Quote:

I'd suspect the DPF now given high exhaust back pressure and rapid soot load.

JayGee - I'd be grateful if you would expand.

Do you mean that the DPF is full of ash? I thought this scenario would be highlighted with an error code as I believe that there is a DTC for this, P242F-00.
Or do you mean that there could be some other problem with the DPF, that mean it will to function as intended? I've read somewhere on here about someone who's DPF had baked on soot/ash that could not be removed?

I had always planned to get my DPF cut off and cleaned properly as a metaphorical 'reset' under my ownership so am happy to continue. I just don't want to do this until I ca be relatively certain that there isn't something else causing an issue 'upstream' as, if so, it would be a waste of time/money.

TYIA!  Andy

2010 4.4TDV8 Vogue SE in Santorini Black with Ivory interior
2017 Audi SQ5 3.0 V6T Quattro in Volcano Red
2001 Audi Allroad 2.5 TDI manual with low-range in Highland Green. Currently SORN whilst undergoing some serious restoration!

Is the pressure sensor upstream of the CAT? 2012 TDV8 Vogue (L322)

I don’t think so. The pressure sensor is the differential pressure sensor shown in the picture at 9. It takes a high pressure pipe upstream of the DPF and a low pressure feed from downstream of the DPF. Although not labelled, I assume the CAT is the cylinder upstream of the DPF?

Click image to enlarge

The CAT is indeed the cylinder upstream coming off the right (UK drivers side) bank.

You are sooting too fast. Next step is high pressure smoke test. Cutting and cleaning the DPF should be last resort and is very unlikely to be your problem. The DPF is just the receptacle for the soot, you need to identify the source of that soot.

Great that you are regenning well.

If you go back and read my post on page 33 of this thread 28th April there is some history and a fairly comprehensive diagnostics list for sooting too fast, of what to check before considering DPF work.

After you've read that, if you would like to have a call just drop me a PM.

Cheers,





. 2012 L322 4.4 TDV8 AB low mileage - a peach
1986 V8 Defender 90 County ex-Swiss Army - Red everything....

My preferred Independent: Roy Hardy. R & B AUTOS LTD, 20 Brook Road, Wimborne, Dorset, BH21 2BH 07500 866775‬ (Ex LR Chief Technician)

If the differential pressure is still way too high after it's regenerated (and this seems to be what the OP is experiencing from his description) then you have a DPF problem and not a soot problem. 2012 TDV8 Vogue (L322)

Jaygee, I hear you, however I don't agree and I still think the next step is high pressure smoke test. 2012 L322 4.4 TDV8 AB low mileage - a peach
1986 V8 Defender 90 County ex-Swiss Army - Red everything....

My preferred Independent: Roy Hardy. R & B AUTOS LTD, 20 Brook Road, Wimborne, Dorset, BH21 2BH 07500 866775‬ (Ex LR Chief Technician)

I agree with you both. I’d like to get the smoke test done to rule out anything intake side as that seems like a good and sensible thing to do regardless and would be sensible preventative maintenance noting the age and mileage on the car.

I also think that there’s a problem with the pressure being read across the DPF. Having just fitted a brand new genuine LR pressure sensor, I have to assume it’s reading correctly. Therefore, 3.5V when holding 4000rpm is way too high when I should be getting more like 1.5V under heavy load. This points to the need to check the pressure across the DPF to ascertain the actual soot/ash load.

Both these things require someone that knows what they are doing and understands DPFs (whether an LR specialist or not). The best suggestion that I’ve had thus far as to where to take the car for diagnostics is TS Norman, but that’s 1hr45 and 70mil from me in Faringdon (just East of Swindon on A420). Whilst not impossible, it’s going to take me a lot of effort to make that kind of journey in and around work as can’t take time off in the work week for this right now.

Therefore, any help or suggestions for something more local (and accessible) will be greatly appreciated!

Thanks as ever for the help and suggestions! Andy

2010 4.4TDV8 Vogue SE in Santorini Black with Ivory interior
2017 Audi SQ5 3.0 V6T Quattro in Volcano Red
2001 Audi Allroad 2.5 TDI manual with low-range in Highland Green. Currently SORN whilst undergoing some serious restoration!

Last edited by Ajmngn on 20th Sep 2022 12:48pm. Edited 1 time in total

The high pressure reading is my main concern on this. If the pipes were blocked or were leaking it would give a low reading. The only physical way to get a high reading is for DPF to be blocked. I assume it's not reading 3.5v at idle ? 2012 TDV8 Vogue (L322)

I would totally recommend Steve at T&S Norman and say it is worth the trip. He will give you a nice Freelander as a runaround if you request.

They do all my servicing now after being the only place to correctly identify, find and rectify my problem. I was getting DPF full signals and RP due to my car being unable to correctly initiate and complete Regens (I know this isnt the OPs prob but bear with me). Through a careful process of elimination, logic and mechanical nouse, Steve identified that the DOPF was not full, the engine was running too cold. This was due to the Thermostat being damaged by another garage on fitting an inlet manifold.

3 other Garages (MD and LR and indie) failed to analyse this.

Just give him a ring. He may be able to help on the phone.

There's some great info here. I think I am the only person on here to ever replace a DPF and CAT with new after literally taking the engine to pieces chasing this issue. I was £30k and 2 years into it...

