Engine: D5: Soot Filter driving me crazy...HELP !

[Nick44]

Originally Posted by RoyMacDonald

Hi Bill

It's going to be interesting to see how the stop/start system being fitted to new cars is going to affect the DPF's


Roy

Indeed it is.

[RoyMacDonald]

Originally Posted by Nick44

Indeed it is.

Thinking about it, Volvo start going plug in electric hybrid next year so it's unlikely to be a problem with them.

[Bill_56]

Originally Posted by RoyMacDonald

Hi Bill

I may be wrong but my understanding of the the electronic throttle in the EGR is to balance or cut off the EGR. Nothing to do with air intake. The D5 is still has the usual diesel injection system and that is nothing to do with the EGR. My D5 dosn't have a DPF but it does have the EGR. The electronic throttle is just a butterfly flap and an electric motor. More like bad luck and a bit too much carbon probably. I always use Shell V+ diesel in the hope it keeps the system a bit cleaner from carbon deposits.

Are you sure we are talking about the same throttle valve?

It was suggested (by Clan) that one purpose of the one I'm talking about might be to block the air supply when the ignition's turned off, thereby stopping an engine that was self-fuelling from its own oil. Does that not imply it is an air-intake throttle? How could the EGR valve on your Euro III engine accomplish that effect?

Thanks in advance,

Bill

[RoyMacDonald]

Originally Posted by Bill_56

Are you sure we are talking about the same throttle valve?

It was suggested (by Clan) that one purpose of the one I'm talking about might be to block the air supply when the ignition's turned off, thereby stopping an engine that was self-fuelling from its own oil. Does that not imply it is an air-intake throttle? How could the EGR valve on your Euro III engine accomplish that effect?

Thanks in advance,

Bill

The air mixes with the fuel via the injection system, separate from the EGR, when the exhaust gases are being recirculated they also contain air. The purpose of the EGR is to reduce Nox. The valve appears to be for helping the EGR system get going and to shut it off to increase exhaust gas temperature during active regeneration.

[Bill_56]

Originally Posted by RoyMacDonald

The air mixes with the fuel via the injection system, separate from the EGR, when the exhaust gases are being recirculated they also contain air. The purpose of the EGR is to reduce Nox. The valve appears to be for helping the EGR system get going and to shut it off to increase exhaust gas temperature during active regeneration.

I'm not sure we've reached agreement on the purpose of the throttle, or whether the part I've just replaced was fitted prior to Euro IV. But no matter, we seem to at least to be in agreement that a throttle forms part of the DPF regeneration mechanism, and therefor will be subjected to additional wear & tear in a car that's fitted with a DPF. And, indeed, the failures discussed so on these forums seem to mainly (or only?) affect DPF equipped cars. Which, really, was my point.

Going back to that description of the Jaguar regeneration, I see it's not just one but two post-injection squirts during regeneration. For a car that always regenerates at the first attempt it's probably insignificant, but for a car that takes several attempts before regeneration suceeds, it must add up to a significant lifetime burden on the injectors too, assuming jag owners are like Volvo owners, expecting a car to last for hundreds of thousands of miles.

Even the glow plugs see extra action during regeneration, so the same would apply there too.

I wonder if all these various parts have been uprated to account for the extra work they'll have over their lifetimes? It would be interesting to know if these, or any other such 'DPF related' components, are suffering reduced life-exectancy on DPF-equipped Jaguars, and whether Volvos are any different.

In the case of such components, it is unlikely that even tech-savie enthusiast owners, let alone school Mums (sorry for stereotyping), would twig that the DPF was a contributing cause of premature failures, which might well be leading to an under-estimate of the impact DPFs have on overall reliability.

[pont]

As far as DPF is concerned, its a no brainer that the ecomentalists have forced this on car manufacturers before the technology is sorted.
Its also clear that as the ordinary motorists work out that DPF is bad news, then these cars will be dropping value pretty darn fast and become unpopular. I do not want a DPF, I will not buy a car with one. Others will feel the same.
Unless you spend the majority of your time on motorways, and never plan to tour the French countryside or similar, do yourself a favour and do not buy a car with DPF.
What is the v70 coming to? I love mine, Pre DPF , but what with electric handbrakes and DPFs, I shall not be hurrying to the dealer to trade in.
Rant over

[111]

Sorry if this has been covered somewhere but there was to many posts to read, I know that people with Vectra CDTi estates and Singums are getting the regen and PDF written out of the ECU software as well as removing the CAT without any problems & thus getting rid of the overfueling and smoke issues & obviously the dealer visits,
http://www.vectra-c.com/forum/showth...iculate+filter
Hope this helps someone

[Bill_56]

Originally Posted by pont

Unless you spend the majority of your time on motorways, and never plan to tour the French countryside or similar, do yourself a favour and do not buy a car with DPF.

