Another strange behavior for the GTI

Carlosfandang0

Autocross Newbie

• Feb 10, 2019

• #16

Andrew429 said:

When I did the oil cap test yesterday the engine was running smooth with the cap off, however you could feel air being blown out. This morning I did it again and the engine barely stayed idling and it felt like it was sucking.

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Hmmm! The fact that you had two different results makes me suspicious of the PCV, hopefully it’s that simple.


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Andrew429

Ready to race!

• Feb 10, 2019

• #17

Me too, I did try on a tiguan and the engine stays running smooth and you can feel a suction

 

Carlosfandang0

Autocross Newbie

• Feb 10, 2019

• #18

Andrew429 said:

Me too, I did try on a tiguan and the engine stays running smooth and you can feel a suction

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With a correctly functioning PCV the car should start to run rough and even nearly stall when the cap is removed, this is because by opening the cap you create a massive vac leak, if it stays the same with cap either on or off it points to the PCV being faulty.

There should be suction, that’s normal.
You may have already seen this video, although it’s refereeing to the earlier gen engine it will give you the general idea.

https://youtu.be/hQEciqR1ST8


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Andrew429

Ready to race!

• Feb 10, 2019

• #19

I have seen that, but from seeing two different scenarios and being lost on this problem I am just going to change it. I ordered from FCPEuro when I changed it a few months ago and they have a lifetime warranty on all parts, if you send back the old part you ordered from them they issue a refund.

 

Andrew429

Ready to race!

• Feb 15, 2019

• #20

Found the issue, bad MAF sensor, unplugged it and drove around, no issues whatsoever. Also have to thank APR support for helping me trouble shoot and save me from going to the stealership.

 

Carlosfandang0

Autocross Newbie

• Feb 17, 2019

• #21

Andrew429 said:

Found the issue, bad MAF sensor, unplugged it and drove around, no issues whatsoever. Also have to thank APR support for helping me trouble shoot and save me from going to the stealership.

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Great, but that doesn’t explain the vacuum leak fault code, surely unplugging the MAF just masks the vac leak?!


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Andrew429

Ready to race!

• Feb 21, 2019

• #22

Well I put a brand new MAF sensor in, and it’s doing the same problem again.

 

Carlosfandang0

Autocross Newbie

• Feb 21, 2019

• #23

PCV! As pointed out at the start of this thread!


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Andrew429

Ready to race!

• Feb 21, 2019

• #24

I did change that as well

 

Carlosfandang0

Autocross Newbie

• Feb 21, 2019

• #25

Does it still throw the fault code?


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Andrew429

Ready to race!

• Feb 22, 2019

• #26

The GTI is finally officially fixed, went back and checked every connection, turned out to be the flex coupler between the MAF sensor and the stage 2 pipe, the underside towards the back had a big tear/hole in it, bought a new coupler, good as new. Never thought to check that.