MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: joesgti on March 09, 2009, 10:53:12 am

Title: N75 valve
Post by: joesgti on March 09, 2009, 10:53:12 am
what is it?

where is it?

has anybody experienced any problems with it?

how much to replace it?

Reason im asking is my cars still not right, ive got the forge service kit in the post this morning, so will take that off tonight and fit new spring and washers but gaz was telling me that it may be something to do with the N75 valve.

Also my turbo completley cut out yesterday on my home from UD and boost wouldnt go past 0psi on my boost gauge. so whilst travelling at 70mph i turned the ignition off and back on (whilst rolling) and everything was fine again.

i really am stuck with this. will try the DV tonight but if its not this then i need to find my next week spot. (which may be this valve)

cheers for any info  :smiley:
Title: Re: N75 valve
Post by: tony_danza on March 09, 2009, 10:56:48 am
Dunno about the N75 valve, someone will know where to find it.

The car sounds like it went into limp mode ... probably as the boost levels were up the spout, the ECU coudn't make sense of it and just shut down into safe mode. I wouldn't worry too much about this, just get that Forge thing done and see from there.
Title: Re: N75 valve
Post by: markymark on March 09, 2009, 10:58:44 am
I dont know where it is on the Golf but when I bought one for my 1.8T they were about £35, there was an uprated one which was meant to be a better option I think it was off the TT.
Check on ukmkivs as i think that is where I sold my old one and it seems to be a common theme on there!
The valve is supposed to improve the judder you used to get on mapped 1.8T's and also better responsiveness. I think the one I bought was an N75J valve.
Title: Re: N75 valve
Post by: vRStu on March 09, 2009, 10:59:39 am
Bolted to the Turbo housing.

(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi97.photobucket.com%2Falbums%2Fl233%2Fvrstu%2Fbriskoda%2FDropZone%2F20TFSi_BWA_Turbo.jpg&hash=cb7156aa3e308dc1a1bee1a5ae6f12eb5eff4130)
Title: Re: N75 valve
Post by: markymark on March 09, 2009, 11:00:34 am
As tony says it does sound like its gone into limp mode, I used to get this on my 1.8T, all you do is turn off and on again and its fine, although on my 1.8T it did used to get upto a certain speed and then kick in which was quite un-nerving especially when you were over taking.
Title: Re: N75 valve
Post by: joesgti on March 09, 2009, 11:04:21 am
so what does the N75 actually do? just trying to undersand how it all works with each other.
Title: Re: N75 valve
Post by: vRStu on March 09, 2009, 11:37:43 am
This goes back to my earlier comments in another thread - If you run a modded car you should have VCDS in your toolbox.

Quote
Control pressure is formed from the charge
pressure and intake pressure via the energised
charge pressure control solenoid valve N75. The
control pressure affects the vacuum unit, which
actuates the wastegate valve via a linkage. The
wastegate valve opens a bypass channel to
allow part of the exhaust gases past the turbine
into the exhaust gas system. This control feature
allows the speed of the turbine to be controlled
and the maximum charge pressure can thereby
be regulated
Title: Re: N75 valve
Post by: joesgti on March 09, 2009, 11:44:29 am
This goes back to my earlier comments in another thread - If you run a modded car you should have VCDS in your toolbox.

Quote
Control pressure is formed from the charge
pressure and intake pressure via the energised
charge pressure control solenoid valve N75. The
control pressure affects the vacuum unit, which
actuates the wastegate valve via a linkage. The
wastegate valve opens a bypass channel to
allow part of the exhaust gases past the turbine
into the exhaust gas system. This control feature
allows the speed of the turbine to be controlled
and the maximum charge pressure can thereby
be regulated

so do you think this valve could be my problem?
Title: Re: N75 valve
Post by: WhiteGTI on March 09, 2009, 11:47:13 am
Good question Joe, I am also intrigued by this N75 thingy, as I've heard it mentioned a lot of times.

Quote
Control pressure is formed from the charge
pressure and intake pressure via the energised
charge pressure control solenoid valve N75. The
control pressure affects the vacuum unit, which
actuates the wastegate valve via a linkage. The
wastegate valve opens a bypass channel to
allow part of the exhaust gases past the turbine
into the exhaust gas system. This control feature
allows the speed of the turbine to be controlled
and the maximum charge pressure can thereby
be regulated
[/quote]

 :confused: :confused: :confused: :confused: :confused: :confused: :scared: :scared: :scared: :scared: :scared:

Huh?!  :grin: :grin:

Title: Re: N75 valve
Post by: vRStu on March 09, 2009, 11:52:24 am
This goes back to my earlier comments in another thread - If you run a modded car you should have VCDS in your toolbox.

so do you think this valve could be my problem?

