DPF fill rate changing

[Jules13]

I've got the 2012 w212 E220cdi.
On my commute I have the Autel Maxi diagnostic plugged in for live data, and have done for the last year.
Some days my DPF fill rate is way worse than others. It's high anyway as it's had a remap, so notorious for extra soot. In 26 miles ( 7 on motorway) some days it goes up by 16%, then other days it's by 45%. It's early morning so traffic very light and driving style damn near identical every day.
What could cause such varying soot levels? I assume if it's something like a MAF, or injector etc, it would be the same every day, but I'm trying to figure out what could vary it so much.
It's recently had new, correct Merc oil change, at the garage and had turbo pipes and turbo inspected, all OK.
Any suggestions?

 

[M80]

Regens at 160 miles at best, 60 miles when bad.
For me getting the MAP back to original would be a priority, and go from there.

Do you have the MB recall for emissions? That'd do it.
Many report that MAP gives worse consumption, but in your case it would surely be improved.

 

[Jules13]

Remap is coming off Friday so I'll update after a few drives. As for MPG, when I had it remapped in 2019, I changed jobs so commute was totally different so can't compare fuel figures, but I regularly get 54-58 mph.

 

[M80]

Remap is coming off Friday so I'll update after a few drives. As for MPG, when I had it remapped in 2019, I changed jobs so commute was totally different so can't compare fuel figures, but I regularly get 54-58 mph.

Is that a fill to fill calc? Remaps are known to possibly corrupt the OBD.
Otherwise, that's a good return.

 

[Jules13]

Just the dashboard info but the last time I did a fill to fill calc it was pretty close.

 

[onefortheroad]

but I regularly get 54-58 mph.

Is it in limp home mode





















































I know you meant mpg.

 

[Jules13]

Is it in limp home mode





















































I know you meant mpg.

****** auto correct No limp mode at the moment, but if that regeneration to driving time percentage goes above 15%, it goes into limp mode but with no dashboard lights.

 

[onefortheroad]

****** auto correct No limp mode at the moment, but if that regeneration to driving time percentage goes above 15%, it goes into limp mode but with no dashboard lights.

I'd suspect the dpf pressure sensor is on its way out ,rather than thinking the dpf is full of crap tbh. Get live data from your scanner for it.

 

[Jules13]

UPDATE. The remap was taken off today and it's made no difference at all. When I first started having live data whilst driving, about a year ago, I changed the pressure sensor and that made no difference either. Still no fault codes and drives fine with no symptoms, just a DPF that fills about 1% per mile. A regen, even after a DPF spray cleaner has been used, only goes down to about 30% and it triggers the regen at 100%.
Choices now are DPF removal, full soak and clean at a specialist.
Boost leak test.
Injector testing.

 

[Jules13]

For almost a week now, the DPF is filling even faster. 26 mile commute and it's going up by 40%, every day except today where it's back to normal at about 20%. It's had a new back pressure sensor from Bosch about a year ago, so that shouldn't be it. Same petrol station fuel, same commute, same everything. What could be a variable that creates soot? It's as if something is sticking, as yesterday I did some heavy right foot and today it improves?

 

[M80]

Could the DPF be full of ash?

 

[Jules13]

Could the DPF be full of ash?

DPF cleaned out just over a week ago with a Wynns spray which cleared it right out and allegedly clears ash too. Garage also did forced regen and reset all the figures.

 

[V6Matty]

After making so many changes you might need to let it be for a while until it’s relearned everything, that can take a few hundred miles but patience may be key here,
That said I’d be wondering if you have slightly leaky injectors, that may explain the fill rates

 

[onefortheroad]

Icarsoft can also tell you a load of cock-a-hoop at times about dpf levels etc.

 

[Jules13]

After making so many changes you might need to let it be for a while until it’s relearned everything, that can take a few hundred miles but patience may be key here,
That said I’d be wondering if you have slightly leaky injectors, that may explain the fill rates

Leak off kit ordered on Amazon and being done this weekend.

 

[oigle]

Majority of particulates are caused by the egr reducing the O2 level of intake air. My Fiat Ducato had the egr disabled and I have not seen the dpf regen light come on for ages. Did a few times before I deleted the egr. Just look at the mess a sticky egr causes with particulates smoke on non-dpf vehicles. They are a right PITA.

 

[ajlsl600]

Majority of particulates are caused by the egr reducing the O2 level of intake air. My Fiat Ducato had the egr disabled and I have not seen the dpf regen light come on for ages. Did a few times before I deleted the egr. Just look at the mess a sticky egr causes with particulates smoke on non-dpf vehicles. They are a right PITA.

What a surprise, not!

 

[mersum1es]

Is exhaust after DPF check that there is no blockage?

Back pressure sensor (why not boost sensor too) behaves ok?

Double check on boost leaks?

pressure sensor lines cleaned/open?

 

[Jules13]

After the DPF was cleaned, the fill level drops down to 25%, and then slowly gets worse after each regeneration. After about 2 months of driving, it only goes down to about 55%, then it's time for another clean. No sensors are giving any faults so I swapped the back pressure sensor just to see if it made any difference, which it didn't. Boost leak being done soon, and this weekend is the diesel leak off test. I'll blow out the sensor pipes when next cleaning the DPF.

 

[Jules13]

Right. Diesel injector leak off test done. Ran for 2 and a half minutes and got a pretty even 25ml from each one, so 10ml per minute. Any idea if that's within a tolerance?