Mazda CX-5 2.2 SkyActiv-D - DPF filling fast

[Christian89]

Yeah I changed mine, no difference as far as I can tell. Perhaps it improved slightly. I didn’t replace the differential pressure sensor to the left of the exhaust pressure sensor, perhaps I will try that if the injector test comes back fine.

[Christian89]

Tests are back. It is the injectors, all poor spray patterns and evidently of dribbling. Hopefully that’s all there is to it.

[spektr]

So, what will you do now? Buy new injectors, refurbished? On autodoc for instance the price is much lower than at the dealer.

[Christian89]

I haven’t gone to a dealer, just a well run local I trust. Been quoted £1921. They only use genuine parts. Should have it back early next week, I’m desperate to drive it and see if it’s changed.

I guess I just didn’t get as low as the 32 mile mark to get the warning light. It’s diabolical that the particulate matter is 7 times what it should be before it gives you a warning. I only hope it hasn’t damaged the engine.

[spektr]

Ok, post back some info after the repair.

[Christian89]

Injectors have been replaced and the first regens occurred after about 120 miles and the second at 180, May even get more out of the third, however I do a mix of town and motorway driving. Fuel efficiency has improved to about 55mpg which I’m sure will be much better in the summer. It’s the town driving which kills it. Acceleration is also massively improved once the car gets moving, however, still get a bit of judder when pulling away but I’m assuming that’s the clutch or condensation in the clutch that a few other owners have reported on forums. Idle still feels a bit choppy sometimes, mostly when the engine has just started and is cold.

Spektr, did your performance/idle improve when removing the egr valve with the cooler? That’s probably my next step. How come you haven’t removed both? Is the fuel consumption increased that much when removing the bypass valve?

[Mareng]

Christian,
That's good news that they have found the cause, same problem as mine.
The poor spray pattern is caused by the holes wearing due to cavitation erosion as the small particles of fuel as high pressure pass through the nozzle they implode and subect the nozzle holes to a shot peening on a minute scale which subsequently wears the holes. This is due to poor materials or the incorrect heat treatment of the nozzles causing them to be softer than required.
I didn't feel any change in acceleration etc, but a great improvement in fuel consumption, lube oil contamination, regen frequency. Even though the dealer changed the DPF DP sensor, thinking it was that it wasn't as he changed it twice and then twigged there cannot be that many bad sensors, I still have the original loose in the garage.
Each time you fill up log total regens (subtracting previous from present will give you number of regens in that period, apply it to the mileage), oil contamination and mpg. Put these readings on a graph. MPG has its own graph with pence /mile . A 2nd graph with miles / regen and LO contamination. They tend to act together but in opposite directions.
A picture tells a thousand words or numbers.

I just hope your man followed the injector replacement procedure religously as set out by Mazda.

[zdarova]

Hi DPF team,

The regenerations distance started to decrease gradually again from 140km to 60km. Note that now I'm at + 165k km.

I notice that often PM_GEN is less than 1 g/L but PM_ACC is reaching 6 g/L hence triggering the regeneration (I have the H sw)

Also I see that the EGR_ERR is at 99.22%, meaning the valve is not closing correctly from my research. Since the intake+EGR was cleaned this summer, I suppose that the EGR might not work properly.

Note that in July I checked the injectors at a specialized center and replaced that washers and the analysis resulted that there were no issues with the injectors.

As a sum-up of the actions I did in the last 2,5 years:
1. Cleaned the intake 2 years ago and this summer after 40k km
2. Cleaned the DPF a couple of time with Wurth DPF foam or similar inserted before the DPF - it helps, but it isn't last more than 2-3 months.
3. STP DPF additive helps usually by doubling the distance, but I'm afraid of abusing from it too much as it might damage the injectors nozzles
4. The H2 intake cleaning last year - it helped for a couple of months

I have now a chipped SW that gives me more torque and HP, I suppose this also increase the regeneration frequency.

Since the current calibration SW now is SH7M-18881-H I was thinking to change it to SH7M-18881-B and disable the EGR using a custom ECU firmware instead of trying to change the EGR.

If this does not work I should evaluate to sell the car and go for the Mazda with the AdBlue as from I heard it's a more robust engine (after August 2018 - in the back is has only one exhaust pipe)

Do you think my analisys make sense?!

[boda989]

Hi. I have the same problema with mu cx-7 2.2mzr-cd r2 motore . Every 50-60 km I have DPF regeneration and of I push hard even less. First I blanked EGR valve and then It was 80-100km . My consumption was 9lt/100km with normale mix use . I realise that my ECM riduce injection time for compensate nozzle worn. More ECM need to reduce time of injection more pm_acc and pm_acc_dsd increase . For prof my self I ordered 4 nozzels from AliExpress for 70 euro. After i changed nozzels evrithing back to normal. Now i have 250km beetwin regeneration. Sory my bad english.

[Christian89]

Thanks Mareng, think the injectors are holding fine, the regens are the main thing ive noticed. Last one had a really long interval well over 200 miles. Injector correction values look good as well.

Zdaradova, I had the exact same and % error the EGR, but i think the egr just shows that error when they shut. I had mine cleaned out and they were still doing it, youll notice if you put the egr desired and actual on a graph that when you stop the vehicle and the egrs desired and actual go to 0% as it closes and the egr error goes to 99.2%. I think the error PID on this car just measures the flow. I could be wrong, i do get a rough idle and my car definitely felt better when i unplugged the egr, minus the limp mode.

Does anyone know whether our vehicles have 2 ECT sensors, i have one PID that says 'engine coolant sensor 2 voltage - 135 C', this is constant and at startup. Whats confusing is it says voltage yet displays as temperature. Is this the same with any of your vehicles? Wonder if it could be running lean at startup due to this?

Thanks