FYI we had a brand new LR pressure sensor on there which was duff. It is only a diapragm with a sensor + two pipes. I have heard of another person who had the same problem, and as you are leaning on that I might try replacing it irrespective of testing.

It is also worth remembering you might have more than one problem going on.

I think you have all the pieces of the puzzle. Dolphin's advice is good, his engineer solving that issue was genius.

Good luck



. 2012 L322 4.4 TDV8 AB low mileage - a peach
1986 V8 Defender 90 County ex-Swiss Army - Red everything....

My preferred Independent: Roy Hardy. R & B AUTOS LTD, 20 Brook Road, Wimborne, Dorset, BH21 2BH 07500 866775‬ (Ex LR Chief Technician)

Last edited by Range Rover L322 on 20th Sep 2022 6:51pm. Edited 1 time in total

I have to admit, there’s a little bit of me enjoying this as I love troubleshooting this kind of problem. I also really appreciate the help and advice as it’s really helping crystallise my thinking.

Latest thoughts:
- the high V measured on the DPF pressure is the same with the original sensor as the new one. Not identical but very close. The fact it goes well over the supposed max 1V under load, and by so much, leads me to conclude there must be some kind of blockage in the DPF. Whilst I don’t want to fixate on this one reading, it does seem both logical and likely given the car’s history and the fact my EGR had to be replaced recently as it was all clogged up. Whilst I am sure there are ways to diagnose this, spending the money to have the DPF cut off and flushed seems like a worthwhile expense regardless and as I can rule that out completely as a result and also know that I can monitor soot accumulation with more authority as to the true levels and status of burns/regens.
- I am also thinking the RP at full gas is linked. If the DPF was blocked (hence the high pressure as shown by the high voltage under load) then that now makes sense as to why the car goes into RP. If the back pressure increases too much, the car would think it can’t breathe so it’s completely logical that it goes into RP. It’s obviously not completely blocked or I’d have no exhaust fumes and would be in RP all the time. But the fact it only happens when really pushing the engine makes sense. More reason to push on with DPF flush I think.
- Finally, I don’t doubt the importance of a high pressure test. As soon as I can find someone who does this I’ll get booked in. I’ve already addressed the main culprits (plenum hoses and throttle body connections) but accept that there is much more that can show up with the test.

However, in pursuit of the answer I’m conscious of only changing/testing one thing at a time or I’ll possibly not understand what it was that’s been causing it. Plus, a full DPF is more likely to cause engine damage than an intake leak and I need to keep driving the car in the short term so my head says just do DPF and then re-assess. Thoughts (and prayers) always welcome 🙏 🤣 Andy

2010 4.4TDV8 Vogue SE in Santorini Black with Ivory interior
2017 Audi SQ5 3.0 V6T Quattro in Volcano Red
2001 Audi Allroad 2.5 TDI manual with low-range in Highland Green. Currently SORN whilst undergoing some serious restoration!

It's easy to test if your DPF filter is blocked - the off the pipes at each end and do a pressure test. Mine was 0.2 bar yet showing full so Steve Norman knew it was clear. if full it will be over 15bar or stg like that (not sure of the exact reading)

Dolphinboy is a genius... what a great point.

Andy, I am sure you know a lot of this but just some colour + thoughts:

Your logic is sound

but...

I learned during the course of talking to the original L322 design team that there is an accepted variation in performance in these cars. One are of greater variations is the DPF because the technology was still in its infancy when they started bolting them on to sate emissions Fraggles. So there are institutionally approved bodges, like the Regen Demanded frequency increasing exponentially as you blow throug 20,21,22,23,24,25,26,27 inferred grams of soot.

I have seen 210 litres of cleaning fluid put through a DPF and it made no difference to performance
Noting:
1) That DPF was heavily corroded from the inside.
2) That DPF is still working acceptably....

My point is the solutions are never quite the same. There are always idiosyncrasies, a bit like with young children...

Also there are robust tolerances engineered in to cope with the problems. Again I have never seen conclusive proof a DPF clean (on an L322) has fixed a problem. It has always been a perception. I do, however, feel the same about Terraclean. So that's just me.

I'd genuinely love you to do the DPF clean and it to be the solution.

If you would like a call - just PM me

cheers,

Matt

p.s. Trigger levels for your reference:

19.7g Demands Regen
23.3g Amber Warning On
27.5g Red Warning On
17.46g Amber Warning Off
21.25g Red Warning Off





. 2012 L322 4.4 TDV8 AB low mileage - a peach
1986 V8 Defender 90 County ex-Swiss Army - Red everything....

My preferred Independent: Roy Hardy. R & B AUTOS LTD, 20 Brook Road, Wimborne, Dorset, BH21 2BH 07500 866775‬ (Ex LR Chief Technician)

Last edited by Range Rover L322 on 21st Sep 2022 1:06pm. Edited 1 time in total

The soot load has to be calculated from the pressure differential reading in combination with calculated engine load and the estimate of the ash load. In the OP's case where he states there have been only 95 demanded regens this calculation will therefore be way off ( likley due to someone resetting the DPF in software ) and the only reliable data you should be going on is the actual pressure reading. 2012 TDV8 Vogue (L322)