N75 valve

[joesgti]

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 

[tony_danza]

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.

[markymark]

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.

[vRStu]

Bolted to the Turbo housing.

[markymark]

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.

[joesgti]

so what does the N75 actually do? just trying to undersand how it all works with each other.

[vRStu]

This goes back to my earlier comments in another thread - If you run a modded car you should have VCDS in your toolbox.

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

[joesgti]

This goes back to my earlier comments in another thread - If you run a modded car you should have VCDS in your toolbox.

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?

[WhiteGTI]

Good question Joe, I am also intrigued by this N75 thingy, as I've heard it mentioned a lot of times.

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]

 

Huh?! 

[vRStu]

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.

[vRStu]

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.

[joesgti]

that thred wasnt too helpful, it was you and robin disagreeing about vagcom 

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?

[vRStu]

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.

[joesgti]

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?

[vRStu]

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.