I have recently purchased a late MK2.5 Octavia VRS CR170. The previous owner clearly adored the car, it's immaculate with a ton of receipts for work etc.

 

I found in the receipts, an eco remap to 203bhp with an EGR and DPF delete. Brilliant I thought, I don't need to worry about those. The issue is, I think the car is attempting to do a regen still. It is cold 6-8c outside and sometimes, after a short journey, the fans are running when I turn the engine off. When it's idling, it's sitting at 1,000 rpm. That is a regen isn't it?

 

I called the garage I bought it from who confirmed the DPF is still on the car and it passes an MOT. It doesn't smoke at all which would kind of back that up.

 

Is it actually possible to map out a DPF but still have a regen cycle?

I know this is a late reply. 

My concern here is there are receipts for DPF delete, but the DPF is still on the car.  The DPF regens based on back pressure from soot build up.  If you have no DPF, then you shouldnt be building up soot, so regen shoudnt trigger.  I would suggest the DPF is still present, and working as designed.

The fans run after engine switch off, to cool the system as it will be hot from a regen or part way through a regen.  You can do a regen, and keep driving an the system will cool down itself,  When you turn off the car, the fans wont be running.

Has the EGR been blanked as well, or were the receipts just for optional but work wasnt done?  If you really want to push power output, then go the egf and dpf removal route.  You can get plenty of power/torque from the CR170 motor with just a remap and leave everything else in place.

On 13/01/2025 at 09:59, spud75 said:

I know this is a late reply. 

My concern here is there are receipts for DPF delete, but the DPF is still on the car.  The DPF regens based on back pressure from soot build up.  If you have no DPF, then you shouldnt be building up soot, so regen shoudnt trigger.  I would suggest the DPF is still present, and working as designed.

The fans run after engine switch off, to cool the system as it will be hot from a regen or part way through a regen.  You can do a regen, and keep driving an the system will cool down itself,  When you turn off the car, the fans wont be running.

Has the EGR been blanked as well, or were the receipts just for optional but work wasnt done?  If you really want to push power output, then go the egf and dpf removal route.  You can get plenty of power/torque from the CR170 motor with just a remap and leave everything else in place.

I have ordered VCDS to see if I can see the DPF information soot level etc. If I can then it hasn’t been mapped out. 
 

It is definitely still on the car and it seems to be regenerating every 2-300 miles. 
 

The car doesn’t feel 170bhp to me. My previous 320d was 210bhp and the Octavia doesn’t feel much different. 
 

EGR valve is still in place no blank fitted. 

Perhaps it was a misunderstanding and it was the EGR that was mapped out?

 

They can be blanked without removal, in fact its the preferred way as it looks stock, a thin shim steel blanking plate is used the same size and form as the original flange gasket.

 

Mine has been disabled by using an emulator/simulator which has the same effect as mapping the EGR out, the car still performs DPF regens but very very rarely as I also had the engine software rolled back to the original emissions cheating version, my vehicle has been remapped.

 

From what you describe you have the ultimate, more power, no EGR and infrequent regens, - enjoy it to the full

Edited 16 January, 20251 yr by J.R.

16 minutes ago, J.R. said:

Perhaps it was a misunderstanding and it was the EGR that was mapped out?

 

They can be blanked without removal, in fact its the preferred way as it looks stock, a thin shim steel blanking plate is used the same size and form as the original flange gasket.

 

Mine has been disabled by using an emulator/simulator which has the same effect as mapping the EGR out, the car still performs DPF regens but very very rarely as I also had the engine software rolled back to the original emissions cheating version, my vehicle has been remapped.

 

From what you describe you have the ultimate, more power, no EGR and infrequent regens, - enjoy it to the full

The receipt is from 2020 so maybe the DPF delete was reverted, I am not sure but it definitely says….

 

Economy remap 203bhp

EGR delete tick

DPF delete tick

 

The exhaust tips internally are quite sooty which raised my suspicions when my mechanic said the DPF is still on the car. 
 

The car certainly does not sound like the DPF has been hollowed out that’s for sure and it does not smoke at all. 
 

A VW specialist that serviced it said if the map is good at 200bhp a CR170 shouldn’t smoke anyway. 
 

I guess VCDS will prove what is going on. 

Yes VCDS should reveal all, if it shows values for soot, oil ash etc then it thinks the car has one which indeed it does visually, you could try a forced regen but when I did that it refused saying a parameter was not met without saying what said parameter was, par for the course with the chocolate teapot.

 

Keep an eye on the readings and also the DPF differential pressure, the values for soot and ash are calculated and not real, the diff pressure is real, if you see the soot and ash reading lower than they were (regen triggered at around 22g of soot I think) and also a lower diff pressure then its reasonable to deduce that DPF regens are  being commanded and doing what they should.

 

You could also look at the commanded and measured values of the EGR valve position, if it says N/A then its been coded out in as much as the ECU doesnt think it exists any more, maybe the coding is a software patch that pretends it is still there, in which case you can manually command it using Output Tests and feel it to see if the motor turns, in my case with the emulator simulator the EGR wont budge but the output from the position sensor (false output from simulator) will tell the ECU that it has moved by the correct amount.

