n75 valve problems

mattfas

Active Member
Apr 6, 2009
97
0
leeds
since having my car remmaped its been playing up when accelarating in 5th or 6th gear the boost starts fluctuating i can hear the tune of the turbo changing as well it doesnt seem to be holding a constant boost i have tried unplugging the MAF but its still the same i have also checked around the tip pipe for splits or holes im starting to think its the n75 valve isthe n75valve the one with the 3 small pipes going into it located near the dump valve on the AUQ engine im looking into buying a new n75 to see if it will cure my problems wich would would be best n75 to get with my car been remmaped can i fit a standard one or is there an upgraded one for the remmaped engine any help will be much appreciated so far ive changed the coil packs and the spark plugs im at the end of my tether with this problem
 

mattfas

Active Member
Apr 6, 2009
97
0
leeds
i could do with ordering thenew one asap so wich one do i need the standard one or the upgraded one my car has stage 1 remap
 

Ronin225

Active Member
Jan 17, 2008
4,652
22
Worcester
Yes connects to TIP by DV.
Heard some people running race N75s or different version sometimes have problems, so best to go OEM.
Have you ruled out MAF, boost leak in smaller pipes?
 

mattfas

Active Member
Apr 6, 2009
97
0
leeds
i unclipped the maf earlier today thenwent for a run downthe motorway its still doing it there must be a leak somewhere the only thing is the pipe tat goes on top of the dump valve is connected with a tie rap because i cant get a jubilee clip to fit on it could this be the problem it feels like its on there good it doesnt pull off or anything
 
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mattfas

Active Member
Apr 6, 2009
97
0
leeds
i spoke to someone from awesome gti today i told him what was happening and he reckons theres a boost leak wich other pipes are there to check apart from the tip and the small one coming off the top of the dump valve
 

Ronin225

Active Member
Jan 17, 2008
4,652
22
Worcester
remove the engine cover and just check all small vacuum pipes, including the 2 that go to the LH underside of the inlet manifold
 
Dec 6, 2008
612
0
Shropshire
I had a similar thing with mine after remapping, in the higher gears could feel a light pulsing and the turbo whistle dropping off and back on with it.

Changed the N75 for a J type one on Will @ P-torques advice which seemed to sort it. But somebody else did mention that the same effect can be achieved by agjusting the small screw on the bottom of the stock one, just do it in small increments and check the results to see which way to go.

If you change for a different type then check that the new valve has the 3 ports in the same orientation, I didnt notice them the wrong way which caused me issues until I realised.
 

mattfas

Active Member
Apr 6, 2009
97
0
leeds
ok mate cheers im going to go round all the pipes tommorow and try find the leak and if i cant ill go for the new n75 are they hard to fit how much and were did you get yours from
 
Dec 6, 2008
612
0
Shropshire
ok mate cheers im going to go round all the pipes tommorow and try find the leak and if i cant ill go for the new n75 are they hard to fit how much and were did you get yours from

I actually got mine from ebay but its a genuine vag one (or seems to be lol) was about £60, is easy to fit but one of the ports is longer than the other 2, it needs to be installed the same way in relation to the ports as opposed to the plug connector.
 
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