Symtoms of bad n75 valve ? 1.8t

Dan20v

Active Member
Mar 26, 2013
123
0
Kent
When I accelerate I can feel the car power on power off power on power off between 1500 rpm to 3500rpm and when I first got it it was running 18 psi now it's running 12-14 psi on a bad day and sometimes back to 18 psi very strange changed my coil packs and plugs at weekend and no change. Or maybe could this be a boost leak I can hear a hising noise when I accelerate but this is my first petrol turbo so I'm a bit new to these ? Thanks dan

And on idle the revs go up and down so slightly . Almost like when I fan cuts in the revs drop but obv the fan don't come on at that time
 
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Dan20v

Active Member
Mar 26, 2013
123
0
Kent
Hmmm there so dear to buy maybe a clean ? I do have a aftermaket come filter on it whitch csme with the car ? And i noticed the flexi down pipe is blowing a bit but not sure it was cause that . With my old cars all diesel when the air flow metter has gone i used to unplug it and if no difrent it was ghat ?
 

leoncupra2012

Active Member
Mar 7, 2012
657
5
Mines just started to this. one thing after another

If you gently accelerate, like creep it up when it gets to say 2750 - 3000 revs you can hear the exhaust note fluttering as if the accelerator pedal is being blipped... but its not? Its also lost its power to put me back in the seat, its more of a smooth power now where as before it was brutal. Mines stage 2 240bhp AUQ. Im hoping its the D/V as its got a Bosch one on it? Ive ordered a Forge. Mine has no MAF as its mapped out, no 249, no CAT, i know the coolant temp sensor is iffy. but aside from that i dont know either :(
 

Dan20v

Active Member
Mar 26, 2013
123
0
Kent
Mines just started to this. one thing after another

If you gently accelerate, like creep it up when it gets to say 2750 - 3000 revs you can hear the exhaust note fluttering as if the accelerator pedal is being blipped... but its not? Its also lost its power to put me back in the seat, its more of a smooth power now where as before it was brutal. Mines stage 2 240bhp AUQ. Im hoping its the D/V as its got a Bosch one on it? Ive ordered a Forge. Mine has no MAF as its mapped out, no 249, no CAT, i know the coolant temp sensor is iffy. but aside from that i dont know either :(
Snap mate i have lost power well i can say if i turn it on it will be great turn it off and back on it will be running **** . I going to cheek my vacuum pipes and for any boost leaks tomorrow only got the car 2 weeks ogo so not rely had a good look . Do the dump valves go faulty then ? And were is standard d.v so i csn cheek for splits ? Thanks dan
 

BEOWULF

I am BEOWULF !!!
Mar 18, 2006
1,186
0
I AM IN FRONT OF YOU
Snap mate i have lost power well i can say if i turn it on it will be great turn it off and back on it will be running **** . I going to cheek my vacuum pipes and for any boost leaks tomorrow only got the car 2 weeks ogo so not rely had a good look . Do the dump valves go faulty then ? And were is standard d.v so i csn cheek for splits ? Thanks dan
I will bet ya its ya maf sensor mate :cry:
Have you had the codes read you say the revs fluctuate at idle this is ya maf sensor. You can test for faulty maf by unplugging it and see if your car drives better.
 

BEOWULF

I am BEOWULF !!!
Mar 18, 2006
1,186
0
I AM IN FRONT OF YOU
Mines just started to this. one thing after another

If you gently accelerate, like creep it up when it gets to say 2750 - 3000 revs you can hear the exhaust note fluttering as if the accelerator pedal is being blipped... but its not? Its also lost its power to put me back in the seat, its more of a smooth power now where as before it was brutal. Mines stage 2 240bhp AUQ. Im hoping its the D/V as its got a Bosch one on it? Ive ordered a Forge. Mine has no MAF as its mapped out, no 249, no CAT, i know the coolant temp sensor is iffy. but aside from that i dont know either :(
Sorry to upset you mate there is noway you can map a maf sensor out.
 

