DPF - To remove or not?

bear1

I know this topic has come up before but I wanted to get some advice.
My Passat 2.0 diesel has a DPF which about once a month regens itself.
Car is used for long journeys quite often so no issues there.
Today however the DPF warning light has come on and asking to consult the manual which states that the DPF is blocked and will need to be cleaned.
I'll take it for a blast later on to see if it cures it but it also got me wondering if I should just do away with it altogether?
What are the pros and cons?

shietpilot

What about buying a scan tool for around 40 euro and doing a forced regeneration once a month?

bear1

That's a possibility but I would have been under the impression that it would need to be an advanced type of scanner to do that sort of job? Is it also beneficial? I.e would it not do more harm than good forcing it all the time?

Gumbo

Pros : Remap and release more power.

Cons : NCT fail as they now look for the outer shell of the DPF seemly. You can leave the shell and gut the internals though.

shietpilot

bear1 wrote: »

That's a possibility but I would have been under the impression that it would need to be an advanced type of scanner to do that sort of job? Is it also beneficial? I.e would it not do more harm than good forcing it all the time?

You can pick up a DS150 from China for €40 and it's an advanced bit of kit. DPF regeneration is possible on most if not all models with DPFs fitted.

I don't think forced regeneration could cause more damage. At the end of the day the DPF gets blocked up because of a lack of regeneration. The only downside is you'd use a bit of fuel. Sure you could even do it every 2 months if you're worried.

grogi

shietpilot wrote: »

You can pick up a DS150 from China for €40 and it's an advanced bit of kit. DPF regeneration is possible on most if not all models with DPFs fitted.

I don't think forced regeneration could cause more damage. At the end of the day the DPF gets blocked up because of a lack of regeneration. The only downside is you'd use a bit of fuel. Sure you could even do it every 2 months if you're worried.

It is a good practice to change the oil after a forced regeneration.

shietpilot

grogi wrote: »

It is a good practice to change the oil after a forced regeneration.

Interesting to know.

I just checked the software there and it's possible to do a DPF generation on a Passat and also check the % carbon content in the DPF. I don't know how you schedule your oil changes or what mileage you do but it seems like an option and maybe even cheaper than gutting the DPF

Avatar MIA

Hi OP,

You might want to read this thread...

http://www.boards.ie/vbulletin/showthread.php?t=2057549319

Although, I've a follow up thread to post now that may or may not be related...

GustavoFring

Is the Passat a CR engine? Don't automatically assume it's the dpf - a lot of the time the issue is one of the two pressure sensors. Any limp mode?

bear1

GustavoFring wrote: »

Is the Passat a CR engine? Don't automatically assume it's the dpf - a lot of the time the issue is one of the two pressure sensors. Any limp mode?

No it's the PD engine. 2007 170 version.

bear1

kceire wrote: »

Pros : Remap and release more power.

Cons : NCT fail as they now look for the outer shell of the DPF seemly. You can leave the shell and gut the internals though.

I don't need to worry about that, I'm using the car in Poland so different annual check rules
Taking a look around I'm getting quotes of about 250e for a total delete.
Regarding oil changes, I'm having the car serviced in a week as it will be off to Italy for 10 days.

bear1

My other concern is the ****e I would release into the atmosphere if I do have the DPF removed - but I'm reading conflicting arguments as to whether it is better for the environment to have the DPF removed or to have it installed.

grogi

shietpilot wrote: »

Interesting to know.

I just checked the software there and it's possible to do a DPF generation on a Passat and also check the % carbon content in the DPF. I don't know how you schedule your oil changes or what mileage you do but it seems like an option and maybe even cheaper than gutting the DPF

The ECU does two things:
- measures the pressure difference at the entry and exit from DPF. That gives the measured carbon % in DPF.
- estimates the carbon build-up by monitoring the working conditions of the engine - this gives the estimated carbon % in DPF.

If any of those two reach the defined threshold, active regeneration will be initialised. ECU will add additional fuel injection late in the cycle, so that loads of it get into the DPF increasing the temperature, allowing the soot to oxidise. However, some of the diesel gets to the engine oil diluting it a bit (and much more on SkyActive diesels).

That's why after a forced regen - which uses A LOT of fuel - you should change the oil.

Active regeneration is not the only way to get rid of the carbon from DPF. If the temperature of the filter reaches IIRC ~500*C, passive regeneration happens. It does not need to be initialised or anything - happens when conditions are there. And one will get there by driving aggressively, high speed/low gears etc.

