DPF and white smoke

[sia535 Lurker Find all posts View Profile Close sia535]

Unless you are as obsessed with the issue as much as me and/or have the advantage of torque pro on an android head unit or scan gauge I cant see how you can know when a regen is taking place during normal driving. It is different if you are stationary but even then an auto only increases tick over to 900 not the 1200 rpm on a manual. I presume this is because you would waste so much energy heating the transmission oil if you sat at the lights in drive?
My feelings are that our DPFs don't do any passive regeneration just a forced one, in my case usually every 300 but I have seen 400 Km. I could easily be wrong !!!
Anyway there is an interesting thread on the Fortuner forum called "the great DPF myth" where someone with a lot more knowledge than me has confirmed my observation that since the ECU reprogram the % increases quickly then can fall back without the DPF temperature appearing to increase. I have noticed this twice now and began to question my findings so I would be very keen to hear of other's experience. Is this different behaviour where the ECU re-evaluates the supposed % clogging half way through a cycle?

You are absolutely right, I can't tell if it is doing a Re-gen while the car is moving, only time I can tell is when the car stops and the Rev counter increases to 900 rpm instead of the normal 680-700 or the transmission does some very rough down shifts while on the move.

My understanding is that if you are on the highway long enough the heat from the combustion will clean the DPF so it doesn't need a Re-gen to happen. If not because of the white smoke that once came out of the exhaust, I didn't even care to monitor the Re-gen process. There's so much about this DPF that is not explained properly by Toyota and its dealers, we are just kept in the darkness, it's quite annoying to worry about if your 6 month old car will breakdown in the middle of nowhere since I'm doing a round trip from Sydney to Uluru in April!!

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

Yes there is a lot that is not made public about how this DPF works. The consensus on the Fortuner forum seems to be that it doesn't ever do passive regens. I tend to believe this as the temperature apparently should reach over 500C and during normal driving mine is between 275-350C which I assume is way too cool to burn the soot.
Wouldn't it be nice to know why our engine needs an active regen approximately every 300 KMs yet a Jeep manages 1500 KMs and of course why it appears to never regenerate passively? As I have pointed out before my family in the UK have an Audi A3 and VW Golf diesels neither have ever appeared to be running a forced regen even after very high mileage.
I can understand you being slightly apprehensive undertaking a long trip but if you do go to the trouble of monitoring temperature and perceived clogging % you would at least have advanced warning if anything was starting to fail.
My continued interest in this issue is driven by my geekyness, I want to understand how the system works, and despite all my posts commenting on the DPF my vehicle seems to be performing exactly as it was designed, or at least as far as I can tell.

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

I have just posted this on the Fortuner forum as a couple of owners have noticed a decrease in % full after the ECU update which most of you had some time ago, remember that my car was only recently modified as it was laid up for 7 months:

I have been running about with Torque pro showing on my screen, even getting a passenger to take pictures so that I do not have to rely on my memory.
Today we set off with a cold engine and the % reading of 42, this was only about 50Kms after the previous regen. The % increased to 44 then decreased to 42 again and continued to decrease in the usual steps of 2 (I think this could be changed with a different equation) The engine temperature was only 70 when this began and the exhaust temperature did not exceed 350 throughout the journey which consisted of about 20 Km of 80 speed limit followed by about 5 Km of city stop/start driving. When we arrived the % had decreased to 16, the car was left while we were shopping and on the return trip the % increased in steps of 2 at the usual rate, ie not as quickly as it had for the first 50 Km after the burn or as fast as the decrease.
I wish that I had monitored this as closely before the ECU update as I have afterwards but nevertheless I am fairly confident that this decrease in % did not happen before the mod.

