# DPF clogged, cleaning and readings from differential pressure sensor.



## kicku (Apr 8, 2018)

So, it's a old car but this does not mean i don't like my beast.
Everything started with the throttle body mechanism giving random errors, untill one day when died.
So...engine in limp mode and push a 2,5ton beast to 80km/h ...well it's take a while :screwy:
After sorted out the throttle body, discovered with vcds that dpf is clogged.
Great! Now what's next??
So, putting the vcds on it discovered that pression on in / out dpf at 770rpm were almost identical at 7,8mbar. That's no good as i knew...the input pression has to be not over 6mbar and the outside under 4mbar.
...obviusly not my case.



Note the mass carbon at 61,2 (suppose were mg.)

At this point, i was uncertainly if the differential sensor readings are fake or not.
So, take it outside for a ride...(well...half ride  ) with vcds attached to see in real time what happends. And i did got these readings:



At 1400rpm the in pressure raise at 27mbar.

Then at almost 2100rpm raises at almost 43mbar.



After almost drove half hour the temperature were at 300°C at input, with pressure between 30 and 100mbar.









Well, yesterday, found the lift free so i raised the car on it with the "check only" in my mind.
Previously i've seen the nuts on dpf snapped. Only touched with a nipper and they falled down. These nuts must be inox or copper...but someone maybe did not found the time to change them. 

Everything under my car it's rusted...i think the previous owner did not care too much about.



The upper nut was a hell nut...





Taking off in my case was a little difficult because of these nuts. I used a small hammer to separate the dpf from catalyzer.
This was enough to knackering the temperature sensor. I did not beat on it nor touch it in every way, but later, i had error on it "short to plus". 
Maybe because it were almost dead first... If the sensor was not enough...the flexible pipe after the catalyzer did a crack on it... 



So...what's next now?:sly:

After this, i got it off from the exhaust pipe.

This is what i've found at inlet side:



This is the outlet side after washing it.



So, i had washed the dpf ONLY with simply ambient temperature water at low pressure (2bars...not more) for almost half hour. Nothing else.
Simply purge by both sides with water untill the black water will became just clean water coming out.

After this i blew with air ( 6 bar compressor ) and let it stay for almost 30 minutes to get dried.
Then, found 2 studs from an old exhaust collector with nuts, put them in the place of the old ones and after take down the car...start the engine with vcds to see what happends.

Well...at first the dpf error clogged filter came together with the temperature sensor. 



Then i've delete them, and the clogged dpf error did not came out anymore. 

Already here i did seen the difference. The pressure sensor readings were more realistic. The mass carbon more lower. All this after only 7-10 minutes running at idle speed.



After almost 15 minutes i've got these readings:



The mass carbon and differential pressure became lower and lower.



After a half hour...




Next i have to change the temperature sensor, otherwise the regenerate cycle will not start. These days i will do it.


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## snapdragon (Aug 8, 2006)

Brilliant detailed post and photos...thank you.
Amazing the filter still works after this time abeit after a clean.


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## kicku (Apr 8, 2018)

Thank you.
Yes, hope will last for a while


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## kicku (Apr 8, 2018)

Today i changed the temperature sensor. It was a hell stud...almost broken the 17mm key on it.
Now i have these values at cold engine:



Tomorrow i will start a forced dpf regeneration.


Forgot to mention: the "new" sensor at room temperature +25°C gave me almost 215 ohm resistance (0,22kohm). Warming it with a lighter arrived to almost 300 ohm (0,3kohm).


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## kicku (Apr 8, 2018)

*Successful regeneration? Hope so...*

Took less than 10 minutes to finish, after run the "10016" code on coding II as ross-tech site say, the engine raise the rpm ( by itself ) to 1500rpm. When temperature on inlet dpf arrived to almost 800°C, the rpm was lowered to 1000rpm for almost 3 minutes, then dropped to idle 750rpm.

This after 2-3 min.



1 min later



Almost 5 min from the start



10 min later, when rpm were dropped to idle.



And this is the temperature sensor...better say what remains of it...have no idea why the thread were bricked already because of overheat or doh...



Hope this topic will help those trying to fix dpf issue, around all internet didn't find anything with detailed info.
...maybe i didn't searched in the right place


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## robbie-rocket-pants (Mar 25, 2012)

Very interesting write up & photos. Thank you kicku. :thumbup:


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## bolosicubolo (Oct 14, 2018)

Hi guys,
I have a 3.0 Phaeton from 2010 and I did some DPF readings with cold engine after startup:








I find strange that the offset diff pressure and ash are reading 0.
I looked for this values because I have a small vibration for some time after I start the car, vibration that starts to disappear after 15-20 min, well beyond after engine gets to 90 Celsius. Can you comment on this readings? I also checked the injector offsets and the highest was around 0.8. And is not the from the engine mounts either.
Thanks.


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## kicku (Apr 8, 2018)

bolosicubolo said:


> Hi guys,
> I have a 3.0 Phaeton from 2010 and I did some DPF readings with cold engine after startup:
> 
> 
> ...


My guess the dpf has nothing to do with your issue.
Better idea would be to check the egr if it's clean and fully working as should.


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