Strange thing happened today; the car spontaneously performed a regen at 75%/20g of soot loading and dropped to around 60%/16g and the engine had smoothed out before I had to  switch off. 

 

Mindful a regen had been interrupted I opened Carista and performed a forced regen for the 10 mile drive home - the regen stopped at around 9 miles, but when I got home I found the soot loading was back to 75%/21g of soot.

 

How can the soot load increase so much in that short drive (over 40mph, over 2k rpm), I also noticed the fuel gauge dropped about 1/8th of a tank in that short time even though consumption was an indicated 45mpg

 

Last regen was 250 miles ago and burnt down from 22g to 6g of soot. 

How many mile has the engine done?

110k miles. 

Over tickover it runs smoothly, pulls very well and flies - economy isn't great though at about 45mpg average. 

Pulling from just off tickover in 1st 2nd and 3rd it rattles and knocks badly, in 4th and 5th below 1500rpm it just pulls quietly. 

Frustrating 

I don't know what to suggest other than saying that the regens are triggered by the calculated soot levels and not the measured ones, now that mine no longer has EGR it regens when it has calculated there is 24g of soot yet the measured quantity is only 3 or 4g.

 

Mine is regenning at about 100km or 62 miles, it has had the emissions fix, it clearly does not need to but thinks that is does because it wont use the measured values.

 

My other concern was the oil ash limit, is it going to stop working because it thinks it has reached its limit? It reports on VCDS in litres and not grammes and adds 0.1l every 10K miles, I'm at 102K miles and it showing 1 litre I think, I cant find the service limit figure anywhere.

 

Then looking through some obscure measuring blocks I found ones that had the calculated oil ash and the service limit in the same units, it might have been grammes, that showed my DPF as 60% full (calculated not measured figure) so will it shut down at say 150k because it thinks it is blocked or when it really is blocked?

 

What figure is yours showing for the oil ash residue?

Edited 3 January, 20224 yr by J.R.

@J.R. My ash residue is showing 59g and 83% at 110k. 

 

A friend with DPF issues used Normfest DPF100 and then reset the ash limit to zero - this was some months ago with no ill effects, worth a gamble at £50 a tin?

 

Damned car started a regen again today, started at 22g soot and stopped at 16g calculated, measured is -1g ?? 

 

Fuel usage is mental; 25% of the tank in 60 miles, but showing 45mpg - so the fuel must be being used up during regen. 

 

I feel I have more deep seated issues than just the DPF; I think I have injector problems (sounds like a tractor during regen and smokes a lot), it knocks at low revs and tickover jumps around a lot starting from cold. 

 

 

That sucks!

 

I wont pay £50 for snake oil but I definitely will reset the ash limit in case it does decide game over when its calculated reading reaches the limit which I still don't really know.

 

As long as my DPF differential pressure remains OK I don't want the thing shutting down because an algorithm has decided that it is full when it clearly can't be.

 

With that in mind I strongly recommend that you do the adaptation for the DPF DP sensor, it creates a new value for the offset, basically it is a calibration, without the engine running it compares the pressure readings on both sides of the sensor and I think also to the MAP sensor, both sides should be the same if the engine is not running and nobody is blowing up the exhaust pipe, it creates the offset to be used in the calculations.

 

I have done mine a couple of times, the first time there was quite a difference, the second just a minor variation.

 

It could be that your regens are being triggered before the limit is reached if the differential pressure goes too high when running, that could be because your DPF is in fact quite full with oil ash which cannot be burnt away or it could be because the differential pressure reading is wrong and the sensor needs a true offest figure applied.

 

When I have lied to my ECU that I have fitted a new DPF it will be interesting to see if the frequency of regenerations decreases.

All that fuel being used on the regens, some of it will be finding its way past the piston rings and into the sump oil, I recommend you keep a very close eye on the dipstick level and change the oil if you see any increase or a decrease in oil comsumption if your car was a drinker before.

 

The fuel is injected during the exhaust stroke and does not combust until it reaches the bonfire in the DPF, some will find its way to the sump, thats the reason I am looking at all avenues to reduce the frequency of my regens, an emissions fix roll back will be the most effective I feel but since covid my journey profile has become short local trips, that will soon change with my moving to another area.

Thanks for your updates, the verdammt car started a regen from cold tonight, and once my appointment was concluded it regened on the way home, again with a cold engine! But the soot load didn't move more than 0.5g of soot and actually rose whilst I was sat on the drive waiting for the process to conclude!