I rest my case !!!!!

Have a read of this thread from here -

http://www.mk5golfgti.co.uk/forum/index.php?topic=772.165

I'm not having a dig at you but it will become clear when you read the thread.
Title: Re: N75 valve
Post by: vRStu on March 09, 2009, 11:54:23 am
I would also add that you shouldn't be confused with talk of various revisions of N75 such as J etc as this is 1.8t stuff where there is a theory/thought that different N75's from higher HP 1.8t's will have gains or benefits.
Title: Re: N75 valve
Post by: joesgti on March 09, 2009, 12:19:40 pm
that thred wasnt too helpful, it was you and robin disagreeing about vagcom  :confused:

i dont have vagcom, i dont plan on getting vagcom as i wouldnt even know where to start.
i had vagcom in it the other day and no faults are thrown up, but i have an obviouse fault......so how would vagcom have been at all helpful in my case now?

also im wanting info in the N75 valve and what it does?! does vagcom tell you how parts work and what they do?
Title: Re: N75 valve
Post by: vRStu on March 09, 2009, 12:36:15 pm
If your car went into limp mode VCDS will have logged a fault.  There are a couple of things that it 'could' be but these are pie in the sky until you have the diagnostic check done.  You ask how VCDS would have been helpful, well it will tell you the action that caused the limp mode or at least the component at fault.

The point I am trying to make is, would you like someone to say yeah go on Joe fit a new N75, would that make you feel happier?  You'll go out and buy one, fit it and then come straight back here saying that it wasn't the problem.  You'll be £20 or £30 worse off (plus an hours labour if you don't fit it yourself) and still none the wiser.

If the Forge N75 had failed you'd have similar symptoms but how will you know - or do you just say fcuk it, buy both and hope for the best??

Like I said above, I'm not trying to have a dig at you I'm trying to help you understand that your car is a very complicated machine and simply guessing what the fault might be is not the way to fixing your problem.

And no VCDS won't tell you the function of a component, but I gave you that above.  You asked if I thought that was the fault with your car which is where I am going with this.
Title: Re: N75 valve
Post by: joesgti on March 09, 2009, 12:41:25 pm
OK, cheers for the imput stu, i understand what your saying but at the end of the day i DONT have vagcom, so would need somebody close by to have another look for me.

has anybody heard of this M75 failing on the mk5 as of yet?
Title: Re: N75 valve
Post by: vRStu on March 09, 2009, 12:44:58 pm
OK, cheers for the imput stu, i understand what your saying but at the end of the day i DONT have vagcom, so would need somebody close by to have another look for me.

has anybody heard of this M75 failing on the mk5 as of yet?

I am sure we can find somone close to you, have you looked in the VCDS register here?

Yes I have heard of the N75 failing but rarely, I have also heard of the Forge N75 equivalent that is used in place of the OEM DV fail.  Both would have similar effects would would show differently on VCDS.   
Title: Re: N75 valve
Post by: joesgti on March 09, 2009, 12:49:36 pm
OK, cheers for the imput stu, i understand what your saying but at the end of the day i DONT have vagcom, so would need somebody close by to have another look for me.

has anybody heard of this M75 failing on the mk5 as of yet?

I am sure we can find somone close to you, have you looked in the VCDS register here?

Yes I have heard of the N75 failing but rarely, I have also heard of the Forge N75 equivalent that is used in place of the OEM DV fail.  Both would have similar effects would would show differently on VCDS.   

i dont understand this, i have the forge DV. so the forge DV is also called N75? 

il have a look for the regester now  :happy2:
 
Title: Re: N75 valve
Post by: joesgti on March 09, 2009, 12:51:36 pm
nobody has vagcom near me  :sad:
Title: Re: N75 valve
Post by: vRStu on March 09, 2009, 01:16:43 pm
No, the Forge DV uses what is effectively an N75 type valve in place of the N249.  So if the Forge electronic valve had failed it would actually come up as an N249 failure in VCDS.

Where are you based?
Title: Re: N75 valve
Post by: bacillus on March 09, 2009, 01:21:31 pm
With vcds you will need to, at minimum, log your Wastegate (N75) Duty Cycle (block 118) together with your requested and actual boost (block 115) and post the logs.

Where are you based Joe?
Title: Re: N75 valve
Post by: joesgti on March 09, 2009, 02:36:53 pm
i live in the north west, in lancaster, near preston.

ballicus, i have no idea what you are talking about  :rolleye:
Title: Re: N75 valve
Post by: vRStu on March 09, 2009, 03:00:26 pm
Anyone on this list??

http://briskoda.net/diagnostics-vag-com/vag-com-owners-map/80992/
Title: Re: N75 valve
Post by: joesgti on March 09, 2009, 03:19:42 pm
yea, number #83 Preston is the closest to me, should i send the guy a PM?
Title: Re: N75 valve
Post by: vRStu on March 09, 2009, 03:39:50 pm
Yes you'll need to register there to PM. 

