2 hours ago, Orman said:

Do you remember the name of the additive/cleaner used?

The two items in the middle

J02230 & J02250 were used.

39 minutes ago, varooom said:

The two items in the middle

J02230 & J02250 were used.

Thank you. Do you know if the diff pressure sensor before the filter is easy to get to and disconnect?

11 minutes ago, Orman said:

Thank you. Do you know if the diff pressure sensor before the filter is easy to get to and disconnect?

It will be part metal tube and rubber hose, you have the DPF sensor(s) and just need to trace the lines and check 2-3 times to make sure that it is the right line.

 

I am not sure that this process is going to help you clean the oil ash, you perhaps need to email them to check what the product can do.

 

You need pressurised air to pump in product, which you probably won't have either.

 

And you must be able to initiate a static DPF regeneration.

So i decided to just replace the DPF, but the one I want to order is out of stock at the moment. In the meantime as a temporary solution, to stop the car from regenerating all the time while never finishing (I get super high fuel consumption driving it like that), I decided to reset the DPF values in VCDS to trick it that it already had a new DPF fitted.
 

Now the measured/calculated soot and ash all seems to be reading 0g. However, this seems to do the trick until I’ve driven continuously for 20-30 min, then I see that idle rpm is yet again at 1k, and radiator fans running after shutting off.

 

So basically:

 

Before reset of DPF values: It will begin to regen instantly as soon as engine is at operating temp

 

After reset of DPF values: It will begin to regen after 20-30 min of driving after reaching operating temp 

Interesting to know, thanks for that.

 

I reset mine because.............................., well because I am too curious for my own good 😆

 

I didn't notice any difference but the DPF was not blocked.

 

I have since had the emissions "fix" rolled back to a prior software release and it's very very rare now that I am awareof a regen in progress.

 

What you have discovered is a way to offload an afflicted vehicle to an unsuspecting buyer or PX to a dealer.

Hm, 

 

So it hasn’t been long since I reset the DPF values, and now it’s suddenly reading 20g calculated and 24g measured soot. I initiated a regen while driving and then went straight on a dual carriageway driving at 90 km/h 3rd gear at 3500 rpm for 25 km to really get the temps up since it’s -10c here currently. At the end it was reading 8,6g calculated and 16g measured.
 

At that moment, measured soot had stopped decreasing and settled at 16g, and would even start increasing a little bit instead then down again and so on, while still at 3500 rpm with 630-640c DPF input temp and 650c output temp. Then I parked the car and at idle I noticed the measured soot was suddenly dropping rapidly while idling until it settled on 8g and calculated soot at around 4-5g. Just reving it at idle afterwards makes the measured soot to slowly climb up again after that, even more so when I start driving again. Until it reaches the threshold and starts to regen again and I’m back to where I started. 
 

DPF pressure sensor value also jumps from 150 hpa to 350-400 with the slightest rev at idle, which seems kind of odd. 
 

What is weird to me is that if the DPF was really this severely clogged, surely it would impact performance. Car is running absolutely great, and never stores any fault codes on the DPF either. Just constantly regens and never able to finish them off regardless for how long I continuously drive. 

Edited 10 December, 20223 yr by Orman

It absolutely sounds like the DPF is significantly obstructed.

 

I chose my words carefully and did not use clogged or severely, I suspect that they are configured so that even when at their service limit they don't reduce performance or exceed the far more important (to them) fuel consumption and emissions parameters.

 

You could probably drive your vehicle for many more thousands of miles without noticing any loss of performance or decrease in economy if only you could stop the regenning.

 

You could try a partial shunt pipe (a bypass) across the DPF like someone cheating their electric meter but you would need to weld bosses on and there probably isn't the space to do so.

 

Maybe a pair of banjo fittings piped across the sensor bosses?

 

Editted, there would be a slick way of doing it, you would need to do an adaptation of the DPF differential pressure sensor with an artificially increased atmospheric pressure on the free port, you would then get negative values at idle and plausible ones when driving, that might cause a fault code for implausible readings.

