0,4 boost, first run with the car

[Lopez90]

Thanks for the tips. Keep them coming.
tuner said he tried to bypass wastegate without any difference. MFTS disconnected is tested aswell. Will check n75click on WOT

[newsh]

10-00 - Adaption Limit Not Reached

Have you tried a different Lambda sensor?

[newsh]

Tuner said he tried to bypass wastegate without any difference.

This is interesting, so we need to know how he “bypassed the wastegate”

The pipe from the face of the turbo goes through the N75 to the WG lower chamber. With the N75 disconnected (or ECU in limp mode) the pressure from the turbo opens the WG at 0.4Bar with a standard spring in there.
If you disconnect the pipe to the WG and plug it, the WG should not open and boost will rise with turbo pressure till the ECU cuts fuel at about 1.5Bar? So that is the test I would do now, disconnect and plug the hose from N75 to Wastegate and see if you get lots of boost.
If not then there's something stopping your turbo from spinning up, either the Wastegate is already jammed open or there's a blockage in the intake or exhaust.

Also check your diverter valve diaphragm.
You should be able to pull a good vacuum on the actuator port. If the DV diaphragm is split it doesn't show in a boost leak test unless the actuator line is disconnected (easiest to do at the IM end). Split diaphragm is like a short circuit, the turbo just pumps from its output back to its input without building good pressure, can also make weird noises while driving..)

[Lopez90]

Thanks for the tips yet again! This forum has so many helpfull people.

havent changed the lambda. pulled codes last time In 2020, so i cant really remember if i did anything with those codes. We are a few people owning the vagcom together so i dont have it at my house atm.

Got the car up on my quickjacks atm, inspecting the exhaust. Have changed the front knock sensor now but havent fired it up yet. My next move will be check n75 click when WOT and Blocking the hose between n75 and WG

[Rikki Kitto]

These cars have got something special for surewhy do we do it to ourselves, good luck sorry I can't add anything useful as it's all been saidbe interesting to see what turns up

[Lopez90]

Had to adjust the exhaust so i had a look inside aswell but couldnt find anything blocking it.

swapped DV, and changed front knock sensor. Cant «feel» n75 clicking but i think i can hear the click when i rev it under the bonnet. Still no luck with boost.

I blocked the Line from n75 to WG and got boost obove 0,5!! First time since i bought it 3 years ago. Does this indicate that it might be the WG thats stuck?

[tekstil]

Your best bet is to take wastegate apart to check internal condition. Check if it's stuck, something broken inside or maybe someone at some point took it apart and put it back together wrong.

[Lopez90]

Anyone got link of how things is supposed to look inside?

[tekstil]

Some info here, it's a mix of 10V and 20V:
http://www.sjmautotechnik.com/parts_...ts/wginst.html

Edit: also might be of interest:
http://www.sjmautotechnik.com/troubl.../20vboost.html

[Lopez90]

Thanks! The diaphragm looks fine.
I know the previous owner had 500bhp. Could it be that the spring is changed and stock setup cant control the spring?

Attached pictures of the spring if its possible to see if its stock spring or not?

[newsh]

That's a stock spring which is why it’s opening at about 0.4Bar

If the diaphragm was split the wastegate wouldn’t open and you’d get too much boost

[Lopez90]

Wastegate isnt seized either.

[newsh]

Had to adjust the exhaust so i had a look inside aswell but couldnt find anything blocking it.

swapped DV, and changed front knock sensor. Cant «feel» n75 clicking but i think i can hear the click when i rev it under the bonnet. Still no luck with boost.

I blocked the Line from n75 to WG and got boost obove 0,5!! First time since i bought it 3 years ago. Does this indicate that it might be the WG thats stuck?

We need to find out for sure if the ECU is sending the signal to the N75 to invcrease the boost above spring level. I don't think it is.
The N75 should go tic a tic a tic a tic quite fast, like a vibration, when you WOT at idle. You can connect a voltmeter across the plug and check the voltage while driving, ideally an old analogue voltmeter as it's a pulse waveform and hard to see on a DVM.
Or temporarily pull the N75 out of the MAF hose ( block the hole) and run a length of tube from the long output nipple into the cabin and try driving, when the n75 is activated you should get boost pressure coming out of the tube.

[Lopez90]

https://www.youtube.com/shorts/Fjv9v_mxvaw

https://youtu.be/5x6o8E10Bww

you can hear the n75 click in both videos

[le mans]

Have you checked the N75 is plumbed correctly?

https://forums.quattroworld.com/s4s6/threads/2162.phtml

By the way a stronger wastegate spring will lead to higher boost pressure for the same N75 duty cycle.