Boost leak-strange or not?

[Greg_S]

have a search for p/n 035103245A on ebay...theres loads on there at around £7 a pop

Where does it fit in the PCV side?

[mike74]

Under the throttle body, in the rats nest of wires and pipes
a right beeatch to get to, especially if the original audi pipe clamps are still there

[newsh]

Find the carbon can valve and follow the pipe forward.

[newsh]

Here you go, the one way valve is hidden in the fat side of this rubber T piece.

[piotr]

It can also leak past the turbo seals and make that bubbling sound, in which case leak test from the turbo output hose.

This is how did the test-from the turbo output hose

[newsh]

In that case you haven’t pressure tested your Wastegate or N75 piping or the PCV system (apart from the one way Valve which must be working ok or air would be escaping back into the MAF hose!)
It was assumed you’d tested from the MAF hose.

[piotr]

No -i did it from turbo hose where it charges in to the intecoler etc as Mark said this is the way to do it .

[adam g]

Can anyone advise how long it should take the boost to leak away. I thought a minute was about typical. Won't pressure get to the crank case anyway by going passed the piston rings.

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[piotr]

Can anyone advise how long it should take the boost to leak away. I thought a minute was about typical. Won't pressure get to the crank case anyway by going passed the piston rings.

Sent from my D5803 using Tapatalk

I would like to know that as well as im not sure if my symptoms are definitely fault or not.my boost cut is definitely related to increased turbo boost.when i release some pressure of the WG spring it drives ok with no boost cut,as soon as i screw the bolt in on WG it will start cutting.

[newsh]

Can anyone advise how long it should take the boost to leak away. I thought a minute was about typical. Won't pressure get to the crank case anyway by going passed the piston rings.

Sent from my D5803 using Tapatalk

Leaking away over a minute or so is fine. As you say there will be some small leakage past the rings.

You need to check your PCV system for leaks though, and the WG pipes and diaphragm.

[newsh]

I would like to know that as well as im not sure if my symptoms are definitely fault or not.my boost cut is definitely related to increased turbo boost.when i release some pressure of the WG spring it drives ok with no boost cut,as soon as i screw the bolt in on WG it will start cutting.

Is your car mapped using the car’s Motronic ECU to control boost or did Mark use a boost controller?

[piotr]

Well ,the safety overboost cut off limit is controlled by ECU (stock)but N75 is not doing its normal job as Mark dont like them.Its blanked off now and pipe runs between turbo and WG - this is how it is controlled.

[newsh]

I thought this might be the case. This is very important info for anyone trying to help, without the N75 the ECU can’t control boost, only cut fuel if boost max is exceeded. What’s the boost pressure when it cuts?

Check the pipes from the turbo to the WG for leaks, check the WG diaphragm. You can do this with a Mightyvac.

Check the PCV system by the methods I described above, I can lend you a bung for the MAF hose.

[piotr]

Briliant-i will check all that when im back from holiday-thank you for that.Now i have got plan what to do when im back