 

I mean what is the worst that could happen (written from my time machine 😆)

Edited 11 December, 20223 yr by J.R.

@J.R. Maybe a clamp across the DPF rubber pipe to sensor might fool it enough into thinking the pressure is lower.

Risk is this, if the soot reads 15g after you cheat system, but in reality is 45g+... then the OP might cause a fire as above this threshold this can occur.

I was thinking about a bicycle pump on the open ended ambient pressure pipe.

 

Look back and you will see my sneaky edit!

Just now, J.R. said:

I was thinking about a bicycle pump on the open ended ambient pressure pipe.

 

Look back and you will see my sneaky edit!

🤝Edit is good!

 

All good ideas, my concern is definitly about fire risk.

Probably best if the DPF was not tricked in any way shape or form (unless it's coded out via a remap)

I don’t know why measured soot is decreasing drastically when idling, then increasing again when simply reving the engine or driving. Sounds like a very odd behavior for a clogged DPF. The measured soot content isn’t increasing or decreasing linearly, it’s all over the place. 

Edited 11 December, 20223 yr by Orman

12 hours ago, Orman said:

DPF pressure sensor value also jumps from 150 hpa to 350-400 with the slightest rev at idle, which seems kind of odd.

I did see that, but didn't have time to check over some flow-chart documents for expected values.

 

Could the EGR be having this fluttering effect?  Not sure at the moment...

12 minutes ago, Orman said:

I don’t know why measured soot is decreasing drastically when idling, then increasing again when simply reving the engine or driving. Sounds like a very odd behavior for a clogged DPF. The measured soot content isn’t increasing or decreasing linearly, it’s all over the place. 

It makes absolute sense to me.

 

Firstly forget believing what the system is telling you is happening, start thinking about what sensory inputs it is recieving, namely the DPF diff press sensor, at idle there is little volume of exhaust gases flowing, little back pressure which the not so intelligent system equates with low soot value (it really should have an airflow correction), like any obstructed exhaust system even a potatoe up the tailpipe the back pressure only makes itself known when the engine is revved higher, at that point the DPF DP sensor shows a markedly higher pressure to atmospheric which the system interprets as the DPF having 15G+ of soot, it will not think it is actually blocked with oil ash as it has swallowed the lie it has been told that the DPF is a new one.

@Orman You may wish to use VCDS to generate a log of the rpm vs. pressure readings.

 

Off

Idle

1,000 rpm to 2,500 rpm

 

These are the values that can determine if the sensor is reading sensible values or not.

56 minutes ago, varooom said:

@Orman You may wish to use VCDS to generate a log of the rpm vs. pressure readings.

 

Off

Idle

1,000 rpm to 2,500 rpm

 

These are the values that can determine if the sensor is reading sensible values or not.

Will do that in a bit and report back. Do you know if the pressure sensor is a 2-port one that reads before and after pressure, or a 1-port that compares to atmospheric pressure?

Just now, Orman said:

Will do that in a bit and report back. Do you know if the pressure sensor is a 2-port one that reads before and after pressure, or a 1-port that compares to atmospheric pressure?

Older is a two port, one before and after DPF

 

Newer design one's are singles before DPF and 2nd port is open to atmosphere

2 hours ago, varooom said:

@Orman You may wish to use VCDS to generate a log of the rpm vs. pressure readings.

 

Off

Idle

1,000 rpm to 2,500 rpm

 

These are the values that can determine if the sensor is reading sensible values or not.

Here is sensor readings for off, idle, 1500 rpm and 2500 rpm

 

Off: 0 hPa

Idle: 34 hPa

1500 rpm: 74 hPa

2500 rpm: 95 hPa

 

 

Edited 11 December, 20223 yr by Orman

Also, rpm is going up and staying at 1000 5 mins after a cold start, nothing was up to temp yet so it shouldn’t initiate an active regen. Right when starting up it was idling at 600-700 just 5 mins prior. 

1 hour ago, varooom said:

Older is a two port, one before and after DPF

 

Newer design one's are singles before DPF and 2nd port is open to atmosphere

Not sure what I have, I just took some random pictures. But VCDS does not seem to be displaying two sensor values. 
 

