This is exactly the kind of reply I like to see.
The problem of low power during regen remains.
Good:
The exhaust brake is more or less set correctly.
The injectors are good. Low rpm delta, good injection quantity.
The intake throttle valve has been modified.
Bad: The loose pipe between the MAF sensor and turbo. It's been sucking in dirt, hasn't it?
Soot in tailpipe.
Unusual: DPR inlet temp higher than outlet.
So, we're looking at an airflow problem. Usually this is caused by the ITV sticking shut, but the modifications pretty much cure that.
There are several things to do.
I would want to know the intake air pressure during an auto regen. I live near sea level and I generally see between 30-35 psi absolute (atmospheric pressure plus boost pressure).
If that is low (and I suspect it is), I'd remove the turbo intake piping and check the shaft for radial and axial endplay. I'd also check the compressor wheel for FOD.
Check the intake air pressure sensor sensor pipe and tube for blockage.
Clean the mass airflow sensor.
Remove the dpf and inspect the inlet and outlet for damage. You'll know it when you see it.
We finally got back to this 2008 338 with lack of power issue.
Took dpr a part. The filter has some weird damage on outlet side. It's like a thin crack alone its outline. And also you can see some small melted particles
I don't have a good closeup picture, but here's some:
We replaced it with the used one from another truck, that is waiting for major repair.
problem still exists - a bit low power, and very low during regen
We cleaned air pressure sensor, turbo seems to be ok, have sprayed thst nickel antiseeze in it
Not sure which "compressor wheel" you mentioned that is related to turbo. Is that a main air compressor that's attached to a flywheel?
also, wondering how ecu(or bcu) is monitoring regen process. Does it go buy inlet and outlet temp only? flow resistance? what happens if one will drill a hole through the filter?
I could only monitor intake air flow (our dx will not connect to Bcu to track boost pressure(if I am not mistaken its found in bcu)
so it is around 90 (86-109) while driving on auto regen
And around 180 (170-200) when its off
Also, p0400 active code appeared again. It was active and disappeared possibly after egr was taken off and cleaned.
we are going to replace egr valve solenoid tomorrow and see what happens.