35d dpf issues
 

Ive been having on and off issues and finally got to replacing the tstat (looking at it it was the original one) now my dpf is essentially plugged, im going to try the liquid molly dpf cleaner and was wondering if anyone has tried it and any tips how to do so. Also i saw on a e90 post a guy punctures a certain vacuum hose which tricks the dpf into constantly doing a regain cycle once at operating temp which would be ideal in my situation.
Any help always appreciated

If the DPF is sooted to the point that a regen is blocked there are faults stored.
Is this the case? What BMW codes?
It is possible to still carefully complete a regen by other means than fooling the differential pressure signal to the DDE.
However, the DPF temps must be carefully watched while it is underway as it is possible to overheat and destroy the monolith.

I dont have the particular bmw codes but rather the generic codes which i can send if helpfull

From what i recall they put a hose with a tiny hole in it to make the dpf look not as clogged to the sensor.
Then they set Rheingold ista or carly to do a dpf regen and then went for a long drive to clean it.
As said be careful of the temperatures, watch it with torque, ista, or Carly.... I'd think keep it below 650 C.

It's a shame these bmw complain about everything but don't bother to monitor a thermostat which really is bad!

Is there magic number not to exceed?

I understand that but which hose in particular, im guessing its the differential dpf sensor and i would do this to the post dpf sensor vaccum line, the immediate generic codes are p244d, p323f, p045e, p2032, p0401

I would think you want to do it on the pre dpf line, bleeds the excess pressure, making the differential lower. I think the issue is when the differential pressure is too high, the dde refuses to run anything.

Magic number if you exceed 650C? 700C? I think would be safe maximums on pre dpf and pre doc. Pre doc is pretty much the temperature that is coming out of the engine exhaust header and through the turbo.
If it goes higher you can lift off coast, or put it in N to lower egt's. I wonder if the regen would even work with you idling, since its so clogged? No clue, I dont recall if what I read explained much about that

Makes sense, i think they describe it as once it gets to operating temp the regen stays engaged so maybe even while idling which is why the temp can spike higher than normal, any idea how to measure the vaccum on the hose?

It's not vacuum, It goes by pressure.
It's a single sensor with 2 lines. Let's say pre dpf is 3 psi and the post dpf is 1psi. The sensor would report 2psi differential pressure.
I read that thread a while back so I don't remember details.

In ista/Rheingold, there's a dpf service that gives you tests to run to check the dpf at idle, 2k, and higher rpm.
They have good values in mbar, like 80 mbar at idle and higher at 2k etc.
1000mbar is 1bar or 14.5 psi. 100mbar is 1.45 psi.
Try a small hole in the pre dpf hose to get it where you're close to what the test wants.
A clogged dpf would have high pressure pre dpf making a high differential.


Once you get that ok with your added hole, hopefully the dde will be ok thinking the dpf is not clogged.
set Rheingold to request a regen.
Drive gently, watching egt pre dpf... Probably best to do it at a time when traffic is low.
If all goes well after a while the regen will finish. Try another regen request, do it again.

After that maybe let engine cool to be able to safely remove the hose with the hole and see if the issue still happens. If not, maybe do another regen and a normal drive.

Here is a link to the original approach that I believe you are discussing:

Diesel Particulate Filter (DTF) - Bimmerfest - BMW Forums

See post number 9 for a discussion and picture of how lpcapital forced the regeneration.

Hope that's helpful. Good luck.