Even if you do spend the majority of time on motorways, it would be wise to only use motorways that are always clear of traffic jams.

I say that because another point seemingly cleared up in that Jaguar description (see link&disclaimer below) is that, as I understand, so called 'passive regeneration' only converts 'a portion' of particulates, and that the car will ALWAYS undergo active regeneration after some threshold mileage is reached. That appears to happen regardless of whether the backpressure sensors say it's needed, and so active regeneration may still be initiated, hundreds of miles into a fast motorway journey on a hot summer's day.

Here's the jaguar link again, for anybody who missed it earlier in the thread, it makes excellent reading...

http://www.jaguarforum.co.uk/viewtopic.php?f=22&t=25040

...Conscience dictates that I add, the information in that link may look convincing, but I cannot verify its authenticity. Remember this is the internet and all sorts of deceptions are possible. Judge it for yourself. And even so, we can't assume that Volvo do the same, though I'd be surprised if there were much scope for the different manufacturers do do things differently.

[RoyMacDonald]

Hi Bill

Why don't you just get your DPF removed as you don't like it? It's only a legal requirement for Volvo to fit one from the factory. There is no legal requirement for you to keep it though.


From Yahoo cars re my non DPF engine.
It was also the first diesel engine to feature electronically controlled Exhaust Gas Recirculation, which reduces harmful nitrous oxide emissions, and is also fitted with a Variable Nozzle Turbine which claims to extract boost pressure even at low revs

From pistonheads.com
The EGR valve has a well defined function in modern common rail TDs. It's malfunction can, given time, cause a turbo to fail. TD engines, particularly **** (Thin Wall Alloy Technology) ones, rely on the introduction of NOx as a cooling gas to cut emissions. Failure to do so will increase both the temperature of the oil and the exhaust gasses. This, in turn, may well hasten the demise of the turbo.
I am dubious of the benefits of NO or N2 as a cooling means as they are coming from the exhaust side and being fed in to the inlet side

From Simon at FRF re EGR
hi mate

have you seen the inside of it yourself yet? i have seen a few of these when they are coked up, and they are generally well beyond cleaning. they coke up worse than other parts i have seen by far, as it go's extremely hard. may be worth a go, but its a long shot unfortunately.

Simon

All D5's have electronically controlled EGR's.

Volvo use the word throttle in reference to throttling the exhaust gases. Nothing to do with the throttle that controls air in a carburettor.

Some stuff on EGR's here http://www.answers.com/topic/exhaust-gas-recirculation


The DPF cars on the XC90 forum are doing hundreds of thousands of miles without it being an issue. The use of the injection system for the DPF is tiny compared to normal injection use. The EGR system carbonation failure is well known though on non DPF cars but dosn't seem to be quite as much of an issue on DPF cars.

Hope this helps.

Roy

[RoyMacDonald]

I should correct a mistake I made in an earlier post where I said the EGR gases contained air. They don't.

From http://www.asashop.org/autoinc/dec97/egr.htm

EGR/PCM strategy
GM's Code 32 has been around a long time and can be caused by a variety of reasons. Every three to five years, the PCM strategy on this code changes. Make sure you review the proper flow chart any time you work on one on these. The strategy is slightly different depending on which engine, transmission, body type or year the car is. The most common strategy entails the PCM looking for fuel integrator counts to decrease momentarily when the EGR is commanded open. Why? There is no oxygen in the inert EGR gas, so the integrator subtracts fuel to compensate. For this to happen you must have a good working oxygen (O2) sensor. O2 sensor checks are usually not in the Code 32 flow chart, so be aware. Newer models and other makes look for a change in manifold absolute pressure (MAP) when EGR is flowing, which is a more reliable method.