 

To improve the drive I have found an old copy of vcds 15.7.1 today which allowed me to raise the tickover slightly (by 30rpm), this has smoothed low speed running but I've had no chance to try it properly due to SNOW on the Worcs hills tonight!

 

Your experiences are very interesting, I will certainly adopt the differential pressure sensor tomorrow, I thought this was a once-off deal with a new sensor - I've not heard of an old sensor having this procedure. 

 

It may be snakeoil but as I have it I may as well try Normfest DPF100, it this goes in the top of the DPF once the sensor is removed and may well take some soot from the blow side of the turbo too. 

 

I am planning a air, oil and fuel filter swap and oil change this month - I'll check levels tomorrow.

 

I will give the car to the local garage to have the injectors checked professionally, I can get the results off vcds but the figures man nothing to me. 

 

I think you have an EGR simulator fitted with an EGR blank? Is this helping?

 

I have a remap with a so-called EGR delete and an EGR blank fitted to the head, however I'm beginning to doubt whether this decision has taken me down a blind alley. 

I had not heard of anyone adapting an old sensor but it did seem to be giving odd readings, it may have been replaced before but not calibrated, its something I will do periodically.

 

If my DPF seemed blocked and was giving a large DPF DP reading I would certainly use a product but it doesn't seem restrictive now.

 

EGR emulator does its job, the car runs a little better, I see a big difference now between the high calculated and the much lower measured soot values, the car thinks it is operating the EGR, frequently because its had the emissions fix so it thinks the soot values are high and regens far too frequently.

 

So it is I believe helping to prevent the DPF getting clogged, unfortunately the ECU even though it is being told the true information is sticking to its calculated values from the algorithm.

 

I will definitely try telling it that I have fitted a new DPF, what could possibly go wrong?.........................

 

Answers on a postcard please!

15 hours ago, J.R. said:

What could possibly go wrong?........................

 

 oh please, don't get me started ...

 

Today the car performed a regen on the way to work with red DPF light on the dash but only burnt down to 15g - VAGDPF showed no more fuel was being injected, the soot figure remained stable so I gave up and switched off.

 

On the way home the yellow DPF light came on instantly even with a cold engine, and the car performed horribly until the light went off at which point the soot was down to 8g   and the car was running as smoothly as ever.

 

Since Sunday the car has travelled about 80 miles and sunk over half a tank of super diesel. My finances will roll over a die unless something changes - I think I have at least one duff injector.

 

So ... it's booked into my local (trusted) garage for some diagnostics. 

Local garage diagnosed one injector heavily overfuelling; 3 running at approx 0.6 and correcting themselves and the other sitting steady at 2.7.

A replacement is on a 5 day back order!

 

 

Edited 11 January, 20224 yr by b1ackb1rd
More info

Another regen today; 17g to 6.7g in 36 miles and 1/3 of a tank of fuel.

 

In the midst of this mess it went into limp mode and stalled driving up a steep hill in traffic, which wasn't nice.

 

A few things have struck me as strange and contra to what is stated in the manual; 

 

1) regens start from cold, within half a mile 

2) a regen started today when the fuel reserve light was on (30 miles left)

3) when the regen had completed with 6.7g and 28% still left, the red DPF light came on, but VAG DPF showed no fuel being injected

 

 

1 hour ago, gumdrop said:

 

 

I had an inkling that removal of DPFs was illegal, but I just needed a source to do so.

 

https://www.bbc.co.uk/news/uk-41761864

 

Hope this helps.

I use this method to get rid off the ash from blocked DPFs had very good results with Skodas and MInis
 

 

I've got a can of Normfest DPF100 that I've been intending to use, having seen the goo that comes out of the exhaust I won't be doing it on MY drive

20 hours ago, b1ackb1rd said:

I've got a can of Normfest DPF100 that I've been intending to use, having seen the goo that comes out of the exhaust I won't be doing it on MY drive

The best foaming spray I have used is Innotec DPF Doctor

But for the price of the Vtech Fluid I can do 5 cars for the same price as I can of above 

Just bought a cheap 2ltr pump from Amazon

New injector fitted and coded today - what a difference !

 

Fuel economy is immediately up, but oddly the car no longer 'feels' remapped. 

 

A regen is due in the next 100 miles or so, that will be the acid test.