Here the files...

Hey there!

I'm still struggling with this issue...

What I did so far:

1. spent some money on new ccv hoses underneath the intake manifold. one of them was broken.

It was the one between the manifold and the one-way valve. So i lost some boost there.
Now the engine has about 0,2 bar (3 psi) more pressure around Pmax. Second effect was, that i "lost" some mass air flow -> delta of about 10g/s.
This makes sense so far, the MAF Sensor is reading now a little less, because the air isn't escaping through this hose.
If I do a leak test up to 2,5 bar (36 psi) there is no fluctuation of air. The air is slowly blowing by the pistons. You can hear it, if you take out the dipstick for the oil. I put on pressure at the first hose after the pressure pipe. So it still could be, that i lose some air between charger and this spot (hose to dv or to n75). I tried to check this both hoses by dismounting them and do a pressure check. They also seem to be ok.


2. bought a new DV and installed it. I heard some strange noise when the charger was boosting. thought the membrane could be torn. the noise is still there sometimes...

One thing with the DV which I don't understand completely: The charge pressure is "controlling" the DV? So for example, if the engine has 1 bar (14 psi) boost pressure, this pressure is "closing" the DV? This 1 bar is on the little pipe on the top of the DV to hold it closed? So what is this N249 for? Maybe there is something broken and the pressure is not closing the DV correctly?
If YES, this could be an explanation for the low mass air flow? It wold be an open circuit from "after charger" to "front of charger".

3. installed a gopro to see if the inlet is collapsing at WOT.

There was no collapsing visible. I ended up buying the SAMCO inlet hose. Still no effect. Same MAF as before.

4. new air filter and removing the inlet before the airbox.

no effect.


Attached i have an actual log. There you can see the still low mass air flow, although the engine should be able to do ~200g/s. The second issue is that the actual boost pressure at high rpm is also really low. This issues are the same with stock software! I'm pretty sure it's still a hardware problem.

Do some of you have some ideas? Maybe the MAF Sensor is broken? The values below 3000 rpm seem to be ok if I compare it to other 1.8t BAM engines. If I buy a new MAF-Sensor it wouldn't solve the problem with the "low" boost at high rpm?

one more thing for information the idle is a bit oscilating...

Thanks in advance.

What turbo do you have?

For the boost, weak actuator? I had issues with mine and had to change it.

Maf readings... I guess try a new maf, they tend to under read when they die don't they?

I checked the actuator by applying negative positive pressure with a syringe... it held it's position for more than five minutes...

The WGDC looks also fine to me if i compare it to similar engines. until rpms > than 3500 rpms... it looks like there is a bottleneck somewhere (for me). (intake or exhaus system)

consequences of this bottleneck is stagnating mass air flow --> and the effect of this is low boost, since the turbine is not getting enough exhaust mass air flow.

I also calculated mass air flow with the AFR values and the injector on time... it also seems to fit that the maf readings are right...

this above is all just thinking! maybe I'm wrong...

That means your turbo is done or your wg is leaking

i will take a look at the wg when I find time...

Today I did a log with ps_w.

msdk is oscillating really weird above 4000 rpm... hardware wasn't touched.