Diesel question

Started by BazaJT, 07 September 2026, 09:33:32

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BazaJT

Last Saturday I bought a diesel engined car(first diesel I've owned in 50+ years of motoring) on a 56 plate it has a dpf. The question is how do I tell if/as/when it's doing a regen? It was a 130 mile trip home mostly motorway(with variable speed limits)and I didn't notice any difference in performance or anything so are there any signs to look out for to say it's doing/has done a regen? In case it makes a difference it's a Volvo d5 185hp S80.

Doctor Gollum

Higher idle speed and a load of shite coming out of the back. Also lots of heat, so possibly better to keep driving rather than shutting it off. This won't be convenient but that's the point.
Onanists always think outside the box.

YZ250

Under normal driving you'll barely notice, unless you constantly monitor instant fuel consumption and happen to notice the drop as it chucks some in to burn. It's when you stop that you'll notice, assuming it's trying to regen when you park up. The car will idle slightly higher, smell excessively hot, the cooling fans will be running flat out, even after you've switched off the engine, and may run for several minutes after.
Of course, as Al said above, if it regens as you're driving, especially in a higher rev range, you'll probably never notice any of these things. On the other hand, if it never does any of the above, then the dpf could have been gutted and mapped out.  ::)
My fun car is a 2020 Bmw F32 430d M Sport with indicators.
My cruiser is an Audi A6 Avant S Line Black Edition with indicators.

Doctor Gollum

Quote from: YZ250 on 07 September 2026, 10:53:39
Under normal driving you'll barely notice, unless you constantly monitor instant fuel consumption and happen to notice the drop as it chucks some in to burn. It's when you stop that you'll notice, assuming it's trying to regen when you park up. The car will idle slightly higher, smell excessively hot, the cooling fans will be running flat out, even after you've switched off the engine, and may run for several minutes after.
Of course, as Al said above, if it regens as you're driving, especially in a higher rev range, you'll probably never notice any of these things. On the other hand, if it never does any of the above, then the dpf could have been gutted and mapped out.  ::)
Surely one as reformed as you wouldn't possibly know about such things >:D
Onanists always think outside the box.

TheBoy

As YZ says, normally you won't notice, unless its only going down the local shop all the time, in which case you have bought the wrong car.
Grumpy old man

YZ250

Quote from: Doctor Gollum on 07 September 2026, 11:15:40
.......
Surely one as reformed as you wouldn't possibly know about such things >:D

My dpf remains unmolested.  :y  (I can't say the same for the ECU/TCU though  :-X  ;D ) The other family diesel however, appears unmolested.  ;) ;D  It also appears to have lost its memory as it's forgotten that it's supposed to regen.  ;D 
My fun car is a 2020 Bmw F32 430d M Sport with indicators.
My cruiser is an Audi A6 Avant S Line Black Edition with indicators.

Marks DTM Calib

Quote from: YZ250 on 07 September 2026, 11:33:24
Quote from: Doctor Gollum on 07 September 2026, 11:15:40
.......
Surely one as reformed as you wouldn't possibly know about such things >:D

My dpf remains unmolested.  :y  (I can't say the same for the ECU/TCU though  :-X  ;D ) The other family diesel however, appears unmolested.  ;) ;D  It also appears to have lost its memory as it's forgotten that it's supposed to regen.  ;D

That could be interesting at the end of next year...... :y ;D

YZ250

Quote from: Marks DTM Calib on 07 September 2026, 15:37:30
Quote from: YZ250 on 07 September 2026, 11:33:24
Quote from: Doctor Gollum on 07 September 2026, 11:15:40
.......
Surely one as reformed as you wouldn't possibly know about such things >:D

My dpf remains unmolested.  :y  (I can't say the same for the ECU/TCU though  :-X  ;D ) The other family diesel however, appears unmolested.  ;) ;D  It also appears to have lost its memory as it's forgotten that it's supposed to regen.  ;D

That could be interesting at the end of next year...... :y ;D

I do recall you mentioning that they are tightening things up regarding emissions for future MOT's.  :y  It'll be interesting to see what happens.
The vehicle in question was done years ago as it had a clogged dpf, and as it had a connection flange very close to an open end, it was easy to remove the honeycomb without any outer damage. The remap was done due to the pressure changes and to delete dpf and regen. As you say, the technology is changing to stop this type of thing.  :y
My fun car is a 2020 Bmw F32 430d M Sport with indicators.
My cruiser is an Audi A6 Avant S Line Black Edition with indicators.

Marks DTM Calib

Quote from: YZ250 on 07 September 2026, 16:10:43
Quote from: Marks DTM Calib on 07 September 2026, 15:37:30
Quote from: YZ250 on 07 September 2026, 11:33:24
Quote from: Doctor Gollum on 07 September 2026, 11:15:40
.......
Surely one as reformed as you wouldn't possibly know about such things >:D

My dpf remains unmolested.  :y  (I can't say the same for the ECU/TCU though  :-X  ;D ) The other family diesel however, appears unmolested.  ;) ;D  It also appears to have lost its memory as it's forgotten that it's supposed to regen.  ;D

That could be interesting at the end of next year...... :y ;D

I do recall you mentioning that they are tightening things up regarding emissions for future MOT's.  :y  It'll be interesting to see what happens.
The vehicle in question was done years ago as it had a clogged dpf, and as it had a connection flange very close to an open end, it was easy to remove the honeycomb without any outer damage. The remap was done due to the pressure changes and to delete dpf and regen. As you say, the technology is changing to stop this type of thing.  :y

The law changes middle of next year to make it illegal (it isn't officially illegal at the moment......), the proposal then is to give six months grace and introduce an MOT check (the tech is well proven, the TUV in Germany have been doing it for years).

