Disabling parts of Boost Circuit on 180 Cupra...

[Mr OCD]

Hi guys,

I have symptoms of what feels like boost cutting in and out between 2000rpm-4000rpm...

So rather than throw money at it guessing I want to try and fault find by disabling parts of the boost circuit.

N249
N75
Dump valve

I want to try TEMPORARILY disabling each device in turn... can anyone help me with any guides to do this and advise me if there is anything I need to watch out for?

Cheers

Scott

 

[v-g]

Have you VAG-COM'ed it?

A DV can be checked for leaks, no need to drive without one to find it's status.

There's a myriad of hoses that can leak under the bracket in front of the manifold.

The others, I don't know enough about yet.

 

[Mr OCD]

Have you VAG-COM'ed it?

A DV can be checked for leaks, no need to drive without one to find it's status.

There's a myriad of hoses that can leak under the bracket in front of the manifold.

The others, I don't know enough about yet.

Yes... no fault codes.

How do you check a standard DV? - I thought it was a sealed item?

Will be checking vacuum hoses very carefully tonight.

 

[sicupra]

try uprating the n75
I did an car boosts loads better now.
got it from audi dealer, was bout £40.

 

[Mr OCD]

Got a part number mate?

Local AUDI is only down the road

 

[v-g]

try uprating the n75

I don't think that helps, if his problem has newly arisen. If he had no problems before, then a N75 J could give more boost.

 

[v-g]

Got a part number mate?

Local AUDI is only down the road

This is the number for the J version: 034 906 283 J

 

[v-g]

I want to try TEMPORARILY disabling each device in turn... can anyone help me with any guides to do this and advise me if there is anything I need to watch out for?

-Recently I've asked a lot of questions regarding vac/boost lines and N's.
-RobDon's throttle body thread contains air leaking issues.
-His "main" thread deals a bit with it too.
-There's much to read about N249 etc on here and Vortex.
-Google can give hints too.

Maybe you can get something out of those threads. (Sorry, no links a the moment, tired.)

I don't say that your problem is a boost leak. Could be many things.
Out of experience a boost leak throws codes, and you don't have any.

 

[Mr OCD]

Cheers mate - have pretty much done what you have said and also checked for boost leaks... next step is vagcom logging and a session on rolling road.

 

[eggz61]

did you find out what ur prob wa mate, am struggling with mine, mine does exactly the same

 

[Mr OCD]

did you find out what ur prob wa mate, am struggling with mine, mine does exactly the same

It was a split pipe under manifold

 

[mattdavies]

Do you know what pipe it was under the manifold ?

and how did you find it ?

 

[Mr OCD]

Do you know what pipe it was under the manifold ?

and how did you find it ?

Yes it was an oil breather pipe ... very common on the 1.8T engines.

Well two garages couldnt find it ...

I found it by stripping as much as I could away under the inlet manifold and then starting the engine and feeling about... it was difficult to find but the biggest giveaway was oil mist on the block from the leaky pipe!

Its a tenner to replace from dealer and a bit of a sod to fit.