DPF wash out and rebuild

[The_Hawk]

Sounds interesting Steve. On one hand I like the much simpler approach, on the other I wonder how it can work as well as striping the whole thing down and cleaning it out.

A quick google turns up this PDF:

http://www.liqui-moly.com/liquimoly/...ger_EN.pdf.pdf

If it does indeed work you have to wonder why VW don't have an equivalent cleaning technique rather than a full (and expensive) replacement... being good environmental citizens and all...

[volksMuller]

To answer the question ....our tool has probes that are correctly angled to fit through the pressure sensor holes....this allows easy access and easy clean......yes we can disconnect the DPF and wash in situ also.....hope to have a video up to show how its done with the values before and after.....cheers steve

[gldgti]

Nomatter what cleaning agent you use, you can't get rid of the ash without a back-flush and I think thats Gregs main point in this thread. Interesting to see this method adopted right across industry however, as opposed to regular replacement - it certainly seems like the aftermarket is supporting commercial users in creating these semi-regular maintenance schemes where back-flushing is done rather than dpf replacement.

[Greg Roles]

greg , we achieve the same ash load content measured on VAS after using the luiqi moly clean programme....we perform this task for many dealers who follow vw's protocol and say it requires replacement......many a tdi in limp mode with high% blocked filters can be saved .....some whilst in car others need to be removed and cleaned...we charge $395.00 for the task and have hit a home run on EVERY job.....lot less work with the exact same result......just saying there are others way's that work just as well..cheers steve

Good to know someone is offering this as a service, and if you can get similar "new" ash load values then I'd say to everyone to go for this option. I just like doing things 110%.

High flow DPF is still on the cards, but quite a huge task. Catch can kits, and the loooooong overdue Provent kits FAR closer, with me currently pricing medium sized CAD mills.

[Greg Roles]

Nomatter what cleaning agent you use, you can't get rid of the ash without a back-flush and I think thats Gregs main point in this thread. Interesting to see this method adopted right across industry however, as opposed to regular replacement - it certainly seems like the aftermarket is supporting commercial users in creating these semi-regular maintenance schemes where back-flushing is done rather than dpf replacement.

Truck industry would be driving this need mate, given the miles those guys drive.

[gldgti]

Catch can kits, and the loooooong overdue Provent kits FAR closer, with me currently pricing medium sized CAD mills.

Before you commit to that mate, you might want to talk to some lasercutters. My company has a good relationship with another company (they are a big supplier of parts to us) that do lasercutting and CNC folding - which is cheaper and more efficient than milling, and the quality is excellent. (More than accurate and good looking enough for bracketry and flanges).

Lots of lasercut/cnc folding companies around - its a rapidly growing industry that is replacing a lot of expensive machining jobs.

[Greg Roles]

I figured you'd be the last person in the world to try and talk me out of my own mill!!

Billet TDI block anyone ??

[gldgti]

I figured you'd be the last person in the world to try and talk me out of my own mill!!

Billet TDI block anyone ??

Dont get me wrong - having your own mill would be fantastic I reckon!

Theres some great vids on youtube of blocks being milled from billet... one of a W16 engine comes to mind.

But seriously, todays laser is so good and coupled with the CNC folding, bracketry and flanges for exhaust/intake parts are just so cheap and easy. All you need is a CAD program and you can get just about anything made easily.

[Greg Roles]

Hi Greg, just wanted to pick your brain in regards to the DPF wash out thread you posted.
I have a feeling my DPF is on its way out - only got 70,000kms on it but its been tuned from pretty much new. The car goes into Regen pretty much every 3 days now ( just the raised revs, not the light on dash thing ) and the last time I had the light come on I had to do a 20 - 25 minute run along the highway to clear it, its never taken that long before.
Is this along the lines of what you meant when you said you had regens every 50kms or did you have the dash light come on. You mention 30g carbon going to 40g carbon which I have no idea what you mean.

Anyway, with regards to the wash out, you need to blast the water into the opposite flow of the exhaust?
What do you mean by having to wire it together to pull the can back together?
What do you mean by resetting the ash level down to 5grams to be safe? I assume this is somekind of ECU reading ? Is this something that has to be done or can I just cut up my DPF, wash it out, reweld and install again? Will the ECU automatically determine the carbon level?

Finally, how far can I go with the car before its too late and I cant do this flush - I don't want the dash light to go on, unable to clear it and then the car go into limp mode right?
Ie should I do this soon? I'm certainly not paying for a new DPF and not 100% convinced that the DPF delete option is the best choice.


Got this PM, and to save getting this type of question PM several times thought it best to take it public.

The symptoms above are typical of a DPF reaching the end of it's life, in that it is approaching "full". For those with Vag Com, "full" is towards 40 grams on channel 68 under control module/engine/ measuring blocks. The symptoms lone tell you the DPF has little capacity left, as it is regenning very frequently. I intend to write a big article on DPF's as they confuse a lot of people, including those who should know better!

Anyway you need to cut your DPF open, and reverse flush it to blow all the white ash back out of it. Instead of cutting it right out like I did, I would suggest cutting outside the top and bottom canister welds, as you can leave the core wrapped in the steel can. There is a support shelf at each weld to keep the SiC core in place, so cut above and below the welds by a cm or so to just remove the ends.

Go to town with a pressure washer and wash against exhaust flow. You can put a washer nozzle right up to the core and not damage it, but be very careful handling it, as it is very pottery like and can easily crack and shatter like a clay pot. It took me a good hour to get every last bit of fine white ash out, but even getting most of it out will get you a stack of new lifespan.

The car knows how much ash or load is in the core, and can correct for a washed out DPF, but it still makes sense to monitor the corrected ash load on channel 068 as outlined above, and adjust this under advanced coding off the top of my head. I will address all the Vag Com settings in a proper article.

My own DPF has 30k on it since washing it out, and it is still performing as per new. Soot load has gone up about 2 grams from the five I roughly started with. All seems perfect to me.

If you don't do this promptly as your DPF starts regenning all the time, it will indeed reach its end, the car will register the pressure difference as the end of lifespan, and the car will be in permanent limp. It all comes down to what the two pressure sensors "see" and it's hard to trick them.

I will get onto my full DPF write up in the next week or so, as the above poster wont be alone!

[AlexRO]

Off topic but related question ..

Ive got the viezu tune on my car, would I be able to get a downpipe fitted, deleting DPF, and have viezu tune that in and code it so i dont get a CEL ? The only issue that i can think of would be the power increase Id be getting from removing the restriction, and by what viezu have told me, im pretty much running very close to the torque the DSG can handle.. (400ish?)

I just clicked over 100k so I might have to think about things like this in the future