But it is the usual £1000 fine if spotted by VOSA and a staright fail at an MOT

YZ250

Quote from: Marks DTM Calib on 07 September 2026, 16:22:09
........
The law changes middle of next year to make it illegal (it isn't officially illegal at the moment......), the proposal then is to give six months grace and introduce an MOT check (the tech is well proven, the TUV in Germany have been doing it for years).

But it is the usual £1000 fine if spotted by VOSA and a staright fail at an MOT

Wow, talk about spooky.  :o  I have not googled this, I have not discussed this, but look what just popped up in my news feed. I'm starting to believe the conspiracy theories regarding the Covid jab being a tiny micro chip now.  ;D  ;D ::)

https://www.gov.uk/government/consultations/in-use-emissions-of-road-vehicles-regulating-environmental-impacts/regulating-environmental-impact-of-in-use-emissions-of-road-vehicles

The general feeling towards these new rules appears to be that the government know that many many people genuinely do not want an EV. The lack of EV uptake has thrown them in to turmoil and no matter what they say about them selling fantastically, we all know that's just not true. Most car manufacturers have approached their governments to plead with them to see reason, as they know it's financial suicide at this point in time. BMW saying that the IX3 is their best selling EV cuts no ice either, it just means that their other models are selling less.

So, to cut to the chase:
What do the government do if people aren't buying EV's? Well, they could always tighten the emissions laws for MOT time so that a vehicle with 100K on it must have the **exact same emissions as when it left the factory brand new**. Hmm, that gets rid of a fair few ICE vehicles, but not enough to keep them happy. I know, we'll give the people X amount of chances at MOT time to bring their vehicle within emissions requirements, and if they go over that amount of chances over multiple visits, the vehicle fails automatically and gets scrapped.
The logic behind it is ........... you won't be able to buy a new ICE replacement as they'd have banned the sales of them by then, and buying second hand would be an emissions gamble.  ::)  So what's your alternative...... you buy an EV.  ::)

**
Bearing in mind that VAG (German) couldn't even produce a brand new car that didn't flout the emissions rules, so owners would have no chance at 100K.  ;D  And for what it's worth, I don't believe the other well known German brand were completely innocent either, as during 'Dieselgate' they added the SCR Adblue system to the same non-Adblue engines on the mid year build phase, which would not have been a cheap exercise.  :-\  Just my theory anyway.  ::)

My fun car is a 2020 Bmw F32 430d M Sport with indicators.
My cruiser is an Audi A6 Avant S Line Black Edition with indicators.

Andy B

too late to respond now though ....

''How to respond
We will only accept responses received before the closing date: 11:59pm on 6 September 2026.''

YZ250

Quote from: Andy B on 08 September 2026, 08:34:39
too late to respond now though ....

''How to respond
We will only accept responses received before the closing date: 11:59pm on 6 September 2026.''

I'll admit that I skim read it, I just thought it quite ironic that it popped up as it had been mentioned on here.  :y
I'll read it properly today.  ;D  :y
My fun car is a 2020 Bmw F32 430d M Sport with indicators.
My cruiser is an Audi A6 Avant S Line Black Edition with indicators.

BazaJT

Thanks for the replies people. I'll take not of it's normal idle speed so I'll know if the tickover is higher than normal when I pull up somewhere. Yes TB although never owning a diesel before I was aware that diesels with a dpf are not good for short stop/start use,but thanks for mentioning it as it never hurts to be told/reminded. My V70(petrol)will be used for the local trips(shopping etc) and the S80(diesel)for the distance(40+miles). Now just got to sort a split cv boot.

Marks DTM Calib

You have to consider that VAG did what they did to save THEM money and make bigger profits.

They did not fit SCR systems and put very large scale EGR on instead to get the NoX down, what this did is make the engines awful to drive. So they only operated the large scale EGR when the steering wheel had not moved for greater than a set time period (60 seonds from memory) e.g. when the car is strapped to a rolling road test rig with the steering wheel clamped.

When they rolled out a 'fix' (remember they met the legislation!) they increased the EGR a bit to get the NoX down a bit (and hence why the software update slugged cars).

Removing a DPF effectively takes diesel particulate levels to that of Euro 4 and nobbling the SCR takes NoX to a similar level.

I suspect the MOT testing will be to a level well above the Euro6 test standard but, massively below that of Euro 4, probably around the Euro 5 levels.

To put some magnitues, Euro 4 allows three times the NOx and more than five times the particulates compared to Euro 6

Andy B

Quote from: YZ250 on 08 September 2026, 09:07:55
Quote from: Andy B on 08 September 2026, 08:34:39
too late to respond now though ....

''How to respond
We will only accept responses received before the closing date: 11:59pm on 6 September 2026.''

I'll admit that I skim read it, I just thought it quite ironic that it popped up as it had been mentioned on here.  :y
I'll read it properly today.  ;D  :y

I only skimmed though it myself ....  :y