DPF and white smoke

[LeadWings Member Find all posts View Profile Close LeadWings]

Analysis of Sulfur-Related White Smoke Emissions from DPF System

• 2015-01-2023

Abstract:

In a Diesel engine with a Diesel particulate filter (DPF) system, high-sulfur fuel ........

I thought the diesel we use in Australia is low sulfur?

[CamJam Senior Member Find all posts View Profile Close CamJam]

Trueblue - there's a reason why my car is in tomorrow having it's DPF replaced after the white smoke... I'm putting it out there that it's not simply to appease a customer... that's not really the Toyota way is it? Can't wait to drive with the new one installed and see how they go.

One odd thing - I used to always get 10.5L/100km, then post the recall this jumped to around 11.5L/100. After they thoroughly checked the car out, they decided that the DPF was cactus. But whatever they did for those many hours they were working on it (I waited), certainly did something - my fuel usage over the past month or so has gone back to 10.7L/100km. So after the replacement tomorrow, then I will certainly keep an eye on the consumption - these faulty white-smoke DPFs might be costing us more than embarrassment and time at the dealership...

[CamJam Senior Member Find all posts View Profile Close CamJam]

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[CamJam Senior Member Find all posts View Profile Close CamJam]

I thought the diesel we use in Australia is low sulfur?

In theory we do. And while I am getting a DPF replacement tomorrow, I thought over the past 5000km's I'd take it to another service station for fuel, which has led to NO white smoke whatsoever. The two I used to go to are both reputable (Caltex Vortex and BP Ultimate), however they were a little dingy and didn't quite look as new or up-spec as some.

I'll continue to go to this new servo (another Caltex, but sadly no rewards points) when I get the new DPF - just in case this 2.8L is really sensitive to the fuel/ sulphur. I know they should all come from the same truck, but hey - it's worked so far in that I haven't seen any white smoke over a period that I would usually have seen three or so decent blows of it...

To anyone else who's got the white smoke - could I suggest another servo (and stick with it for three tanks at least)? It was an idea originally thrown at me by the Toyota mechanic...

[CamJam Senior Member Find all posts View Profile Close CamJam]

Update

So I had the DPF replaced yesterday, and have since done 520km's. So yes, it's early days... but

When I first got the Prado I was getting mid-9's for fuel consumption. Then the white smoke started to occur and it crept into the mid-10's. But I thought it was due to the Bull Bar, Recovery points, Pioneer Backbone rack, UHF aerial and a few other things that would have ruined any aerodynamics it had, and added weight.

However, towards the 30,000km mark the fuel usage (and white smoke) really started to go up - to an average of around 11.8/100km.

At around 20,000km I also started to have a really annoying squeal (almost like brake pads wearing) under load. My air con went on/ off, I floored it, I put it in neutral - nothing was really changing this squeal - it ended up just getting worse, and was almost without fail coming on at the same point on my drive home every day (coasting in an 80km zone). The best description for the sound came from a mate - he thought it was those really really loud cicada's that you sometimes hear camping that constantly chirp.

So the DPF got replaced. My fuel economy is back in the mid-9's. There is no squealing.

I'm not saying the DPF caused the squealing (but I suspect it now) but if anyones got that squeal (there's a seperate thread for it) - then something around the DPF - if not the DPF itself - is causing it. THat's where I'd be looking.

I note on the invoice (free for me, but $1445 was on it) that there was a 'Gasket Turbine' replaced (as well as a Gasket exhaust pipe, DPF and Converter sub-assembly) - perhaps that was it? It'd explain that, if it were the Regen causing the squeal then why my attempts to stop it didn't work. It'd also explain why it came on at the same point on my drive home - it'd always probably be up to temperature by then (it's about 25km into it).

So - with fingers on a lot of wood - I think a new DPF has solved thee problems. White Smoke, fuel economy and the squealing. I'll let you know if any of it comes back.

[CamJam Senior Member Find all posts View Profile Close CamJam]

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[prodoco Junior Member Find all posts View Profile Close prodoco]

Update 2

DPF replaced on Monday this week (30/10/2017), it took approximately 4 hours to finish the replacement job. The new DPF makes the car breathe/fart easier and exhibits better throttle response.

[rpn Junior Member Find all posts View Profile Close rpn]

There is no way that the amount of smoke coming from these is "normal". That just sounds like an easy-out for Toyota, because i think they are going to be flooded with 2.8's suffering this problem. The Hilux i saw was literally leaving a white smokescreen behind him. Sure, it may not be damaging the engine itself, but it has to be embarrassing for the driver and surely not healthy for anyone following closely behind. I'd be driving straight to the dealer and demanding a loaner while they fix/replace the POS DPF.

Many years ago I was at an event where a Austin Champ 4WD had a washer bottle rigged up to squirt diesel into the exhaust manifold of the petrol engine (just for giggles). It produced huge clouds of white smoke, so it sounds like the smoke from the DPF is some sort of fault where too much diesel is used for the burn and maybe doesn't affect the engine at all.