 

Edited 11 December, 20223 yr by Orman

Your values look logical, there is a sensible increase in values as what I would expect.

Resetting your exhaust as you have found out, hasn't stopped the regens, as your soot values are what keeps causing it sadly.

 

I think I mentioned before that my own car hit a 'soot wall' where it couldn't drop below 15g during active regen.

Only since cleaning it has this improved, but probably like your car.. it seems to produce a fair bit of soot for not much driving.

 

 

Sensor(s) location: Remove top cover, and the silver heat shield around DPF sensor(s)

Edited 11 December, 20223 yr by varooom
Additional Information

@varooom Don’t know if I’m allowed to post links, but this is literally a minute after the pictures I took before with the different sensor readings. I decided to rev it to 2500 rpm again and this is what it looked like a minute after:

 

https://streamable.com/z84a7r

13 minutes ago, Orman said:

@varooom Don’t know if I’m allowed to post links, but this is literally a minute after the pictures I took before with the different sensor readings. I decided to rev it to 2500 rpm again and this is what it looked like a minute after:

 

https://streamable.com/z84a7r

Smoking like a chimney, with my own car, it definitely adds soot at 2,500rpm limiter.

 

That's a no-load scenario, to be expected.

 

At idle (1,000rpm for you now) I suspect soot measured would decrease.

10 minutes ago, varooom said:

Smoking like a chimney, with my own car, it definitely adds soot at 2,500rpm limiter.

 

That's a no-load scenario, to be expected.

 

At idle (1,000rpm for you now) I suspect soot measured would decrease.

But this time around, sensor was reading 143 hPa compared to 95 hPa just a minute earlier, both at 2500 rpm idle.

 

Might have to undo the DPF and give it a wash instead, I’m not too keen driving it in constant regens while waiting for the aftermarket DPF to be back in stock. Was hoping that resetting the DPF values would be a temporary fix until then, but not even that seems to be working. 

4 minutes ago, Orman said:

But this time around, sensor was reading 143 hPa compared to 95 hPa just a minute earlier, both at 2500 rpm idle.

 

Might have to undo the DPF and give it a wash instead, I’m not too keen driving it in constant regens while waiting for the aftermarket DPF to be back in stock. Was hoping that resetting the DPF values would be a temporary fix until then, but not even that seems to be working. 

I dare say you would have added some soot during revving process, so it's just reading that.

The EGR will also be impacting pressure readings as it does it's thing I suspect.

 

Resetting the exhaust is a basic counter of how much life (estimated) that exhaust has.

So in real life as you have seen, it doesn't change your regen behavior, as that is down to soot production.

 

 

My car still wants to regen often, but it's primarily used once a week to drive around town at low speed as I am teaching my son how to drive.

Just the soot now will drop under 15g thankfully as it drives about, no 'hard floor' so to speak.

100% down to cleaning off the soot that built up from previous owner, not that I am helping it by only doing short journeys, but I am aware of that fully.

On 11/12/2022 at 16:45, varooom said:

I dare say you would have added some soot during revving process, so it's just reading that.

The EGR will also be impacting pressure readings as it does it's thing I suspect.

 

Resetting the exhaust is a basic counter of how much life (estimated) that exhaust has.

So in real life as you have seen, it doesn't change your regen behavior, as that is down to soot production.

 

 

My car still wants to regen often, but it's primarily used once a week to drive around town at low speed as I am teaching my son how to drive.

Just the soot now will drop under 15g thankfully as it drives about, no 'hard floor' so to speak.

100% down to cleaning off the soot that built up from previous owner, not that I am helping it by only doing short journeys, but I am aware of that fully.

I decided to just remove the DPF and send it off to get it professionally cleaned. Will begin with that in the coming days. I haven’t had the car up on a lift yet since I bought it, and seen how things are located underneath. Do you know if it’s enough to lower the subframe to be able to get the DPF out, or do I have to completely drop the subframe altogether?