Our turbo needs work, currently no power anymore (internal wastegate? wastegate actuator? DV? NV75 valve (no idea what this is)? other?).

The turbo also makes more of a "shhhhh" noise when you give it gas rather than the normal light whistling sound.

The torque increase that formerly kicked in around 1950 RPM is not there. Stepping off the gas still produces the audible wooosh.

Since I have not dug into the engine at all (consider me a 1.8T newbie), I need help to go about the troubleshooting. I spent some time yesterday trying to get a bit more familiar with the setup.

- when revving up the engine really high, the actuator of the wast gate is moving.
- there is a 'rattling' noise that I was not able to pinpoint when the engine revs down
- It's incredibly tight around the turbo and intake; I need help locating the components and how to check them out.
- Need help learning which is controlling what.
- where should I start and how?
- leaks (vacuum, charged air, exhaust/turbo)?
- component failure (wastegate, turbo, diverter
- control failure (connectors, sensors, tubing,etc.)

Thanks.

 

Step one: Take the little K03 out, clean it up real nice, and stick it on a desk on top of some papers (a.k.a. paperweight)

Step two: Upgrade to an Elim

Step three: enjoy...

Just saying!

 

Sounds like the wastegate is stuck open - the sound you describe could be air blowing through the gate (which is internal). The rattling may be a broken wastegate actuator arm. Member osin34 is dealing with this right now on his car too. Send him a message - he can fill you in more in-depth and can compare notes to see if your problem and his are the same.

 

Update: When revving up the car really high, the waste gate actuator is moving. Does it mean the internal flap is not stuck?

 

my situation is as follows.. hopefully this will help you out? turns out there isnt a problem with my actuator arm, rather the flap on the exhaust side of the turbo.. it is loose and stays open at all times.. it rattles just like you are saying upon deceleration, however i am still making "ok boost" depending on gear and RPMs between 13-17 psi.. somedays its much more consistent and powerful somedays it isnt.. just depends on how the flap is working and sitting at the moment i guess.. it could be that the flap is broken to the point where the actuator arm is no longer opening or closing the flap..

all of this being said, the easiest way of knowing the situation in its entirety, you should disconnect your CAT from the turbo if you can, and get a little mirror and look inside the turbo, and see how things are.. cause when i was putting in my test pipe i took a look and could clearly see that the flap was rattling cause it was very loose and was not staying shut, it was staying open all the time.. but my car still boosts.. it almost sounds like yours is possibly not moving at all? which would mean the flap is broken off from the arm.. but im not sure without you being able to see it? if you can get to the turbo and check it out with a mirror i think youll have a much better insight of whats going on in there.. but even though these are your issues it sounds like a new turbo is what you and i both need..

 

Osin34, thanks for you input. I'll check tomorrow if I can easily take the cat off and see if I can look into the turbo to see the flap.

I don't have a boost gauge, so I don't know if there is no boost, some or all; but power is off. Car runs fine, not gas mileage issues either.

With the mods, the car should fly. I estimate from the 200 hp, there are maybe 120 hp left.

 

yea see from what you mention there, that seems like no power at all.. and my problem was a plugged catalytic converter.. is it possible this is your issue too? cause like youre saying, i am APR tuned, Borla Cat back, Forge DV, K&N intake, and with all those mods i was pushing real good power, and then it just went to ****, and i mean ****.. i have a boost gauge and it was coming back to 0 from vac and wouldnt let me spool.. (i know you already know this, but especially with your mods, make a boost gauge the next on the list) it really just does help so much with monotoring the system in the car, and when something goes wrong you wont just have an inkling from the feel of the car, youll have visual evidence as well.. but def take a look see inside and let us know what you see.. we'll keep an eye on this thread for ya buddy

 

I took the car out yesterday. Power comes on at 4000 rpm (way higher than before!!!).
Also: when revving the car (in neutral), the waste gate actuator moves briefly, but only at very high RPM. I spliced in a tire pressure gauge (don't currently have anything better). At the RPM when actuator moves, the gauge shows some pressure (hard to tell, since 10 psi is only a notch over zero).
==> sometimes, there is some boost.

Today, I took the test pipe out (what a pain). I can reach into the turbo. The waste gate flap is all floppy, wobbling.

I took these pictures:



What should I test/try/feel/check on the wastegate?

 

After removing the test pipe (and noticing how loose the wastegate flap is), I decided to try to get the turbo out (in anticipation that it as to come out to either try a flap fix, or get new turbo in).

I got the 3 top bolts off (had to remove the alu heat shield above to get better access).
I disconnected the big intake hose.
I disconnected the big charged air hose.
I disconnected the 2 (one oil, one water?) lines right on top of the turbo.

Turbo moves, but still seems to be held by a bolt connecting it to a long brace arm (6 mm hex). This one is hard to reach from the bottom, and the only hex 6 I have does not have much leverage.

What else has to come off?


Help, please!

 

I got the turbo out (not sure if I will later get it in this way). Took oil return line off at the oil pan, took the bracket at the block off (impossible to get the screw on the turbo off)/
Twisting and turning got it out somehow (between the air box and the headlight).

The flapper was not anymore pushed closed by the spring of the actuator. Adjusting the set screws on the actuator probably would have been all there is to fix the problem.
Now, after months of driving around with reduced power and a rattling wastegate flapper has ruined the flapper. Not sure if it can be replaced.

See pictures below.