Running a diesel car with DPF on not many miles per journey/year?

neilmcl

JustAnotherSaver said:

AdrianC said:

It's also worth remembering what triggers DPF regeneration. HEAT.

Just "going on a motorway" does not necessarily get an exhaust hot. Something like a diesel SQ5 will be barely tickling along sitting at 70mph on a clear m'way. Plenty of cooling airflow underneath, almost no throttle, very few revs, very little load. You'll probably find it'll get hotter in slow moving urban traffic, especially if given a bit of squirt into gaps or if they turn stop-start off...

@neilmcl - do you have an interest in detailing cars or am I off the mark and its just a coincidence? Searched for something at the weekend and saw your name. 

I've been known to frequent the detailingworld forums 😉

clive0510

AdrianC said:

clive0510 said:

I don't do high mileage in my peugeot and thats got a dpf. with add blue. also has eloys system

It won't have both Eolys and AdBlu. It'll have one or the other, depending on age.

it has both. in fact its not eloys. its the later stuff which is called powerflex. I work for peugeot main dealer and have checked it on peugeot service box.

macman

The way it's 'professionally' done* is to remove the DPF, cut it open and remove the guts, then weld it back up and replace it. The ECU is then remapped. Once the heat shield is back on, no MOT tester can possibly detect it, as the inspection is purely visual, with no disassembly allowed. The only giveaway would be if it failed the emissions test, and that wouldn't confirm the absence of a DPF anyway.

* allegedly: never tried it myself, honest guv...

AdrianC

JustAnotherSaver said:

Is there anything about the MOT that fails a car without a DPF that should have one or is the answer "depends"? 

If there's a big section in the exhaust where a box should be with a filter inside and this has been clearly cut out and welded back up then I'm not talking about that. 
I mean done in such a way that it appears the DPF is still there. A blank fitted perhaps.

https://www.gov.uk/guidance/mot-inspection-manual-for-private-passenger-and-light-commercial-vehicles/8-nuisance#section-8-2-2-1

8.2.2.1. Exhaust emission control equipment

You only need to check components that are visible and identifiable, such as diesel oxidation catalysts, diesel particulate filters, exhaust gas recirculation valves and selective catalytic reduction valves.

If a diesel particulate filter has clearly been cut open and rewelded, you should reject it unless the vehicle presenter can show evidence that there was a valid reason to cut it open, such as for filter cleaning.

(a) Emission control equipment fitted by the manufacturer missing, obviously modified or obviously defective - Major
...
(c) Evidence that the diesel particulate filter has been tampered with - Major

Also spoke to someone who had just bought a Golf 170 on an 08 plate. He said he was going to have the DPF mapped out on it. 

"Mapping it out" says to the ECU "DPF? What DPF?" - there's none fitted, don't try to regen it, and don't worry about the pressure readings. That's not going to end well, because it WILL clog, far sooner than it would if he hadn't mucked with it.

So that mapping needs to be backed up with a physical DPFectomy. Normally, these days they drop the exhaust and go through the top. Everything looks untouched from below. Until it comes time to put it on the emission tester, and check the smoke opacity... And, guess what? The lack of DPF doesn't filter the particulates!

clive0510

macman said:

The way it's 'professionally' done* is to remove the DPF, cut it open and remove the guts, then weld it back up and replace it. The ECU is then remapped. Once the heat shield is back on, no MOT tester can possibly detect it, as the inspection is purely visual, with no disassembly allowed. The only giveaway would be if it failed the emissions test, and that wouldn't confirm the absence of DPF anyway.

* allegedly: never tried it myself, honest guv...

yeh, so with the dpf internals gone, the car will almost certainly fail the mot, meaning it can't be legally used on the road.

JustAnotherSaver

Hmm, is that fairly new that that had come to being then? As I remember reading a few years ago about folk whipping their DPF out and passing no bother. 
If they ramped up the criteria for a pass to expose people doing this then that'd make sense that it'd now fail. 

@neilmcl yeah I was going to wash the car on Sunday and had a load of stuff to do. It was about 9am so I googled acceptable time for pressure washing on a Sunday. I found that you were one of the later ones, not wanting any noise before 10am  

[Deleted User]

I've ended up with this situation, I was doing a regular run down country lanes / dual carriageways to a job (albeit 18 mile around unless I went to the gym) but for change of job I commute by bike as I don't want to drive 6 miles into the city in rush hour as it'll trash the engine. At least pro-covid I ran it at weekends for sport, often doing round trips up to 150 miles plus going to see parents is 70 miles each way so it works out pretty well and not had any problems after 6 years. Hoping the lock down ends so I can at least take it out for a good run or two

AdrianC

JustAnotherSaver said:

Hmm, is that fairly new that that had come to being then?

May 2018.
https://www.gov.uk/government/news/mot-changes-20-may-2018

daveyjp

Unfortunately my last diesel ownership came to an end when I dropped from 20k to about 8k miles a year.  The car hated it so I went back to petrol.

I'm sure DPF tech has improved in ten years and I could run a modern diesel, but for the miles I now do a diesel makes absolutely no sense.

Scrapit

clive0510 said:

macman said:

The way it's 'professionally' done* is to remove the DPF, cut it open and remove the guts, then weld it back up and replace it. The ECU is then remapped. Once the heat shield is back on, no MOT tester can possibly detect it, as the inspection is purely visual, with no disassembly allowed. The only giveaway would be if it failed the emissions test, and that wouldn't confirm the absence of DPF anyway.

* allegedly: never tried it myself, honest guv...

yeh, so with the dpf internals gone, the car will almost certainly fail the mot, meaning it can't be legally used on the road.

Er, what? Certainly? That is definitely not the case.