Swoosh sound, no boost

[wmertler]

2003 Audi A4 Quattro 1.8t

Drove home from work today, planning on changing the MAF, it had been replaced at 145k with a cheap ebay MAF which was just as bad as the OEM one that failed. So I had ordered an OEM Bosch one, so when I got home installed it. Hoping it was the reason to my low boost conditions. Installed it with battery unhooked, hooked it back up turned on accessories reset ecu with scanner. Turned on car idled good, so I decided to test it out and go for a drive got about 30 seconds in and could tell "didnt punch it yet" boost was being made could here the faint whistle more predominant then before. Then got about half throttle and it got loud, like the turbo was free spinning. Like it was a hose popped off.

Here's what I've checked

-Visually checked boost hoses all are tight?
-Boost leak test No leaks? Wont hold pressure for more then 5 seconds but if I pressure to 15 psi bleeds off in about 5-8 seconds "guess" Hear bubbling coming from valve cover from oil "cap was off" per leak specs


Should mention

Within last 3k miles heres the maintenance I've done


Timing Belt / Tensioner
Head Gasket, Bolts
Intake Gasket
TB Gasket
Water Pump
Brand new Borg Warner K03 turbo
all new gaskets used
Valve cover gaskets
Rear Coolant Flange
All new silicone boost hoses
newer air filter
just changed oil, mobile 1 filter with liqui moly 5w-40
just changed Trans Fluid Filter/ Oil w/ Febi
Fresh coolant with rebuild.
Motor mounts with RS4 style from ecstuning
new rear window regulators both sides
new window switch on drivers door
new snub mount ecs poly

Probably more i forgot , has 150k miles. Pretty much getting it ready for another 100k but keep getting more issues lol. Owned this since 133k and have babied it oil changes every 3k with synthetic and premium filters

Mods

Test pipe
No tune unless it has been by previous owner, never seen it boost over 10/11 psi at max 5th gear on a hill.

Exhaust has a pretty good leak at the entrance to the resonator "waiting to replace" don't think this is relevant.

Sorry for the long post



Throw me any ideas



EDIT

Also put on new air pump plastics hoses 'broke during rebuild' from air box and to air box one.

EDIT #2

Forgot about also changed diverter valve to a brand new audi tt 1.8t valve

And have a new n75 valve coming OEM

[Furly]

You check your wastegate ? Is it a legit BW turbo or a replica?

[wmertler]

Legit BW with proper BW tag and SN on it. Wasnt going to do a ebay turbo lol


Just remembered , I also deleted the air resonator that connects to diverter valve area. Has 1' pipe inline which I believe is a common weight reduction boost response mod


EDIT: Dumb/Tired

[Furly]

A wastegate and diverter valve are two totally different things.
Your wastegate is attached to the turbo and has a flap on the hot side with a rod controlling it open and close.

[wmertler]

hurp, sorry knew that . Was tired when I wrote that yeah I'll check it after work. Would have been too warn to check last night anyways.

[Luxus Panzer]

I also deleted the air resonator that connects to diverter valve area. Has 1' pipe inline which I believe is a common weight reduction boost response mod


EDIT: Dumb/Tired

I thought this was only done when installing a FMIC? Do you not need this resonator with the stock SMIC??

[5ktq]

I think it's just to make the intake tract less noisy, some voodoo

[Steve Bassen]

Check your suction jet pump?

[wmertler]

Check your suction jet pump?

I can check that, but that wouldn't be rpm dependent would it?

[old guy]

"Then got about half throttle and it got loud, like the turbo was free spinning. Like it was a hose popped off."

You need to perform a boost leak test. Your description pretty much indicates a boost pressure leak somewhere.

[Steve Bassen]

I can check that, but that wouldn't be rpm dependent would it?

Once the end of the jet pump pops off, it'll never build boost at any rpm.

[wmertler]

Alright I'll tear into it tomorrow and check everything out. Drove the S4 today so I didn't hurt the turbo just in case.

[wmertler]

"Then got about half throttle and it got loud, like the turbo was free spinning. Like it was a hose popped off."

You need to perform a boost leak test. Your description pretty much indicates a boost pressure leak somewhere.

Yeah I boost leak tested and didnt hear any leaks, besides air going by rings through oil.


I plugged the 2 lines that I thought was it, cant find a good video showing the correct way to do it on the b6 platform. which surprises me. Every time I find a forum post about it the pictures are missing because of age.
The way I've been doing it was plugging the 1 inch line going to the crank breather and the other line coming of the cold side of the turbo thats about 3/8. Pressure to 15 psi and it leaks down in about 5 seconds. Only leak I hear is through the crankcase from air making it by the pistons.

EDIT
Technically plugged 3 lines 3rd had a pressure gauge in it.

[wmertler]

Here's a video from the boost leak test I preformed today are these typical results? Only leak I hear is from the oil fill cap.
https://youtu.be/_5Cz098rqzU

Also checked the plastic air lines coming off of Air pump all seem tight.

Also jet pump is in perfect shape forgot to mention that was replaced when the rebuild was done with a Uro parts one. double check it , its still in 1 peice no leak there.

[wmertler]

The whine is definately coming from the turbo/ air pump area but cant be sure which.