DFP gets blocked by ash build-up as well - this happens by using dodgy fuel or incorrect oil. Ash build-up cannot be cleaned by the car on its own, physical cleaning is required. I've heart numerous reports of pressure washer doing miracles.

grogi

bear1 wrote: »

My other concern is the ****e I would release into the atmosphere if I do have the DPF removed - but I'm reading conflicting arguments as to whether it is better for the environment to have the DPF removed or to have it installed.

No, under no circumstances it is not better to drive without DPF.

What DPF is doing is capturing soot - non-burned carbon particles. When the conditions are there (either during passive or active regeneration) those carbon molecules oxidise and get out as harmless CO2. Overall increase in CO2 emission is negligible, if that's what you're concerned about. During active regeneration there will be an increase in (harmful stuff) NOx emissions - but integrated over the cycle between regens those will be negligible as well.

Soot particles (PM) are veeery harmful (http://www.euro.who.int/__data/assets/pdf_file/0006/189051/Health-effects-of-particulate-matter-final-Eng.pdf). DPF allows to reduce them at least by 85%, with newer applications reaching efficiency of 100%.

I don't need to worry about that, I'm using the car in Poland so different annual check rules

Authorities, especially around Cracow and other highly-smogged areas, started to perform on-the-spot checks as well... Be aware..

Avatar MIA

bear1 wrote: »

I know this topic has come up before but I wanted to get some advice.
My Passat 2.0 diesel has a DPF which about once a month regens itself.
Car is used for long journeys quite often so no issues there.
Today however the DPF warning light has come on and asking to consult the manual which states that the DPF is blocked and will need to be cleaned.
I'll take it for a blast later on to see if it cures it but it also got me wondering if I should just do away with it altogether?
What are the pros and cons?

Just noticed you don't seem to have problems with performance, so all you need to do is drive it for a distance to ensure the regen happens.

As long as you've decent milage to do I'd keep the DPF.

My problem was that my car usage went from motorway to very seldom city driving - which the DPF doesn't like.

bear1

grogi wrote: »

No, under no circumstances it is not better to drive without DPF.

What DPF is doing is capturing soot - non-burned carbon particles. When the conditions are there (either during passive or active regeneration) those carbon molecules oxidise and get out as harmless CO2. Overall increase in CO2 emission is negligible, if that's what you're concerned about. During active regeneration there will be an increase in (harmful stuff) NOx emissions - but integrated over the cycle between regens those will be negligible as well.

Soot particles (PM) are veeery harmful (http://www.euro.who.int/__data/assets/pdf_file/0006/189051/Health-effects-of-particulate-matter-final-Eng.pdf). DPF allows to reduce them at least by 85%, with newer applications reaching efficiency of 100%.



Authorities, especially around Cracow and other highly-smogged areas, started to perform on-the-spot checks as well... Be aware..

Thanks Grogi, car is mainly used around the Warsaw area.
Good to know though, I'll keep it I think and just take it for more rigorous drives even though it goes on long enough journeys cause of work.

bear1

Just an update to this.
Car ended up going into limp home mode the other day and acting generally strange.
Brought it to the mechanic today who will take a look, give it a full service and see how it goes.
Waiting for the call to tell me what the ECU is saying

Avatar MIA

bear1 wrote: »

Just an update to this.
Car ended up going into limp home mode the other day and acting generally strange.
Brought it to the mechanic today who will take a look, give it a full service and see how it goes.
Waiting for the call to tell me what the ECU is saying

Feck, almost exactly what happened to me.

For me the DPF light came on, and I drove it until it went off, couple of weeks later it came back on, then went into limp mode. End result - gone too far to go through regen mode as too great a risk to set the car on fire. I was quoted approx. €3k to get in replaced.

In the end... well, read the thread

mikeecho

The motor tax system is encouraging people to buy cars that don't suit their needs.

I currently have a diesel, but mrs echo is looking at something newer, but everything seems to be diesel.
She only does 14miles per day in total.
A petrol is what's needed, but try finding a 2L petrol 3/5series, or A4/6.

They don't exist in any significant numbers.

I clearly believe that motor tax should be a fixed rate for all ice cars.
Wheter it be 995cc or 6000cc

grogi

mikeecho wrote: »

I clearly believe that motor tax should be a fixed rate for all ice cars.
Wheter it be 995cc or 6000cc

It should depend on the weight of the car....

mikeecho

grogi wrote: »

It should depend on the weight of the car....

Nope

Flat rate for everyone

Special Circumstances

I second the fat car tax. :-)

Del2005

grogi wrote: »

It should depend on the weight of the car....

A 2t car doing 14km per day is doing a lot less damage than a 1t car doing 300km per day.

dr.fuzzenstein

shietpilot wrote: »

What about buying a scan tool for around 40 euro and doing a forced regeneration once a month?

grogi wrote: »

It is a good practice to change the oil after a forced regeneration.

