Hi Onelnoh.


I took my back to the dealer as a stated in my last post, before grim reaper got a bit precious.


I told them that even if it came up no fault found on the computer, I wanted them to remove the EGR and clean it. They did and found it completely blocked with sticky soot (the EGR cleaner I had used had merely softened the cake into a gunge). The valve was moving only about 2 mm not the 20mm or so the said it should have been moving. They cleaned it up, charged me two hours labour, and the car has run as good as it ever has returning 45 mpg and I seem to be getting most of the 143 hp the engine is supposed to deliver.


I've driven about 1500 miles without any repeat symptoms, so finger crossed, its fixed. Good luck with your car...but I would recommend you look closely at the Exhaust Gas Recirc Valve.


I hope this helps


K

 

Given the amount of miles the car has done; a good clear out of the EGR would be worthwhile anyway and I shall certainly have a butcher's at it.
I have tried no additives as I've heard varying reports on them and I'd like to know the root cause of the problem and not just blow a load of coin treating possible symptoms.
I found a replacement DPF sensor for circa £100 (Mazda would like 300!). Either way, it's a lot for a small piece of plastic. Especially when one isn't sure.
My "communication failure" notice, and the fact that when disconnected; the DPF sensor's absence has no effect on the lights or engine noise, suggest to me that it's a culprit.
The nagging doubt I have, is caused by all the symptoms and lights being the same as before, when a guy at the garage did the reset.
Still, gonna have to take a punt soon, as the limp mode is a drag and it seems the next logical step to try.

Will keep you posted. Cheers,

Phil.

 

Ive got exactly the same problem. Mine also aborts the regen with the wire link ans 2 pedal pumps on the accelerator. Did you sort this in the end? Any help would be greatly appreciated. Thanks in advance, simon

 

I had DPF fproblems changed filter was ok for 200 miles them light came back on had another DPF fitted oil change and oil filter but the light won't go off waiting for it to go into a Mazda garage does anyone know why the light won't go out

 

This blog have some article about DPF topic.
http://www.car-auto-repair.com

 

Carl69,

have the same car and the same problem.


how do You pass the diesel car emissions test now,

without the dpf?

do you maybe know jour smoke level now?

it should be no more then 0.52

whith dpf it is 0.00

 

Hello all,

How I solved this issue:
1. As Dolphin says in this thread; remove the EGR valve and clean it out! (I couldn't get mine off due to a rounded bolt head on the lower side but I could expose the inlet and outlet and give the whole thing a good flush with carb cleaner).
If the EGR valve gets stuck or cannot fully close, any regeneration attempt will abort.
2. Disconnect the Mass Airflow Sensor and run the engine. This will add a P0101 code to your existing P242F. For some reason the latter will not allow itself to be cleared without the former being added. Engine off, reconnect Mass Airflow Sensor.
3. Connect an OBDii reader to the socket under the drivers side dash and with ignition on/engine off use "Forscan" on a laptop to clear the codes.
4. Using same software, perform a regeneration and reset the DPF counter.

If the above steps don't rid you of limp mode for some time, then you probably have a filter which has gone beyond the permitted ash level.
I had, some time before, fitted an aftermarket DPF filter which I presumed substandard, hence the return problem after 4000 miles. In reality, the filter was good but a regen couldn't be completed due to a clogged EGR.

My appreciation to those in the forum whose info helped me to beat this!
Regards,
Onelnoh

 

Onelnoh,
Thank you so much,

with your help I solved my DPF problem completely.

I did not see the Dolphin post, so your instructions directed my in the right way.

So here is my full story with a lot of details, for anyone that it could help. It is really long post I did not intent to write 4 A4 pages, but I did photo document almost everything, and tried to cover everything in detail, as Onelnoh new found information really encourage me that I could do it all by myself, so I wanted to give the info back. And maybe it should be split info 2-3 threads, but it is all here now. All together I spend about a 1,5 month of learning with repairing the car myself, waiting for spare parts, cleaning the DPF, researching the internet and clearing the error codes. Really a hassle, but I also have a second Mazda an RX-8, so I was not pressured to do it quickly.