[Micko2005 Junior Member Find all posts View Profile Close Micko2005]

Mine is a 2016 GXL Diesel auto, just clicked over 20,000ks. Couple of weeks ago when accelerating from a start on a hill, a big cloud of black smoke came out from the exhaust. I had noticed a small amount previously the week before. Anyway it was due for a service this week so I asked them to check it out. This combined with fuel economy of 11.5 / 100 k (stock standard no mods) for combined city highway driving had me thinking for some time something was wrong. Anyway Toyota advised DPF is stuffed and the 5th injector was clogged. So they did a manual burn cleaned the 5th injector and a new DPF has been ordered. So hopefully when the new DPF is installed the fuel economy will improve.

[LeadWings Member Find all posts View Profile Close LeadWings]

I have had no DPF issues, but have had a friend who had his 7,000 km Prado go into limp home mode. We do some pretty remote trips, so I wanted to be able to see what is going on and be able to force a burn and reset codes in case it goes to pot out back.

Some clever chaps cracked the monitoring codes and force a regen codes - see the "Forcing a DPF regen with OBD tools" thread.

With a $20 dongle from ebay, an iphone app and the info from the forums I am now able to monitor the DPF %, temperatures and force a burn if necessary. It was all relatively simple. I have documented all this on the "Forcing a DPF regen with OBD tools" thread, starting on page 4. http://www.pradopoint.com.au/showthr...BD-tools/page4

Figure it is cheap insurance in case I have issue when bush and need to get the vehicle working till I can get to a dealer.

[tonykarter15 Junior Member Find all posts View Profile Close tonykarter15]

I am seriously concerned with what I have read through this thread. I have a 2013 3.0L Diesel without the DPF and was thinking about updating to a new prado this year. I am starting to think that this could be a massive mistake going from a reliable 3.0L without injector issues into an unsolved issue with the DPF & burns etc.......

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

I have had no DPF issues, but have had a friend who had his 7,000 km Prado go into limp home mode. .

That actually makes me more comfortable. I'd been told by Toyota that there was no limp home mode for a DPF fail anymore - there couldn't be under the new regulations (also the case with AdBlue in the Everest if you ever run out). I'd love to know the real answer.

In Limp Home, I can at least get my family back to civilisation - even if it is at 30km/h and takes ten hours. We'd get there, we'd have air con (guess) and can get in range at least for the phone. But if we're stuck, out of range, and have no car then that's a whole different ball game.

[nudgebar Member Find all posts View Profile Close nudgebar]

I wish they would confirm that , as far as i know DPF blockage at 140% causes limp home mode. if the DPF was that badly blocked and not passing any exhaust i would imagine the engine would soon stop running.

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

I wish they would confirm that , as far as i know DPF blockage at 140% causes limp home mode. if the DPF was that badly blocked and not passing any exhaust i would imagine the engine would soon stop running.

I'll ask again next time it goes in. The reason wasn't that it blocked all exhaust - it was because a non-functioning/ blocked DPF didn't meet EURO5 requirements and to meet it, they took off the limp home for a DPF issue! I was flabbergasted, but then Ford and VW have both confirmed that if the car runs out of AdBlue - even though it can operate perfectly without it - the car will not start as it's no longer compliant.

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

I'll ask again next time it goes in. The reason wasn't that it blocked all exhaust - it was because a non-functioning/ blocked DPF didn't meet EURO5 requirements and to meet it, they took off the limp home for a DPF issue! I was flabbergasted, but then Ford and VW have both confirmed that if the car runs out of AdBlue - even though it can operate perfectly without it - the car will not start as it's no longer compliant.

That's pretty standard mate, I know our Kenworths out west that were running it would continute to run if they ran out of Adblue, but as soon as you turned them off they'd not start again. (bit of a pain in the ass if you're stuck in the middle of nowhere mind you). In saying all that, the adblue tank is tiny and it'd be pretty trivial to carry enough to get you out of trouble from most places.