Dan20v

Active Member
Mar 26, 2013
123
0
Kent
Okay guys cheeked all the pipes they look okay maybe a little boost leak somewhere but i get a smoke test done soon . But i unplugged the maf sensor and it threw up the traction control light and the revs broped a little but i drove it up road and it felt just as quick rely maybe no change ? Maf sensor gone then ? It has been smelling quiet fuely lately is this because the mixtures wrong or could it be the silly aftermarket cone filter ? I am buying orignal air box anyways .
 

BEOWULF

I am BEOWULF !!!
Mar 18, 2006
1,186
0
I AM IN FRONT OF YOU
Okay guys cheeked all the pipes they look okay maybe a little boost leak somewhere but i get a smoke test done soon . But i unplugged the maf sensor and it threw up the traction control light and the revs broped a little but i drove it up road and it felt just as quick rely maybe no change ? Maf sensor gone then ? It has been smelling quiet fuely lately is this because the mixtures wrong or could it be the silly aftermarket cone filter ? I am buying orignal air box anyways .
Cone filter will kill ya maf mate
like i say u are stabbing in the dark until you get your codes read :cry: thats why i got rid of my 1.8t did everything on that still could not get to run right
 
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jimcupraturbo

Active Member
Nov 23, 2013
54
0
I'm having trouble with mine as well not sure what it is sometimes it boosts and when I hit 4 to 5000rpm it drops boosts then comes back on again any ideas

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VLFPAUL

Active Member
Jul 21, 2016
1
0
Hi there just wanted to add we have been having the same issues with a leon cupra even after having stage 1 and 2 remap, new maf sensor, full de cat pipe, forge dv, air filter changed, new coil packs etc.:D. After reading a few forums we changed the N75f valve from the f to an e one that should be the proper one for our car and it seems to be running smooth we haven't done and boost tests with gauges yet but definitely is driving much better and seems to have stopped the hesitating, fluttering so hopefully this will help others.
 

RichyH

Active Member
Dec 20, 2015
290
7
Lincoln, UK
Had the same problem, replaced the maf, and now she's back to eating up the mph again, a vag garage only helped me by taking money off me, asked on here, problem solved


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RichyH

Active Member
Dec 20, 2015
290
7
Lincoln, UK
Hi there just wanted to add we have been having the same issues with a leon cupra even after having stage 1 and 2 remap, new maf sensor, full de cat pipe, forge dv, air filter changed, new coil packs etc.:D. After reading a few forums we changed the N75f valve from the f to an e one that should be the proper one for our car and it seems to be running smooth we haven't done and boost tests with gauges yet but definitely is driving much better and seems to have stopped the hesitating, fluttering so hopefully this will help others.


I changed the n75 on mine and the problem persisted, Is the maf bosch? Because mine wasnt that's why i had my issue. I may be the n75 by the way, just saying that mine wasn't


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westy989

Active Member
Nov 28, 2009
107
0
Cambridge
I had mine mapped a couple of months ago, it had a new MAF at the same time as the remap. It ran fine for a few weeks then I get the whole spooling up to about 3-4 k then boost drops off then comes back. I just fitted a brand new forge 008 today had a little go with it and it's made it worse! Now the boost drops off and doesn't return. Could this be the N75 valve ? I've checked for leaks in pipes and found none it all looks pretty good.

I'm gutted !
 

RichyH

Active Member
Dec 20, 2015
290
7
Lincoln, UK
I had mine mapped a couple of months ago, it had a new MAF at the same time as the remap. It ran fine for a few weeks then I get the whole spooling up to about 3-4 k then boost drops off then comes back. I just fitted a brand new forge 008 today had a little go with it and it's made it worse! Now the boost drops off and doesn't return. Could this be the N75 valve ? I've checked for leaks in pipes and found none it all looks pretty good.

I'm gutted !


Probably worth doing the N249 delete, stop the ECU messing up your boost after the map, have you got an LCR?


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westy989

Active Member
Nov 28, 2009
107
0
Cambridge
Yeah it's an lcr, really randomly tonight it appeared to be running fine without me doing anything except I took the plug out of the N75 valve blew it out and plugged it back in. I'm going to replaced the valve cause I still feel like I'm getting intermittent powerloss.

Don't really want to go down the N249 bypass route unless I have to.
 
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