 

I hope the above makes some sense, I know what my black box (emulator) does but I dont know what the tuners do when they claim to "map out" something, I am speculating with an educated guess.

1 hour ago, J.R. said:

Perhaps it was a misunderstanding and it was the EGR that was mapped out?

 

They can be blanked without removal, in fact its the preferred way as it looks stock, a thin shim steel blanking plate is used the same size and form as the original flange gasket.

 

Mine has been disabled by using an emulator/simulator which has the same effect as mapping the EGR out, the car still performs DPF regens but very very rarely as I also had the engine software rolled back to the original emissions cheating version, my vehicle has been remapped.

 

From what you describe you have the ultimate, more power, no EGR and infrequent regens, - enjoy it to the full

I refused the remap so mine is still on original emissions cheating. At 5L/100km i am doing my bit for the environment anyway.

I still havent got around to doing the performance remap.  I would love it, but i can  spin the wheels in 2nd gear in the wet with traction control on, and it chirps changing up to third, so do i NEED the extra???? Probably not, I def want it though...

 

7 hours ago, J.R. said:

Yes VCDS should reveal all, if it shows values for soot, oil ash etc then it thinks the car has one which indeed it does visually, you could try a forced regen but when I did that it refused saying a parameter was not met without saying what said parameter was, par for the course with the chocolate teapot.

 

Keep an eye on the readings and also the DPF differential pressure, the values for soot and ash are calculated and not real, the diff pressure is real, if you see the soot and ash reading lower than they were (regen triggered at around 22g of soot I think) and also a lower diff pressure then its reasonable to deduce that DPF regens are  being commanded and doing what they should.

 

You could also look at the commanded and measured values of the EGR valve position, if it says N/A then its been coded out in as much as the ECU doesnt think it exists any more, maybe the coding is a software patch that pretends it is still there, in which case you can manually command it using Output Tests and feel it to see if the motor turns, in my case with the emulator simulator the EGR wont budge but the output from the position sensor (false output from simulator) will tell the ECU that it has moved by the correct amount.

 

I hope the above makes some sense, I know what my black box (emulator) does but I dont know what the tuners do when they claim to "map out" something, I am speculating with an educated guess.

Thanks this is a great help. 
 

The ideal situation would be the DPF is still operating as normal and the results are all ok and the EGR is mapped out. 
 

Fingers crossed VCDS arrives tomorrow and I can work out what the tuning has or hasn’t done. 

Ok, update for you all. VCDS has arrived and right on que as the car has started regenerating again.

 

I waited for the regeneration to stop and the results are as follows…..

 

Particle filter pressure - 3mbar

Distance since last regen - 10km

Oil ash volume - 125ml

Carbon mass (spec) 8.4

Carbon mass (act) 0

 

So it seems the DPF is working, my only query now is why is the carbon mass actual zero?

Its a calculated figure based on the particle filter back pressure which is nice and low.

 

You need to find the parameter for oil ash volume service limit, it could be that 125ml is beyond the maximum, it does not help that they keep changing the descriptions and units of measure.

 

Do the measurements again before another 10km has passed and see how far it says the vehicle has travelled, mine is in meters and you have to divide by 1000, you cant trust anything in VCDS to be what it says it is.

 

The soot (carbon mass?) should go up to 22.5 or 25g before a regen is triggered.

 

If it builds up slowly then your DPF is working OK and if the oil ash volume (estimated) is too high maybe you need to do the adaptation in VCDS to tell it that it has a new DPF fitted, that might make a difference.

They have even changed "calculated" which was a true term for "specified" the muppets!

I have read the TDi’s that had the ‘correction map’ regenerate a lot more than the ones that had the cheat software. My Octavia has the correction software, found a printout from Skoda with a disclaimer in the paperwork. 

 

At the moment it seems every 250-300 miles it regenerates. 
 

Regarding the oil ash reading, it seems nobody really knows. It seems 175ml gets banded about but then somebody got there TDi up to 240ml before the light came on. 
 

Somebody hit 400ml in the US apparently!
 

 

1 hour ago, J.R. said:

They have even changed "calculated" which was a true term for "specified" the muppets!

It is frustrating when trying to follow guides that are a few years old!

I paid to have the emissions fix software rolled back, I never hear an interrupted regen now (twice in 3 years), I think its happening every 1000kms or maybe 1000 miles which is a safety default, my DPF never builds up enough soot to trigger a regen due to the passive regeneration, yours would not either but for the software update.

 

250-300 miles means the DPF is working well.

 

When you are more used to VCDS try output tests on the EGR to see if you have one and if its doing as commanded, hopefully it will not!!!!

What are the down sides of the correction map?

 

I have seen some people report an increase in fuel consumption due to the regening and some have even said the engine sounds different. 
 

Did it cost much to have it removed?

Nothing but upsides for me.

 

Cost was expensive, had I been able to have my remap done at Celtic Tunings headquarters it would have been done free with the remap but due to the covid restrictions and my moving house the remap was done by one of their agents.

 

A couple of years later I dropped in on the offchance to ask the question, I had 20 minutes to spare before my stepmothers funeral nearby the best I could hope for was to go back later in the day but they did it there and then, it cost £250 but I was not going to argue given the service I recieved.