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

I am sure you will put me right if I have got this wrong but Adblue is to stop nitrogen oxides in the exhaust and nothing to do with the DPF which is for filtering soot and tiny particles.
AFAIK Australian vehicles only have to conform to Euro 5 at present, the Adblue is necessary to conform to Euro 6 so not presently required but I think I have read that the wiring is already in our Prados.
Perhaps I worry too much about the DPF issue as I regularly monitor the soot %, DPF differential pressure and temperature and feel I would have very advanced warning if things were not working as they should.
Whether or not everyone should buy a cheap BT adapter and look at an android device to check is another matter.

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

I am sure you will put me right if I have got this wrong but Adblue is to stop nitrogen oxides in the exhaust and nothing to do with the DPF which is for filtering soot and tiny particles.
AFAIK Australian vehicles only have to conform to Euro 5 at present, the Adblue is necessary to conform to Euro 6 so not presently required but I think I have read that the wiring is already in our Prados.
Perhaps I worry too much about the DPF issue as I regularly monitor the soot %, DPF differential pressure and temperature and feel I would have very advanced warning if things were not working as they should.
Whether or not everyone should buy a cheap BT adapter and look at an android device to check is another matter.

True - it's necessary for Euro6 compliance (unless you have some magical fantastic DPF and another piece of tech - it's not written in "you must have xyz fitted" but rather you have to meet emissions which, at this stage, are mainly met through DPF/ EGR/ AdBlue for Euro6) and we're at Euro5 at the moment. I just think a limp home mode is not only more convenient, but far safer should it fail. It's not as if someone will think "Nah, can't spend money on getting the DPF fixed or paying $10 for AdBlue - I'll just trot around at 30km/h"...

EDIT: And yep - has nothing to do with the DPF. The course of history generally had the DPF first, then the AdBlue as requirements got tighter.

[tonykarter15 Junior Member Find all posts View Profile Close tonykarter15]

It makes me wonder what effect a snorkel has in relation to the exhaust issues. A snorkel would force more fresh air into the engine, makes it run richer and whether this would have either a positive or negative effect on the DPF.

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

It makes me wonder what effect a snorkel has in relation to the exhaust issues. A snorkel would force more fresh air into the engine, makes it run richer and whether this would have either a positive or negative effect on the DPF.

I've got a snorkel, I doubt it makes a difference. The reason I say that is that this 'ram air' effect is a bit of a furphy going by physics. The airflow coming in has to do about a 130 degree turn to go down the pipe. So it's lost its momentum. It then bends 90 degrees at least three times (into side flank, along side flank, then again into the engine bay). It then turns 90 degrees upwards and hits a paper filter AND a metal plate that distributes the air more evenly in the Prado. It then makes its way into the pipe heading off to the engine. That's a lot of twists, bends, plates and turns that kill any 'ram air' effect. The air at the top of the snorkel will follow the path of least resistance - once that airflow is clogged up from all this turning and twisting it will create a relatively sedate bit of air at the intake and only allow in what it needs in order to feed the engine (call it akin to the Boundary layer effect), it will simply go around the head. So it's no better or worse than the standard air intake (except it's sealed and higher to prevent water ingress). I think the engine just gets whatever it needs.

It's like the 'it's higher so the air is cleaner' thing. My view is that if you're first in convoy or on your own, then that won't matter - you get clean air. If you're in car number 2 or more, then chances are you are keeping a good distance of around 100m or more behind the car in front - and so all that dust from them will, by the time you get to it, come up past snorkel level anyway... I've done a lot of dusty driving solo and in convoy and I haven't yet seen a benefit of it (other than its intended purpose - the water crossings).

[LeadWings Member Find all posts View Profile Close LeadWings]

It makes me wonder what effect a snorkel has in relation to the exhaust issues. A snorkel would force more fresh air into the engine, makes it run richer and whether this would have either a positive or negative effect on the DPF.

With the modern sophistication in the engines, I think it would compensate - the sensors are measuring air mass flow, temperature etc in the intake, engine conditions such as RPM etc and using it to calculate density etc and basing fuel injection etc on that so would be compensating. And as CamJam says, with all the bends etc I'm not sure it would increase the feed pressure.