[mart4856]

That's the 'Intake air temperature (IAT) Sensor No. 2'

Thanks for clearing that up. I had my doubts that it was a Lambda/O2 sensor as it had no visible holes on it. Is there an upstream O2 sensor on this engine and if so, do you know where it is located?

 

[mart4856]

I removed and cleaned this sensor from the inlet manifold of the 1.5D engine. It’s directly beneath the silver horizontal pipe that runs from the EGR to the inlet manifold. It was filthy and covered in mixture of oil and soot. Is this the upstream Lambda/O2 sensor? What issues could be caused by it being so dirty?

 

[mart4856]

Bonjour,
j'ai une mazda 2 1.5 skyactiv-d. j'avais aussi des régénérations tous les 120-130km.j'ai nettoyé le collecteur d'admission et désactivé la vanne EGR électroniquement. société br performance à Paris.
maintenant la voiture fonctionne beaucoup mieux, l'huile reste propre, la voiture consomme moins et les régénérations se font tous les 400-450km. désolé je ne parle pas bien l'anglais.

Good morning,
I have a mazda 2 1.5 skyactiv-d. I also had regenerations every 120-130km. I cleaned the intake manifold and electronically disabled the EGR valve. br performance company in Paris.
now the car runs much better, the oil stays clean, the car consumes less fuel and regenerations are done every 400-450km. sorry i don't speak english well.

pour Les Anglais.....

 

[mart4856]

My DPF regen history:

View attachment 291486

Each block of points as highlighted by colour is continuous data; on occasion I didn't make a record for a short period for whatever reason (so after the first block of blue points the regen count will be off by some amount that I haven't worked out). I bought the car in March 2022 with around 34,605 miles at which point it had done 212 regenerations. Now it's on 73,551 miles with 628 regens (I have a long commute of 50+ miles each way including 35 miles of motorway!). I've never had any warning lights on the dash related to DPF issues nor any DTCs reported. The oil dilution as read by Forscan has been 0.0 g the entire time. The DPF differential pressure has always dropped to 0.0 or 'error' kPa at idle after every regen, which makes me think the DPF has no issues clearing itself (I assume the 'error' is due to the pressure difference being too low to be detected).

See comparison with MPG over a similar time period:

View attachment 291487

It's kinda frustrating that the car always over-estimates the MPG by anywhere from 15 - 22%!

On the two occasions that I've inspected the high pressure EGR valve and the intake manifold they've both had a lot of soot build-up, as had the inlet ports which I could just about see. The first time I cleaned the front side of the EGR valve and the EGR pipe to the manifold out but the soot returned within 10,000 miles or so. The soot was all dry apart from an oily patch in the top of the manifold. At some point I'd like to try a proper clean, i.e. manifold off, EGR valve off, inlet ports cleaned etc.

The one time I've cleaned the MAP sensor it was only a little oily. The intercooler core I could see through the hole to be clean. Doing so did not appear to make any difference to the regen intervals. I may clean the MAF sensor as well for good measure though I may leave it as they can be delicate. From when I've changed/cleaned the air filter it has only looked a little dusty.

You can test actuators/valves in Forscan: How to use Output Control mode in FORScan 2.2.* - FORScan forum though I haven't tried it myself for the EGR valves.

The only thing that I have found to consistently increase the regeneration interval other than driving very conservatively was adding half a bottle of Redex DPF cleaner to every tank (the 300 - 350 regen count period in the plot above, 65-70,000 miles in the MPG plot) which also noticeably increased the MPG. I stopped doing this as of late to see what the intervals might drop down to without it. Earlier in the year Toolstation were selling the stuff for £4.50 a bottle though it's now £6.99.

At some point I'll check the resistance of the glow plugs, it should be around 20 ohms to be in spec.

Thanks for taking the time to post this very detailed information. Your regen data appears very similar to mine with a lifetime regen average distance of every 117 miles. In your ownership this appears to have fallen to every 73 miles.

You have done 39,000 miles in 18 months which is the perfect usage scenario for a diesel which should both minimise the number of failed regens and oil dilution. However, all the long journeys appear not to have improve the regen intervals?