[JohnLynn Senior Member Find all posts View Profile Close JohnLynn]

Yes it does look like injecting diesel into a hot enough exhaust produces white smoke. This is a quote from the Red Arrows display team website about how they generate different coloured smoke:
"The basic vapour colour is white, produced by injecting diesel into the hot exhaust from the jet engine. This reaches temperatures of over 400 degrees centigrade and vaporises immediately. The blue and red colours are made by mixing dye with the diesel. The dye and diesel is stored in a specially-modified pod fitted to each of the aircraft."
So perhaps we could modify our Prados with some dye and make a display worth watching?
@CamJam was your invoice split to show the different costs of parts and labour? I am interested in how much a DPF unit would cost.

[nudgebar Member Find all posts View Profile Close nudgebar]

If a new DPF only cost a couple of hundred ( and i suspect thats all it worth to produce ) then replacing it every 100,000klm or whatever would not be an issue. but since Toyota are charging $3000+ for a new DPF then it does become a ripoff.

its like that with all parts - the production cost is tiny compared to what parts outlets charge , hence the problem.

[CamJam Senior Member Find all posts View Profile Close CamJam]

@CamJam was your invoice split to show the different costs of parts and labour? I am interested in how much a DPF unit would cost.

No, it wasn't. At least, I didn't see it - but the total was $1445. The copy I got to keep (as opposed to the one I had to sign for) has NO CHARGE against it all.

I don't know if it'd cost us $1445 - but that's what I was told would be charged/ sought from Toyota.

One other thing today - for the first time in about 20,000km's I have actually smelt the car after a DPF burn. I hadn't noticed before that this smell was actually missing from my life, until I smelt it again. Seems odd.

[120D4D Avid PP Poster! Find all posts View Profile Close 120D4D]

Knowing OEM pricing I'd say the $1445 was labour and consumables only. No doubt TMC supplied the dealer with all the required parts.

[JohnLynn Senior Member Find all posts View Profile Close JohnLynn]

Yes I agree, as I thought $1445 seemed cheap at Toyota's prices for a unit so as above TMC supplied the unit and the dealer claimed $1445 for fitting it.
I am very interested in what happens to a DPF when it fails, I think we all agree that white smoke is caused by raw and unburnt diesel which suggests that the injected fuel isn't burning in the filter. The autoignition temperature (not flashpoint) for diesel is just over 200C and the temperature of the filter is around 300 in normal use according to my torque pro so why is it not igniting?

[brogers Advanced Member Find all posts View Profile Close brogers]

Yes I agree, as I thought $1445 seemed cheap at Toyota's prices for a unit so as above TMC supplied the unit and the dealer claimed $1445 for fitting it.
I am very interested in what happens to a DPF when it fails, I think we all agree that white smoke is caused by raw and unburnt diesel which suggests that the injected fuel isn't burning in the filter. The autoignition temperature (not flashpoint) for diesel is just over 200C and the temperature of the filter is around 300 in normal use according to my torque pro so why is it not igniting?

Hey JohnLynn, why not ask them for your old DPF and take to it with a hack saw, and have a good look inside...i recon it would be worth a squiz...because something is going wrong in that darn thing that's for sure.

I'm not sure I agree that the white smoke is unburnt diesel, didn't the red arrows say they make white smoke by burning diesel in the hot exhaust. I recon its burning diesel alright, and hence the smoke, but I'm not sure if its burning it properly..ie if teh diesel might be soaking into the DPF and at some stage there's just too much diesel getting burnt...or something like that...who knows. I do know that it's going to be a pain if they don't work properly.

[JohnLynn Senior Member Find all posts View Profile Close JohnLynn]

Yes I would do just that if it were me that had the DPF changed! I am chipping in with comments and questions on this thread as I find the subject very interesting and want to know more. Luckily for me so far my manual GXL hasn't suffered from this issue or had any update, by following the manual burn thread parrot fashion I have been monitoring my exhaust temperature and burn % etc which looks fine.
There is a website dedicated to the colour of diesel smoke called dieselsmoke.com.au It lists black smoke as being caused by "incomplete combustion" blue smoke caused by "burning oil" and says that white smoke is caused "when raw diesel comes through the exhaust completely intact and unburned"
Like you I am not sure that I agree with this either.
In my experience with older engines, pre modern electronics which should limit the amount of fuel injected to the quantity that can be used, black smoke is usually caused by an overload.
Showing my age now I can remember leaning to the side of a tractor engine and pressing the cold start or excess fuel button for a laugh. The tractor would belch black smoke until the governor came back up to speed and released the button.
Blue smoke used to very common on starting a large marine diesel. These had huge boost pressures to get as much power as possible and a consequence was that they were very low compression ratio for a diesel. Our local harbour used to be filled with blue smoke when a couple of boats were cold started at the same time. A Cummins marine engine that I still have uses powerful electric inlet manifold heater elements that help reduce this effect before the engine come up to temperature.
White smoke is the colour that I have no experience with until reading the comments on here. Sorry if I have bored you with tales of how things were when engines had "proper" mechanical injector pumps.