A little help please

[nannuk321]

Hi there New to this forum so bear with me please. I have a mk1 cupra 180. I bought the car about 6 months ago and absolutely love it. The guy I bought it off told me it had been remapped and now it's 213hp. I have a full service history but no record of this, all I know is it goes like stink and has a pillar mounted boost gauge. Lately though it has started to play up. Some days I get in it there is less than quarter of the boost. I can put my foot to the floor and hardly anything. This usually happens when it's been sitting for a few days. I will get where I'm going but on my way home it's fine. Full boost. Also before this when I was at half throttle the needle on the boost gauge would be fluctuating and I could hear the turbo doing the same. Dose all this sound familiar to anyone? Any help would be much appreciated
P.S. It has a forge dump valve. Don't know how old this is.

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[Bigjohn84]

How much boost is it reading? Sounds like ur n75 valve is about to go

 

[nannuk321]

Hey Thanks for getting back to me. When it's playing up its actually just about 0

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[nannuk321]

Above 0 I meant to say

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[Bigjohn84]

Basically no boost atol then, N75 valve is prob shot

 

[Bigjohn84]

When the car isn't moving it will say -30 or whatever is on the guage when you start driving normal say 30mph it will be at 0psi or just above, when you stick ur foot right down it then goes up, I get 19psi of boost and no more

 

[nannuk321]

Aww thanks for that. I'll get one of those. Just googled it and it looks as I might be able to change it meself!

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[Bigjohn84]

Yes easy enough to change, before you buy one take urs off and at the end of the numbers is a letter make sure u buy the same valve with same letter, I normally sell them but I've none just now

 

[nannuk321]

Thanks for that. I'll make sure

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[Bigjohn84]

While you do that give your throttle body a clean

 

[nannuk321]

Will do

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[Bigjohn84]

Look for spilt hoses also these car get boost leaks, best and cheap way is to get a spray bottle of soapy water and start the car and spray on the pipes then watch, good luck

 

[nannuk321]

Thanks mate. Will give that a try

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[Kako51]

Im having the same problems,got full boost one minute but turn car off go to the shop and find boost isnt holding at all replaced n75 valve but it hasnt changed the way the boost alternates at all,great idea from bigjohn84 will give it a go tomorrow