My car is Mazda 2.0D 2008 GH, the DPF is Mazda original on the car, and was physically cleaned once before at about 200.000km, has now 313.000km.

I did not clean the EGR as you suggested, because I knew I had another problem (physically broken temperature sensor on intercooler I also had an error code P0098 Intake Air Temperature Sensor 2 Circuit High for that. So, I fixed that first, unfortunately this problem meant that at the time not measured air was escaping engine intake at intercooler, the fuel mixture was too rich and caused engine to create more soot than normal, which then caused DPF to clog since I was on a trip on a highway about 400km away from home, which was enough to clog the DPF completely.

When the first stage CEL appeared on the dash board steady “DPF”, it is a warning light to make regeneration I did not stop to make a forced regeneration, which I know now I should have done, maybe all would be fine. I drove like that for another maybe 150km then second stage CEL blinking “DPF” appeared this is a warning light that the DPF if over 100% -200% full (see attached pics) and you should go to a Mazda dealer for DPF replacement.

This was the biggest problem for me because the, as I call it, second stage CEL cannot be cleared with standard OBDII software I was used to, I use the really popular Torque for android successfully for a number of years now. It does read the errors, and can try to clear them, but they come back right away.

So as Onelnoh and Dolphin said I used Forscan, but at first could not connect to my Bluetooth or cable adapters I tried with 7 different types, some would connect Forscan to the adapter, some would do nothing, but none would connect from the adapter to the car I tried with android and with windows. So, the first problem was in finding the right adapter than communicate with car as Forscan requires it, on their page and forum they explain this in detail, and say that the new ELM327 mini and other copies that cost from 5$, are 80$ all “fake”. They are great cheap way to connect to your car with your phone fast and easy, but to connect Forscan you need real ELM327 chip or modified, since it is 10 years old now. So, if buying search for Forscan compatible preferably with MS / HS CAN switch, Bluetooth or cable it does not matter.

I ended up connecting my win10 laptop to a 10-year-old EM327 Bluetooth OBDII scanner.

And same as on Torque I could not permanently clear the codes, they would come back, but with the forscan you have direct access to car modules, 7 in total I think, one of them is for DPF, and there you can delete the learned stored values for DPF soot accumulation. This did it for me. Cleared all 4 codes that Forscan read that were connected with DPF problems.

In the mean time I took my DPF from the car and cleaned it physically, it is quite labour intensive, and hard to get to in places, a bit of trim to take down, you have 4 electrical sensors to disconnect (see attached pics), 2 temperature and 2 Oxygen, and 2 hoses for differential pressure sensor (can also be a problem for some people), a few very big bolts, and a few rusted bolts I had to hack off with a grinder, the DPF itself is quite long and heavy to handle, especially tricky when filled with 5L of dangerous liquid, very alkaline solution industrial detergent, that partly dissolves the soot.



About DPF cleaning services:

For Your information the DPF cleaning machines are the way to go if you are not the DIY guy, but if you were not, you probably would not find this post anyway. The ones that clean with heated pressurized water/cleaning solution clean very well, they clean with 16bar pressure in reverse direction, the soot comes out from the pressure and the cleaning solution and the heat break it down, after the cleaning the dry it out with air.

The other popular procedure is to “bake” the filter in an oven for a few hours or days if needed.

The soot burns at temperatures over 600°C, it turns form black soot to white ash that is smaller and can pass through the small holes that otherwise trap the soot in the DPF and the ash is not as harmful to humans. The same thing happens with regular regeneration when the car injects extra fuel in exhaust stroke witch than burns in your exhaust and raise the temperature to 600°C.

The biggest plus from professional services is that, if you find the right one, the do measure the before and after, so you know how clogged your DPF was and how clean it is after, the do guarantee that I would be up to 95% clean afterwards.

The problem with both of these procedures, other than the cost a lot, is that you are required to take all the sensors from the DPF, which could be otherwise destroyed by the water bending them with 16bar pressure, the chemicals etching them, or just burn electrical cables a connector by the heat in an oven. To get them off could be very tricky, a tried to take mine of and could not take neither one of the 4 without using excessive force or special tools (torches or induction heaters are often used), so I decided to keep them on. All mine sensors bolt heads were damaged by someone who tried to take them off before. The 4 of them cost a lot to replace, did not check exactly but about 100€ each, so maybe as much as the whole DPF itself new original once could be about 1000€ or more, on eBay you can find replacement ones for 300€. If you decide buy a new DPF you again have to remove and refit the sensors, so try to take them of beforehand.

