Golf 1.8t 150 boost problem?

[20V TURBZZ]

Hello, I was driving my golf today and thought i'd give her some stick. Anyway it boosts fine around 10psi at 2.5k rpm and holds it all the way to 5000rpm then it feels as if the wastegate opens and boost drops instantly to zero then fluctuates from 10 till 0 repeatedly after this there is a horrible smell. i have looked everywhere for an answer and have read on a few different sites people saying they dont rev past 5 without the wastegate opening but i find this hard to belive?  any help will be appreciated. (it has not been mapped just a mcb set to 10psi and a pipercross pannel filter) cheers

[20V TURBZZ]

Also no engine management lights??

[Chris.]

Does it do the same with no boost controller?  Whats your engine code?  is the N75 still plugged in? Is the piping right?

[20V TURBZZ]

I bought the car with the mcb, but i have put the n75 valve on and it boosts to 7 and is pretty much at 0 by 4000rpm? all piping is correct as i have checked with a friends car. The n75 is currently unplugged. could it be a boost leak, and the mcb is hiding this by not opening the wastegate? thanks

[20V TURBZZ]

and its AUM by the way.

[Chris.]

Put your n75 back in and does the problem go away.

the engines ECU will be taking a fit not being able to regulate the boost so it drops into limp mode by shutting sensors down to low power.

[20V TURBZZ]

Okay il give it a try but with the n75 valve it only boosts to 7 and is pretty much at 0psi by 4000rpm so i wouldnt be able to find out? this cant be correct either, could it be a faulty n75?

[Wayne]

Okay il give it a try but with the n75 valve it only boosts to 7 and is pretty much at 0psi by 4000rpm so i wouldnt be able to find out? this cant be correct either, could it be a faulty n75?

Has the car been remapped, if not around 7psi is standard.

[billythegolfer]

I have just found this thread, mine is exactly the same, boost, drop off, boost, drop off, really strting to annoy me.

Havent had a chance to check all my pipes but would you guys recommend checking the N75 firstly?

Thanks in advance and sorry to hijack your post.

Billy

[danny_p]

engine managment light won't allways come on.  on the passat the wastegate fell apart and the valve head got wedged in the exhaust turbine causeing the turbo to genade.   no engine managment light no fault codes   no boost ether