I have checked and he is still an active member.
Title: Re: N75 valve
Post by: SteveS on March 09, 2009, 03:48:53 pm
interesting, shame no1 has the select plus near me .lol
Title: Re: N75 valve
Post by: neg on March 09, 2009, 06:30:21 pm
The N75 on the 1.8T caused me a lot of headache's, trips to the dealer and lots of time without my car - so yes that can be a problem and arkward to diagnose.

To swap it on the 2.0TFSI though - not a quick job put it that way, and you'll need small hands and a swear jar  :wink:

Joe, think of the N75 as the boost valve.

first things first, get the faults read then take it from there but unfortunatley on this engine the N75 is not easy to swap
Title: Re: N75 valve
Post by: bacillus on March 09, 2009, 07:30:49 pm
interesting, shame no1 has the select plus near me .lol

Distance is relative...   :wink:
Title: Re: N75 valve
Post by: joesgti on March 09, 2009, 10:57:46 pm
so i found the problem  :confused: !!!

i put the car in my carage and put it on axle stands, went under, took the forge valve off, then replaced all in the rings and piston and lubed it all up,

then i went to put it on the car, put the first nut in and then the second, then realised it hadnt even been mounted in the correct position, it was actually on an angle and screwed into the wrong hole?!??. so i put in back on correctly and now my cars running sweeter than ever.  :innocent: :innocent: so cuffed i knew how to do it myself  :embarrassed: oh and i didnt fit the dv........... :confused:

all sorted now and back to 100%  :jumpmove: :jumpmove: :jumpmove:
Title: Re: N75 valve
Post by: bacillus on March 09, 2009, 11:14:29 pm
great news...   :happy2:
Title: Re: N75 valve
Post by: neg on March 09, 2009, 11:54:37 pm
I know which holes your talking about, noticed that when I replaced mine once.
Title: Re: N75 valve
Post by: WhiteGTI on March 10, 2009, 01:10:28 am
Nice one Joe, well done!  :smiley: :smiley: :smiley:
Title: Re: N75 valve
Post by: joesgti on March 10, 2009, 07:53:58 am
I know which holes your talking about, noticed that when I replaced mine once.

you think i should say something to awesome, they re-fitted it and was ment to have had a diagnostics session, and on my recipt it clearly states the that area was checked!!  :confused:
Title: Re: N75 valve
Post by: neg on March 10, 2009, 08:02:37 am
I would think so - if you paid for the session too it's worth mentioning to them at least.
Title: Re: N75 valve
Post by: WhiteGTI on March 10, 2009, 08:29:59 am
I'd defo mention it mate.
Title: Re: N75 valve
Post by: joesgti on March 10, 2009, 09:04:51 am
will give them a call now  :smiley:
Title: Re: N75 valve
Post by: tony_danza on March 10, 2009, 09:09:20 am
What did I say about not trusting them with a cement mixer?

Glad it's sorted, make sure you pull the battery again to reset all the adaptations to the new (working) set up. It'll go like stink!!
Title: Re: N75 valve
Post by: joesgti on March 10, 2009, 09:12:26 am
What did I say about not trusting them with a cement mixer?

Glad it's sorted, make sure you pull the battery again to reset all the adaptations to the new (working) set up. It'll go like stink!!

once i saw the problem i instantly thought of what you said  :laugh: :grin:

will do the battery on my dinner, cheers for reminding me  :smiley:
Title: Re: N75 valve
Post by: T88OMM on March 10, 2009, 09:43:46 am
Glad it is all sorted Joe. Now you have got it sorted go and drop them wheels off at a powdercoater, RED FTW!!!  :drool: :drool:
Title: Re: N75 valve
Post by: joesgti on March 10, 2009, 09:50:33 am
Glad it is all sorted Joe. Now you have got it sorted go and drop them wheels off at a powdercoater, RED FTW!!!  :drool: :drool:

big brakes are next, then the red wheels for summer  :drool: :drool:

you should get the CHs done yellow  :laugh:
Title: Re: N75 valve
Post by: T88OMM on March 10, 2009, 10:10:02 am
Glad it is all sorted Joe. Now you have got it sorted go and drop them wheels off at a powdercoater, RED FTW!!!  :drool: :drool:

big brakes are next, then the red wheels for summer  :drool: :drool:

you should get the CHs done yellow  :laugh:

Ahhh I see! If you are gonna get them done, give WRC Wheels Repairs a call (01772 627600) they will do an awesome job on them  :happy2: