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The great DPF myth

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  • Just towed van for 1.5 hrs on highway and extra urban. DPF accumulation sat on 66 with EGT2 temps in very high 400’s. EGR position on cruise 21percent open.
    without van on cruise I get EGT2 temps mid 300’s and EGR 33% open.
    pretty stoked with the passive hold of DPF percentage. Means it’s not burning its tits off all the time under load on highway like it used too.

    Comment


    • JohnLynn
      JohnLynn commented
      Editing a comment
      To get my head around what you have found, the DPF temperature maintains high 400's when under heavier load ie towing which is enough to at least burn particles as they enter the DPF resulting in no increase in soot %
      How do you think this is achieved, is timing changed or more fuel injected later? is the EGR being less open under load what you normally expect or a result of the update?

    • Spook1205
      Spook1205 commented
      Editing a comment
      Definitely EGR closed more than I expected as my foot wasn’t that hard on throttle. So theoretically less EGR more NOx less particulate. A NOx gas has the ability to burn particulate at a lower temp (like euro cars) and Toyota have done this for years over in Europe.
      Even in 2005 they had DPFs in places like Holland (someone from Holland recently contacted me about their 2005 Toyota Avensis DPF, I couldn’t help them much as vehicle never released here). So they are all this type of regen.
      But yes particulate didn’t increase but didn’t burn down either. Even at 80kms hr still held higher temps.
      As for the tune to get temps up that will take a lot more research for me to find out. The Mrs was reading the scantool info out as I was driving.

  • Here's a log I took the other day, it's my drive home from work. My DPF ratio was 100% as I got to work so I remembered to log my trip home. I started with a DPF ratio of 100% and it worked is way back down to 4%.

    The burn took about 15 minutes with a drive from Melbourne CBD. It's a mix of city traffic and freeway traffic with maximum speeds of about 80km. The burn completed well before I made it into the suburbs. I'll try to catch a burn next time I'm driving around the suburbs, I'm positive it can do it in half the time when its mainly suburban driving.

    Log and chart attached for kicks.

    Attached Files

    Comment


    • Spook1205
      Spook1205 commented
      Editing a comment
      That graph is insanely cool for me.
      It really shows time taken to heat up. Effects of deceleration and lag of 3 to 2

  • And we're smokin again!
    I really thought they nailed it this time but this is embarrassing to drive again. Clouds of smoke,
    In my case this latest update lasted only a short time before doing the same 'ol.
    Surely 4 years is enough time to address a problem...

    Comment


    • Bussa
      Bussa commented
      Editing a comment
      Wow. Didn't expect that. So disappointing.

      Did Toyota replace your DPF, or install the manual burn button, or just update ECU?

      Let us know what Toyota explanation is.

    • bugeye
      bugeye commented
      Editing a comment
      Car's booked in so we'll see. DPF replaced a bit over a year ago, manual button installed but I haven't actually had a need to use it and interested to see how it would self manage.

  • Not that I know, but for those with mechanical knowledge, any chance another computer chip or lose wire or something else up or down the line can be stuffing up bugeye's DPF?

    For a the non mechanical type like me, I find it weird they can't fix it. Which is why I think it may be a combination of things??

    Hopefully they get it right this time around.

    Comment


    • bugeye , its possible your 5th injector is blocked again , which will cause what you describe. Spook thinks they should be cleaned every 20k , cos the DPF cannot clean properly unless the 5th is working properly
      2016 GX , in White

      Comment


      • bugeye
        bugeye commented
        Editing a comment
        I'll certainly make mention of this when it goes in, on it's last legs for me tho.

    • Is it possible to do a regeneration off the button just to clear the dpf or to try it out. I tried pushing mine with the engine running and the park brake on and nothing happened. Is it necessary to have a warning on the dash before it can be operated?? Mine s a manual GX.
      Last edited by davidd; 01-02-2019, 07:45 AM.

      Comment


      • bugeye
        bugeye commented
        Editing a comment
        I've noticed that my dash doesn't do as the pamphlet instructions. What I see is a brief (easy to miss) message (something like DPF regen available) on the dash and I assume this is when you can use. the button.

    • It seems that we all need to be as keen/daft as myself and a couple of others who continually monitor their DPF performance to see what is going on. Obviously this is pretty impractical needing at least a scanguage or torque pro running or even in my case sometimes a laptop with Techstream. Of course this shouldn't be necessary as we expect our modern engines to be reliable.
      I am interested to read above that pressing the regen button had no effect, was the engine at normal running temperature and what do the instructions (if any) say about this new button procedure?
      While I respect Spook's findings about how fast the 5th injector gets dirty my 2015 Prado engine without the update and having covered 35,000 Kms with no catch can or any other mods still appears to be cleaning it's DPF without any problems at all.
      I can understand that a lot of city driving on very short journeys where the DPF doesn't get hot enough for long enough can cause problems and also under heavy loads like towing the filter is getting clogged faster than it can be cleared is an issue but Spook has reported that this seems fixed after the update.
      So just curious to know what sort of use the vehicles had that have ongoing trouble as posted above?

      Comment


      • John this a new software update, that comes with a pamphlet giving instructions for the use of it. It includes a number of warning lights on the dash that my or may not flash according to the software response to dpf blocked or part blocked state. The problem is that the lights are not there. Also a manual operation button that doesn't seem to work on mine , which may or may not be normal.

        Comment


        • If on the highway a lot a dribbling / blocked 5th injector will still regen fine for many many kms. Around town and city / short trips it will compound grief.
          biggest issue I believe is raw diesel stuffing the catalyst, a dribbling/ blocked 5th just makes it harder for fuel to vapourise before getting to catalyst. This is on top of insufficient time to burn. Then it’s all down hill from there.

          so I’ll keep cleaning my 5th every 20k kms

          new update burns hotter, faster and has more boost. All these things are a huge win.
          white smoke is raw fuel in exhaust that has gone through the catalyst and still raw. (Low temps)

          As John saying monitor the DPF so you will ping issues before it’s really bad.
          Defiently EGT2 and % are the two to watch. But no point in monitoring if you don’t learn operating parameters. The pic above Dandin put up shows clearly burn temps of EGT2 so it’s an awesome resource for everyone.

          highway EGT2 needs to be 550deg then crank up to about 680 plus last 30% of burn.
          around town add at least 50 degrees on above figures.

          take home info is if you are not getting 550 deg plus on EGT2 get a DPF clean with the wurth product or similar. Then force a regen and monitor temps. If no good it’s a new one for you. Toyota mechanics will do a lot stringent test than this. But above info every one can use.

          As far as the button I am aware it will only work if car tells you to press it. For that there has to be a blockage.
          Hopefully Bugeye this will be last of your problems.

          Comment


          • Bugeye as for the notification of regeneration on dash. I have a GX. After seeing your post here, I kept watching the dash for a notification. Eventually there was the quick one you saw, boy it is quick. It said Regeneration in progress. I then scrolled through the functions on the steering wheel button, which shows the inst. l/100, the average l/100 etc. It showed a "regeneration in progress " notification which stayed on till the regen was finished, but blanks out all the speedo readings etc, till it goes out again. So I guess if you think a regen is due, scroll the steering wheel button every now and then to check. My regen only went for about 15km as it always has. Apart from this notification it seems nothing has changed as far as the regen process is concerned.
            Cheers.

            Comment


            • bugeye
              bugeye commented
              Editing a comment
              Didn't realise that scrolling through the options gave more info, I'll look into that. During my last smokey regen I took the car for a 100k highway drive, that didn't seem to be enough, the regen is still going today.

          • Bugeye, some time back I had a regen that went on for quite a while. So I just drove it and a week later it finally cut out. one way to try and sort it out would be to put dpf cleaner at about half the maintenance dosage i n a full tank of fuel and come back when the tank is empty. Or get up early one morning and fill tank lightly dosed with dpf cleaner and drive for half a day. Stop for lunch and drive back again. Make it a pleasant drive to somewhere worth stopping so it is a good day out. I've done this myself. Fixed my poor fuel economy problem as well as my lack of power problem. Maybe it 's worth try mate. Nothing to lose and have a good day on the road.
            Cheers.

            Comment


            • Just an update: 5th injector cleaned, no more smokey.
              Toyota advised to actually use the manual regen when possible, which I have.
              Takes all of 3 minutes to complete at the moment and my frustrations have been settled.

              Comment


              • Sounds good 👍 Fingers crossed no more probs.

                Comment


                • At last my Prado has had the update, it had it's final capped service at 38,000 Kms on the very day that I received the letter so the ECU was updated at the same time. Soot was 66% when it went in and 2% when it came out so they must have done something! It has only done short journeys since but here are my observations: 363 Kms before a regen, no recalculation as far as I could tell, this is a surprise to me, it could have been missed? No passive regeneration either even when towing although DPF reached 430C but engine not under much load as 80 Km speed zone. Once 100% reached the DPF temp reached almost 600C and reduced to 56% in 8 Kms before I arrived home and interrupted the burn. Next trip was only a short journey starting with a cold engine, % rose to 58% before the regen restarted when the engine was up to normal temperature. 7Kms later I had reached my destination and the soot had reduce to 8%, the engine had stopped fast idle, (1200 rpm as it is manual) but the DPF temperature was still almost 600C so I left it at normal idle to see what happened. Before the update the exhaust temps would quickly fall at this point but they stayed high and the % continued to drop right down to 0%. The temperatures then began to fall back slowly and I got bored and switched the engine off. So to sum up 363 Kms between regens and a total of 15Km to complete the regen in suburb driving conditions.

                  Comment


                  • Spook1205
                    Spook1205 commented
                    Editing a comment
                    I have noticed the recalc but to think about it it’s not as aggressive.

                  • JohnLynn
                    JohnLynn commented
                    Editing a comment
                    OK thanks, I drove only about 10Km today on first journey, 32% initially then up to 34% followed by decrease to 22% by the time I arrived. I agree this doeasn't seem to be so much but would it have kept decreasing had I not stopped? On the way home it steadily rose again. The FB reading was reset to 1.0 when it left the dealer and has remained on 1.0 after the only regen so far.
                    These things are a mystery to me, why would the ECU recalculate the soot, why cant it just increase more slowly? I don't understand what parameters go into deducing that or the FB either. I think you may have told me the reason or at least your theory about this but I cant remember!
                    Last edited by JohnLynn; 6 days ago.

                  • Spook1205
                    Spook1205 commented
                    Editing a comment
                    Hi John, your observations on soot accumulation is pretty watch what I observe on the tuna.
                    The FB value I never been able to get more info than a small amount of evidence points to if it is under 1 it’s not looking good for the system.
                    On the recalc thing again a theory but makes sense for calculation to be conservative then adjusts if no problem is found and signal from pressure sensor matches the perceived accumulation level by the algorithm of fuel used and vehicle running conditions.
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