Monthly oilchanges?! Am I the only one who finds this in any way remarkable?
Mine gets changed every 20k km, which does take a few months to do, changing the oil every month is madness.

markpb

dr.fuzzenstein wrote:

Monthly oilchanges?! Am I the only one who finds this in any way remarkable?

Forced regeneration is done statically through the ODB connection. If you're doing that monthly, something has gone terribly wrong with your DPF.

dr.fuzzenstein

markpb wrote: »

Forced regeneration is done statically through the ODB connection. If you're doing that monthly, something has gone terribly wrong with your DPF.

I know, that's why I'm amazed it gets recommended as a routing option along with oilchanges. Yeah, just force regen and change the oil every 4 weeks, be grand, no problem, all normal. :eek:

grogi

Del2005 wrote: »

A 2t car doing 14km per day is doing a lot less damage than a 1t car doing 300km per day.

It keeps going for free, right?

I advocate for getting rid of MotorTax all together and taxing the petrol more - it is precisely known how much CO2 burning a litre of petrol or diesel produces. However, if we need to have a fixed yearly tax, basing it on the weight of the vehicle is much better idea than unrealistic CO2 figures.

But this is far off-topic...

Special Circumstances

markpb wrote: »

Forced regeneration is done statically through the ODB connection. If you're doing that monthly, something has gone terribly wrong with your DPF.

Yeah, just gut the thing if you get anywhere near that situation. Failed technology.

bear1

Can this thread not descend into a motor tax thread...
I won't be changing the oil every month that is for sure, but I'll change it every 10k km to give the engine as much freshness possible flowing through it's veins.
Still waiting for the call...

RichyX

It's nonsense like this that makes me hate diesel cars.

bear1

Well it turns out it wasn't the DPF.
It would appear my turbo is nearing the end of it's life after 202k km.
Fault code P0299 from VCDS showed up which is that the turbo is underboost

Harcrid

Might not be as bad as you think. I had similar code if not exactly the same one on my 170 Passat CC (CR engine) and it was the turbo actuator that had gone. Much cheaper fix if it is and it's easily checked.

Symptoms were loss of power when engine light came on but never had any excessive smoke at any stage. Just no turbo.

bear1

Harcrid wrote: »

Might not be as bad as you think. I had similar code if not exactly the same one on my 170 Passat CC (CR engine) and it was the turbo actuator that had gone. Much cheaper fix if it is and it's easily checked.

Symptoms were loss of power when engine light came on but never had any excessive smoke at any stage. Just no turbo.

Mine is the pd engine
Just spent quite a bit on it's 200k service.
Drove her hard today on the way back to try and get the symptoms back but it drove more or less ok but its lacking just that bit of ooomph it had a week ago.
Isn't the method to check if the actuator is moving is to see if it moves in and out when the car is switched on and off?

Harcrid

It's activated by vacuum and when the vacuum is applied it should hold it position. On mine the rubber diaphragm had split so it would not hold.

It was my mechanic who had to verify it for me as It was beyond my knowledge but it was easy to test he said. May not be the same issue for you but seems similar.

bear1

I'll dig deeper and see what else I can find.

JBokeh

I had a tiny split in the intercooler pipework on my passat, caused me a right headache with the amount of fault codes it brought up relating to charge sensors and emissions.

I've my DPF was removed already, and it caused huge plumes of smoke due to a a bad air to fuel ratio, and made a whistling noise under load so it was more a case of old skool fault finding by checking the symptoms and working by deduction rather than believing the code reader and just throwing parts at it.

Avatar MIA

JBokeh wrote: »

I had a tiny split in the intercooler pipework on my passat, caused me a right headache with the amount of fault codes it brought up relating to charge sensors and emissions.

I've my DPF was removed already, and it caused huge plumes of smoke due to a a bad air to fuel ratio, and made a whistling noise under load so it was more a case of old skool fault finding by checking the symptoms and working by deduction rather than believing the code reader and just throwing parts at it.

Exactly what I'm experiencing. Finally getting fixed tomorrow.

shietpilot

I would check the vacuum line running to the turbo actuator. On some TDIs the vacuum hose is at a right angle onto the turbo actuator and it can split there from stress and leak.

bear1

shietpilot wrote: »

I would check the vacuum line running to the turbo actuator. On some TDIs the vacuum hose is at a right angle onto the turbo actuator and it can split there from stress and leak.

