Surge after throttle lift

[GrayMK5GTI]

Hi All,

Ive been reading through the forums for a while before I bought  my GTI - Picked it up last Friday 

Overall im really happy with it, coming from a history of hot hatches (EP3 Civic Type-R, Focus ST, Championship White Edition Civic Type-R FN2), I love the effortless drive of the golf and the 5dr practicality 

Anyway, i noticed that when i lift off the throttle after driving foot to the floor the car "Jumps" forward before it slows down - as if there was a delay before it dumps the boost (if that the correct term).

My old Focus ST had the same and I was told it was the "turbo Control Solenoid" getting a bit "Soggy". After reading lots of posts on DV's failing ive bought the revision D (hopefully going to try it this weekend).

Do you think it could be the DV failing, or even the N75 Valve?

Thanks in advance for your help

Graeme

[TonyZed]

Hi Graeme

I have the same problem so I hope you find a solution!!

I'm not sure what an N75 valve is, but I had a valve changed which I think was called a PCV valve. I'll try and find out what it was and let you know,I think it cost £25ish. Anyways, it didn't cure the problem. 

TonyZ

[GrayMK5GTI]

Hi Tony,

I was reading up on the PCV Valve and aparently the symptoms of that failing are a rough idle. is that what yours had?

Im hopefully swapping the DV tomorrow with it being the common failure. The N75 Valve controls the boost (as far as i can deduce). If the DV doesnt fix the problem, that will be my next port of call.

To be honest, apart from the lift off surge, the car drives fine, its very responsive, theres no missfires and the MPG is fine 

Gray

[TonyZed]

Hi Gray

I have a few issues, although the car drives fine apart from these.

Firstly, it hunts a bit, particularly when cold, in first.
Of course, it has the surging from full throttle we have already talked about. Just you and me it looks like!
Also, there is a misfire under load if you put your foot down at about 80. It doesn't seem as bad as other threads are reporting, but it is either plugs or early stages of coil packs. Of course any of these could be caused by the dump valve playing up, which sounds quite common.

I'll wait to see what your DV replacement does before I go to the dealer, but if I learn anything before, I'll let you know.

 I'm surprised that no one else has made a comment here.

Cheers
TonyZ

[GrayMK5GTI]

I replaced the DV at the weekend along with the cam follower - both looked fine desipite 38k miles 

The DV made the car feel much smoother and more responsive, and dare I say it - A little quicker 

Unfortunately the problem is still there with the surging, although not quite as noticable. I might mention it to VW when it goes in for a service.

Let me know if you find a solution

[RedRobin]

.
Wouldn't data logging with VCDS identify the problem? [says he who doesn't know how to use VCDS]

[rich83]

I can hear this on my car too... only when i 'M' though. If i floor it in gear with lowish revs and then release you can hear a surge on lift off.

Should it not do that?

[RedRobin]

I can hear this on my car too... only when i 'M' though. If i floor it in gear with lowish revs and then release you can hear a surge on lift off.

Should it not do that?

....Hearing a surge is normal, feeling a power surge/loss isn't normal.

The audible surges are even more amplified when you fit an aftermarket air intake. Nice sound I think it is too.

[GrayMK5GTI]

I can hear this on my car too... only when i 'M' though. If i floor it in gear with lowish revs and then release you can hear a surge on lift off.

Should it not do that?

....Hearing a surge is normal, feeling a power surge/loss isn't normal.

The audible surges are even more amplified when you fit an aftermarket air intake. Nice sound I think it is too.

Its more of a feeling when you lift off, the car kinda "jumps" forward. Only does it on full throttle lifts and tbh its not VERY noticable. I'm very surprised more people havent had this.