Since last October I have done 6500 miles and the Oil life meter is down to 10% and the oil level is half way to the X. I have been using archoil diesel additive in every tank and redex every 3 months.

I have come to the conclusion that the Mazda DPF system is flawed and post the emissions fix in 2019 the software was altered to get the cars to regen more often to counter the excessive soot generation. An active regen in my VW Passat varies from every 250-300 miles.

I am torn between keeping our Mazda 2 as it costs zero road tax, £150/year to insure and averages 65mpg but I know its potentially a ticking time bomb. DPF off/remap or MX-5?

I did change the fuel filter last week and then got a regen interval of more than 100 miles but I doubt they are related.

I am of the opinion that maybe I am chasing rainbows trying to improve the regen intervals. I think I should just stop thinking about it and leave it alone!

 

[mart4856]

I would be interested in seeing what DPF intervals you are currently experiencing. The only thing I forgot to mention was 7. Clean/replace glow plugs. The inlet manifold looks a lot harder to remove with the location of the coolant reservoir and built in intercooler than on the 2.2!

 

[mart4856]

The DPF that was removed had a hole in it & was beyond repair. Car has 110km & used for mixed driving. New DPF is pretty much immediately clogging leading me to believe it’s an underlying issue & not the filter itself. I’ll check out diesel injector specialists, hasn’t thought of that, thanks!

Sounds like it is over fuelling. Is fuel consumption bad? Only other thing I can think of is a dirty or faulty O2/Lamba sensor which cause the injectors to add extra fuel. I think this would cause an engine warning light.
I would like to inspect and clean my upstream 02 sensor but don't know where to find it.

 

[mart4856]

Hi Everyone, I am having the exact same problem with my 2017 Mazda 3, 1.5. Did replacement fuel injectors sort this long term for those who took that route?
Long backstory of rising oil levels, excessive black exhaust smoke (caused by rising oil levels), a new DPF fitted that pretty much immediately blocks again followed by limp mode, TPMS & traction lights ultimately ending now with the car not starting.

How many thousand miles or kilometres has your car done and what is the car mainly used for (short, long journeys or a mix?).

4 injector fitted and coded at a Mazda dealer costs 2000 Euros +. You can buy cheaper unknown quality ones on eBay but these will still need testing and coding.

Was your DPF terminally blocked and if so at what distance? Could it not have been cleaned? Are you using Forscan or another program to monitor the build up of particulate matter and distance between DPF regens.

It might be worth trying to find a diesel injector specialist to test your old injectors spray patterns and check for cavitation!

 

[mart4856]

What would happen if you either disconnect both rubber hoses to the differential pressure sensor or just the electrical connector?

Would this stop the sensor starting a DPF regen or would try and do one all the time? I suspect it would throw a DTC and warning light.

If it worked then the DPF regen would only be triggered after each time 17.1 litres of fuel have been consumed.

 

[mart4856]

Hello, Just want to share my story if someone could find it useful. I have 2014 Mazda 6 driven now about 416 000 km and those kilometres driven mostly by me, so I have owned this car already for years and so quite familiar with it. The car has original DPF and never done anything (wash or clean or else) to it. Usually my interval between regens was between 240-400km, but about six months ago, it suddenly went to around 160km. I read this topic and decided to try replace the exhaust gas pressure sensor and so bought the latest improved version of that and replaced it by myself. (Same time I replaced vacuum pump as error code for it came 5 times within couple weeks, but this shouldn't have any effect on regen intervals.) I didn't reset any learned values of the gas pressure sensor after replacement. First I thought it wasn't helpful as didn't see any significant effect on regen intervals, but now after about 5 or more regens, the inteval has improved every time. Last one I had today was 330km and before that it was 300km so it seems it's getting better cycle after cycle. So, my point is that this sensor can be one reason for too short regen interval, but of course it can be something else as well.

Wow that's some massive mileage. If it's not a typo that's 260,000 miles in 8 years! Are you still on your original injectors? Have you had the EGR, cooler or inlet manifold cleaned? Are you still on your original cam chain? If so that's pretty amazing!