I would not recommend to buy new DPF filter because you can regenerate your old one for about 150€, or for free if you do it yourself, very well almost all the time, if it is not bend, broken or melted on the inside.

I tried to clean mine by blowing compressed air (didn’t do much), water form a garden hose (didn’t do much), tried to burn it with a heat gun and a blow torch (didn’t do much). All these solutions could work with cleaning DPF but the problem with Mazda6 one in particular is that you cannot get to the DPF directly. On one side there is a bend in the pipe and then there is the CAT in front of the DPF, they are in the same enclosure, and one temperature sensor, and on the other side there is a 1m long exhaust pipe and 2 sensors in the way.

The heat gun at 550°C and blow torch would do it in theory because propane/butane flames bur at 1800°C that is more than enough to burn the soot, but my hand held one my was way too weak, they are both about 2kw of heat power, on the 1m far pipe end after a few minutes of heating I managed to get the temp in the exhaust to about 100°C, but already 10-20cm away it was rapidly falling down, 1m away the dpf was still at ambient temperature of 18°C. If you try to from the other side you have the CAT in the way witch also rapidly cools down the flames and the temp sensor that could get burned. Also, since your cat is clogged, you cannot force the flames to go to the other side through the clogged DPF, they just come back out the same way they came in. If you have a much stronger torch you can try, but be careful not to melt the DPF material, I have seen some YT videos with melted DPFs.

I tried with a small pressure washer that did do some cleaning, but again the obstructions do not let you get to the dpf directly. The pressure washer is so powerful that I ended up breaking of some of my CAT when washing it from that side (see attached pics). The ceramic CAT is very brittle, the DPF was not damaged by pressure washer at all.

Most of the job I thing was done with chemicals, I tried putting a bit of soot from the exhaust in a glass an watch it literally melt the soot, after 2 days testing it did not melt it totally but it attacks the surface right away and then if I stir and shake it leaves black streaks behind, that why I knew I can not only leave it sit and soak but have to move it, as they do on the professional machines witch pump the solution through the dpf. I tried the same piece of soot soaking in water nothing happens at all, so the water is only for mechanically removing the soot, after dissolved.

I also researched internet for what professional DPF cleaners use in their machines. Ended up trying Dimer from Atas, Italy, 2L package 2 component solution alkali base and detergent with active surfactants. DIMER | Atas - Detergents for the car and household field . The alkali-based solutions are used to clean industrial boilers of soot. My father used to work for a big national company producing detergents so he gave me the info. Used only 1L diluted with 4 litres water. Blocked all holes on the DPF, and filled it to top, soaked DPF from the inside, for 2-3 days, then and then poured it out thought a filter to catch all the soot particles, and then filled it back in and repeated 5-6 times. Rinsed it with water, filled it full of water many times, rinsed it with pressure washer, forced water through every possible hole and direction, used the differential pressure holes. Actually when the DPF was filled with the cleaning solution I repeatedly forced compressed air thought the differential pressure hole that is behind the DPF so the pressure forced the solution thought the DPF I am sure this helped a lot because there was pressure in the beginning of the cleaning process, and when removing the pressure the solution would spit back out thought the same hole, showing the chamber behind DPF was pressurized and the solution could not force itself through the clogged DPF medium. Also injecting pressurized air through small areas with detergent resulted in the solution bubbling really much, ant he bubbles carried out the soot on its surface. At the beginning the bubbles where black, near the end the bubbles where clean white.

I also tried to do the MAF sensor trick as you suggested with Torque, but unfortunately it did not work for me. When I disconnected my MDF sensor I did not get the expected P0101 code, but two different codes P0102 – Mass or Volume Air Flow Circuit LOW input, and P0113 – Intake Air temperature circuit high input (see attached pics). When reset the DPF codes stayed.

