DPF % recalculating

[Wallyspike Lurker Find all posts View Profile Close Wallyspike]

Correct me if I am wrong but I thought the general consensus about temperature needed to regenerate the (Toyota) DPF was above 500C
However Wikipedia (which of course could be wrong) says this:
"Diesel particulate matter burns when temperatures above 600 degrees Celsius are attained. This temperature can be reduced to somewhere in the range of 350 to 450 degrees Celsius by use of a fuel borne catalyst. The actual temperature of soot burn-out will depend on the chemistry employed."
I think that there is a catalyst in front of our DPF but I don't understand what a "fuel borne" one is? Unless they are talking about adblue which our Euro 5 vehicles don't have.
I am very interested in this manual button theory, will there or wont there be one, and also if there really is another ECU update. If there is at least several of us are now monitoring present behaviour so we should be able to see what the "update" does. You can bet that Toyota dealers wont know!

The catalyst referred to is probably the one called Eolys. This is used in Peugeot’s and Citroen’s and is in a small bladder under the car. It needs replacing every 200,000 km or so. A search for Eolys may be worthwhile.

[Wallyspike Lurker Find all posts View Profile Close Wallyspike]

Correct me if I am wrong but I thought the general consensus about temperature needed to regenerate the (Toyota) DPF was above 500C
However Wikipedia (which of course could be wrong) says this:
"Diesel particulate matter burns when temperatures above 600 degrees Celsius are attained. This temperature can be reduced to somewhere in the range of 350 to 450 degrees Celsius by use of a fuel borne catalyst. The actual temperature of soot burn-out will depend on the chemistry employed."
I think that there is a catalyst in front of our DPF but I don't understand what a "fuel borne" one is? Unless they are talking about adblue which our Euro 5 vehicles don't have.
I am very interested in this manual button theory, will there or wont there be one, and also if there really is another ECU update. If there is at least several of us are now monitoring present behaviour so we should be able to see what the "update" does. You can bet that Toyota dealers wont know!

A search for Eolys may answer the lower temp burning.

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

So here is what I have observed since new 2018 vehicle with latest ECU update.

1. Burn takes 10km city driving
2. I can get the percentage full to increase when in a carpark by revving the engine. I managed to get the percentage full to shift from 8% to 18% and back again
3. Temperature during a burn progressively increases to just under 700 deg.
4, Burn at 100km/h gets to high 600's for temp whereas old version would only go low 500's. It only takes about 20km to complete a burn hwy driving now.
5. Have seen 0% full a number of times already
6. Percentage full is still based on algorithm as explained by service tech but differential sensor are also used to determine burn temp etc.

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

Thanks for posting, have you had a chance to monitor with Techstream yet? as very interested to see how the timing and 5th injector firing has changed. I did email you a link for Techstream version 13 which is meant to be more stable but you may not have had time to try it?

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

To add a little more to the posts about the DPF % recalculating and reducing after going quickly up after a burn I have started logging.
I attach a log of Time, RPM, Soot %, Differential Pressure, DPF temperature and 5th injector status. This although very interesting to me could be a cure for insomnia for others. At least it is only a 10 minute burst with readings taken every second. There are more logs!
I am logging because I have covered a lot of Kms lately and the last three regens have always resulted in a big recalculation, one was 88 down to 44 which is identical to that reported by DaveC on the Fortuner forum. The recalculation happens mostly when starting a fresh journey with a cold engine.
The second reason is that the service manager at my dealership says this does not happen.
Although this log doesn't show it, the % fell to 40 then hovered around 40/42 for a long time before beginning to rise again. I do have logs for this but will spare you from seeing them unless you are as sad as me and actually want to. Next log will hopefully be before, during and after a regen.
[ATTACH]n732041[/ATTACH]

Escaped covid home detention for a long Sunday drive of about 650Kms in my 2018 Prado.
At highway speeds DPF regens occurred at around 160Kms.
When I got home the DPF saturation level was at 90%. I had driven a little over 100Km since the previous highway regen.
The next day driving around town the DPF saturation reading dropped immediately to 58%. The next DPF burn occurred at 347Kms.

Regens occur more often at highway speeds than city speeds. I surmise that the ECU senses which is happening and calibrates the DPF 100% metric to occur at a lower pressure differential when at highway speeds - maybe half that for city/suburban speeds.
In the case above, the day after a good run on the highway, the ECU sensed city speeds and re-calibrated thereby "recalculating" the DPF saturation reading tp nearly half that of the day before.

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

Hi John,

Honestly I would have agreed with you on your above statement however once I had the DPF replaced I was getting +300km between burns at Hwy speeds. I would think that you may have the beginnings of an issue with your DPF. I will have to verify next time I am doing a trip down south.

[kittles Lurker Find all posts View Profile Close kittles]

For what it's worth I have just stumbled on this thread after doing some digging on DPF quirks myself!

I noticed fuel economy slipping in my 2016 so I got a tune + exhaust done while I was there and I noticed the DPF would fill up lightning fast. I left the gold coast (Dreamworld) and drove to Brisbane. A burn started about 8 minutes in to the trip and hadn't finished by the time I got to work. When I left work the burn stopped about 5 minutes after I left and by the time I was home the DPF was 98% again.

I've pulled the tune harness off and the DPF is now filling up slower but the smoke that comes out when it regens is crazy. I keep getting people pulling up next to me to tell me something is wrong with the car! A tune will add fuel load but should make it fill up nearly 5-6 times faster!

I'm taking it in for a service soon so I want to put the hard work on the dealership to work out what the hell is going on.

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

What is the "tune harness" that you pulled off?