel like all the power is back... I've also noticed that when the weather is 75 or cooler the car REALLY wakes up.. like dramatically compared to when its mid-day and 80+ outside here in Houston..

 

[2013R]

turns out that I had an old diaphragm bypass diverter valve which had broken somehow and had oil all over it when removed.. had it replaced with the new upgraded piston diverter valve.. it does feel more responsive, but for some reason still doesn't feel like all the power is back... I've also noticed that when the weather is 75 or cooler the car REALLY wakes up.. like dramatically compared to when its mid-day and 80+ outside here in Houston..

just wait till a 40F day..