Unfortunately, some error codes cause the car to go in different safe modes, I have a list codes the engine (see attached pics), and then when the car is in safe modes the ECU does not allow automatic DPF regeneration. THIS IS REALLY REALLY STUPID AND UNFAIR FROM MAZDA, because any time I had trouble with dpf clogging it was not the DPF itself but some other error that throws car in safe mode, and if you are not near a Mazda dealer and do not go to them right away you end up with a clogged DPF, which is often a bigger and more expensive problem than the one that caused it.


I also tried driving the car without the DPF, to see if the differential pressure sensor would maybe “see” that there is no blockage now, but it did not help to clear the codes.

The car is quite loud when driven without the CAT and DPF, but not very very loud as petrol cars are, and you can hear the turbo very well. With the the DPF but without the 2m pipe and the back muffler it is much quieter. And just without the back muffler the difference is very subtle, barely noticeable if you do not pay attention. But there is some more deep bass, I like it I removed and fit a larger muffler tip, it and drive it like that for 2 years.

After all cleaning was complete and put back together I turned on the car it spit out the rest of the sludge that the cleaning solution melted. Then drove the car on motorway for half an hour, it did an automatic regeneration right away, I monitor the temperatures by OBD Torque on my mobile phone, to see when the regeneration starts and finishes, you can also monitor the fuel consumption, but that is harder to spot, and not so precise. Then I did one more forced regeneration one with Forscan, just to try it, but there was no smoke coming from the exhaust at all, so I stopped it after about 10min. The car drives great I have all the power as before.

All the sensors survived the alkaline bath for now, all show correct values I did not get any new error codes.

All this time I was thinking about cutting/removing the DPF completely, that’s why asked Carl69 who that just that in this thread, how he passes the emission test now? But after successfully regenerating the DPF I decided I would not do it, because of the emission test. I am from Croatia and some new stringer laws for diesels are in plan for year 2019. But after all that trouble I could not keep myself from drilling a few holes to make it easier for the car to breathe, and get the soot out, because the DPF has 300.000km and it is probably a bit permanently clogged, and every service station said it is time to buy a new one, and for some soot that maybe fell out from the DPF but could not get out through the CAT when washing, and for the differential sensor to sense less pressure and regenerate the DPF less often, to get less oil dilution because now I had about 4 litres of diesel to 4 litres of oil after 10.000kn, that’s about how much it is when it gets to the “X” mark on the oil stick, and I do not think it is good to drive with that much diesel instead of motor oil in the engine, and do not want to change the oil every few thousand km. Part of the increased oil dilution could be to worn injectors. So, I drilled one 16mm hole through the whole DPF (not the CAT) and 2 16mm holes through almost all of the DPF. I would maybe drill more small holes and less deep, or just open the back few mm on the dpf to let the soot fall out to resemble the look more like a CAT. But that just is not possible through a meter-long pipe (see attached pics) without cutting the DPF open with a grinder taking the heat shield and removing the sensors, and then you have to weld it back and on emission test they can see that and not let you pass. This cannot be seen. There is very very little black smoke now visible in the exhaust when you press the gas to the floor and to the max revs (the same as they check it on MOT) when stationary, no smoke at any revs when not driving or when driving. So, there will be some smoke level detected on MOT, hopefully not enough to make me not pass MOT. I did have 0.00m-1 results on last MOT, that means no smoke level at all, the car default is 0.52m-1 and our legislation allows 1.5m-1 right now, but that will probably change. The MOT results after drilling are 0.12m-1 average (three tests 0,13 0,14 0,10), so way under the legal limit.

The DPF does not trap 100% of the particles anyway, so maybe this is just the right amount that I have now.

I do not know the exact measures of the dpf from inside, if someone has a picture it would help, but I measured it from the outside, and took pictures with my phone and an endoscope camera, and try to calculate (see attached pic). Total surface area of the 3 wholes is 6cm2 and total PDF area is about 154cm2 so that equals to only 4% DPF drilled, and just 1 hole is really toughly drilled.



Thanks to Onelnoh and Dolphin once again.

If anyone have any questions/need more pictures feel free to ask.


https://euroesi.mazda.co.jp/esicont/...6f1805100.html

 

more pics: