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2014 VW GTI w/ Rough Idle ***NEED INPUT***

virtualbong

Passed Driver's Ed
Hi everyone,

My GTI had a Check Engine light a couple of months back but I resolved it by cleaning the MAF sensor. Unfortunately, the Check Engine light came back and it is much worse now. Before I take it in to a mechanic to diagnose, I would like to try to save myself a lot of money and troubleshoot and resolve on my own. I would love everyone's feedback on whether or not they have experienced this issue before and how you resolved it. Here are some details, pics and video.

Car Details
Year = 2014
Vehicle = VW GTI Driver's Edition 4-Door
Miles = 150,000+

Recent Issue
Back in October of 2019, I received a Check Engine light with an error code stating lean on Bank 1. I bought some MAF cleaner and this did the trick. Note, this was when I had the stock air intake. Since then, I have swapped out the stock air intake for a Unitronic CAI. I had no issues for around 4,000 miles of driving after CAI was installed.

New Issue
Check Engine light came on a couple weeks back and the car started to have a rough idle. I kept driving on it because it seemed to be ok for most of the time, but it has gotten really bad and now the engine lurches and the idle goes from 1,000 RPMs to 2,500 RPMs and back down. It also has stalled recently just driving it into my garage to check out the seals.


I ran an OBD sensor and received the following codes:

P2279
IMG_2460.jpg

IMG_2463.jpg

P2187
IMG_2461.jpg

P0507
IMG_2462.jpg


Steps Taken So Far
1. I initially cleaned the MAF sensor again, but that did not resolve the issue
2. Purchased a new MAF sensor but the check engine light did not go away and things seemed to get worse

Potential Issues After Research
PCV Valve Malfunction
Two things make me believe this may be the potential culprit.
1. During my install of the Unitronic, I accidentally broke the tab to the connector of the rear breather hose. I zip tied it and it looks secure but that may be where the vacuum leak could be coming from
2. I believe the PCV Valve is broken because it looks to be an oil leak right at the bleed hole (pics below)
InkedIMG_2495_LI.jpg


After reviewing the summary of my symptoms of a rough idle and my troubleshooting steps, what are people's thoughts on what could be wrong? Do you agree or disagree with my outcome?
I have already purchased a replacement PCV Valve with both breather hoses on Amazon so they should be arriving on Friday. I can return the kit for free if someone believes I am way off and the codes are a result of something else that needs to be resolved. Any help would be appreciated. Thanks VW community!
 

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csumt76

Go Kart Champion
Sounds like you're on the right path. Any air leak beyond the maf could cause this. If you can't hear or locate any obvious leak, you can use a small squirt of brake cleaner in suspected areas.
 

virtualbong

Passed Driver's Ed
Sounds like you're on the right path. Any air leak beyond the maf could cause this. If you can't hear or locate any obvious leak, you can use a small squirt of brake cleaner in suspected areas.
Thanks for the guidance man. I did try the whole carb cleaner method (slightly scary with all of the videos stating that the engine could get on fire if there's any spark) but I didn't seem to find a difference in the idle after spraying in suspected areas...granted, I may have not sprayed enough because of my hesitation to spray too much.

I was going to uninstall the whole intake system but I really don't think there is any issue with the connections post MAF to the turbo. It seems pretty tight at all connections except for the breather hoses...

I would still love some type of confirmation that the PCV Valve is faulty and there truly is some oil leak.
 

csumt76

Go Kart Champion
Yea I always used brake cleaner, not carb cleaner for that reason. Another thought maybe if you had some vacuum caps lying around you could temporarily delete the pcv to try and verify.
 

virtualbong

Passed Driver's Ed
Yea I always used brake cleaner, not carb cleaner for that reason. Another thought maybe if you had some vacuum caps lying around you could temporarily delete the pcv to try and verify.
Is that the message described in this video by humble mechanic?


Basically, cover the hose in the front?
 

virtualbong

Passed Driver's Ed
Is it as simple as me just putting electrical tape over the opening? Sorry for the ignorant question...I just don’t want to mess anything up
 

csumt76

Go Kart Champion
Yea whatever works as long as it will seal and you don't let it get sucked into the engine. Elec tape may have a hard time sticking to it... You could pretty much jam anything to block the hole while you start it(only to test) Rag, zip tied plastic bag, rubber plug, your finger if you have a helper, bratwurst lol
 

virtualbong

Passed Driver's Ed
*** 1/3/20 UPDATE ***
Late on posting this but decided to post to close out this thread.

I decided to go ahead and replaced the PCV Valve as well as the front and rear breather hoses. Since the replacement, the car is back to a normal idle. FIXED!

Here is where I purchased the replacement on the cheap!

VW GTI MK6 PCV Valve Replacement w/ Hoses

I do have one gripe though. The rear breather hose was a pain in the butt to install. I believe the plastic is slightly larger which made it difficult to completely install. I had to zip tie it to ensure it won't come out but there does not seem to be any vacuum leaks so I'm good for now.

I also wanted to talk about the install. Removing the ignition coil connectors were much tougher than I expected. I actually broke one of the clips. You definitely want to be careful about how you remove it. Use the technique of pressing back on the tab but then pushing it forward at an angle to get the coverage you need from what is holding it in place. Here is the video I used.

Here is the install vid that I used for this work.

Here is a vid on how to remove the ignition coil connectors

Let me know if anyone has any questions.
 

snobrdrdan

former GTI owner
Glad you got it fixed!

It's your car, but most people recommend and have had better luck with the OEM/VW PCV. Last thing you want is that "cheap one" to fail, because you didn't want to spend the extra $100, and then you're pulling the trans and replacing the RMS for A LOT more than that.
 

virtualbong

Passed Driver's Ed
Glad you got it fixed!

It's your car, but most people recommend and have had better luck with the OEM/VW PCV. Last thing you want is that "cheap one" to fail, because you didn't want to spend the extra $100, and then you're pulling the trans and replacing the RMS for A LOT more than that.
I’m interested to learn about the difference in failure from oem vs. aftermarket? I would consider purchasing stock if I knew that the issues with the pcv valve have been resolved and if the aftermarket’s failure is worse than stock. If not then I think it’s a good alternative in the meantime but definitely let me know If you have heard of major failures from these aftermarket ones that are different from stock.
 

snobrdrdan

former GTI owner
Thread right here:
 

virtualbong

Passed Driver's Ed
Thread right here:
I did notice that thread but I thought the oil leaks was due to bad rear main seal and potentially human installation errors.

In the end, I do agree that oem will almost always be a better choice but knowing that the oem still was not perfect, I went with the cheaper alternative. I wanted to replace the hoses as well and for $48 shipped for everything...I was willing to take the chance. With that said, I will be keeping a close eye on things to ensure I don’t get a massive malfunction.

appreciate all the input. Love the community and willing to help.
 
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