I'll give them all a shot.
First step is I'll see if the actuator actually moves in and out so I can rule that out.
Then I'll take a look at the hoses for any signs of wear but I'd have thought that I'd have a constant EML light as surely boost leak would constantly trigger a fault no?

shietpilot

bear1 wrote: »

I'll give them all a shot.
First step is I'll see if the actuator actually moves in and out so I can rule that out.
Then I'll take a look at the hoses for any signs of wear but I'd have thought that I'd have a constant EML light as surely boost leak would constantly trigger a fault no?

Intermittent EML sounds like the actuator is getting stuck to be honest. Grab it with your hand and stroke it back and forth 100 times. I used this method on a Toyota which was overboosting every couple of days and would go into limp mode. After doing that it never did it again. When I started moving the actuator it felt very stiff and like it was catching on something but it became much smoother.

We're still talking about turbo actuators of course :D:D

bear1

shietpilot wrote: »

Intermittent EML sounds like the actuator is getting stuck to be honest. Grab it with your hand and stroke it back and forth 100 times. I used this method on a Toyota which was overboosting every couple of days and would go into limp mode. After doing that it never did it again. When I started moving the actuator it felt very stiff and like it was catching on something but it became much smoother.

We're still talking about turbo actuators of course :D:D

Basically I'm going to toss off my actuator :pac:
I'll give that a go too, suppose it makes 0 difference if it is underboosting.

dr.fuzzenstein

bear1 wrote: »

Basically I'm going to toss off my actuator :pac:
I'll give that a go too, suppose it makes 0 difference if it is underboosting.

bear1

Re-update:

So I brought it to a turbo specialist who said that the turbo seems brand new and did a few checks to see if it is holding a vacuum which it seems to be.
They then disconnected a few hoses and rev'd the engine and came back with the diagnostics that the geometry of the turbo hasn't been calibrated properly.
Seem plausible?

Avatar MIA

bear1 wrote: »

came back with the diagnostics that the geometry of the turbo hasn't been calibrated properly.
Seem plausible?

For how long, since manufacture?!?

bear1

Avatar MIA wrote: »

For how long, since manufacture?!?

I've called the dealer that sold the car and they advised that a few weeks before I bought it the turbo was replaced with a new unit by the previous owner.
The previous unfortunately didn't provide documents to back this up so I'm working on the idea that whoever replaced the turbo simply stuck it in and away you go.
So give or take 5/6 months of the turbo running around with the proper geometric measurements.

shietpilot

Better than a forked turbo anyway!

bear1

shietpilot wrote: »

Better than a forked turbo anyway!

True, and I'm glad the turbo is new but calibrating a turbo? I cant understand how this didn't cause a fault the moment it was put in.
Car is with the turbo men now anyway till Monday but I'm somewhat sceptical this is the issue although to be fair they seemed to know what they were doing.
Also, how would you know the calibration is off by removing pipes and testing the vacuum?

shietpilot

bear1 wrote: »

True, and I'm glad the turbo is new but calibrating a turbo? I cant understand how this didn't cause a fault the moment it was put in.
Car is with the turbo men now anyway till Monday but I'm somewhat sceptical this is the issue although to be fair they seemed to know what they were doing.
Also, how would you know the calibration is off by removing pipes and testing the vacuum?

The VNT actuator arm is adjustable with a nut on it. I guess they put in a rebuilt turbo and it wasn't adjusted correctly?

Special Circumstances

bear1 wrote: »

True, and I'm glad the turbo is new but calibrating a turbo? I cant understand how this didn't cause a fault the moment it was put in.
Car is with the turbo men now anyway till Monday but I'm somewhat sceptical this is the issue although to be fair they seemed to know what they were doing.
Also, how would you know the calibration is off by removing pipes and testing the vacuum?

Complete guesswork by me... but you'd think there would be closed loop control (little bit more,little bit less, little bit more laaaaavely!) of the turbo, not just some "day 1 calibration" and open loop (there or thereabouts shur close as you feel like yourself) .

That is, it would self calibrate/regulate via the boost controller. Maybe it does tune itself to a certain extent but it needs outside help to get in the right ballpark first day. But as you say.. you think of it was that far out it would throw a code.

bear1

So I got the car back. Something doesn't feel right, in fact it hasn't felt right since the dpf light came on.
The guy said the turbo is perfectly fine and he has cleaned everything and reset the pressure settings.
But it just feels meh, not a 170bhp engine.
The other thing is that the eng temp grew to 95 degrees when it has always stayed at 90. Now it is 33 degrees here and I was giving it the beans but it never over 90. Checked the coolant levels and all good with no leaks.
I can see my luck is running out.

bear1

Annnd limp home mode.
Gonna have to dig into my savings now.
Suspect the turbo system isn't holding the pressure properly