would there be any problems in doing this with the combined cat/dpf unit? my 325d has this unit. when cleaning , what way should one flush/clean the dpf/cat unit? just got a dpf warning , comes on after maybe 5-10 minutes driving. I feel no loss at all in power, no change in fuel economy. But i have not had the car diagnosed by bmw yet to make sure there is not something else wrong..
With the price of a replacement dpf/cat unit, i will be trying whatever i can, before i go out and buy a new one

HF

 

Well, if you are going to have to buy a new dpf, i would not. Buying a bypass pipe and having the dpf mapped out of the ecu will be far cheaper (and your car will run better). I am currently looking at this option...
My link

food for thought

Gav

 

Why not take in the inside of the DPF out and remove it from the ECU. Saves you paying over £300 for a pipe.

Anyway has someone ever written a software that would force the regeneration? How difficult is it? I assume you just need to trigger the built in mode in the ECU and bypass some parameters.

 

Yes mines a M57N2. I did fix it but it came back after 2 months. Had to hose out the soot from the DPF to force the regeneration.

 

So your saying it came back again after hosing it clean? This is what i'm afraid of....it's why i'm leaning towards getting rid of it altogether. Your right, gutting the standard dpf is the cheapest way to do it, but for some just replacing it with custom made delete pipe is easier (and still far cheaper than the 1200 uk pounds bmw want for a new cat/dpf unit).
I have a contact for ecusafe dpf removal...just need to find out the best way to extract my map from ecu....

Onwards >

 

Gav900. I believe my problem was related to a oil leak, that I removed the swirl flaps or that I used to start up the car on cold mornings in the winter for 10 minutes while standstill just so my baby would be warm when we got into the car. It was cold last year!

I think after the forced regeneration/clean which was done without removing the DPF it did not fully clean it out therefore and the regeneration failed after 2 months. I assume if you dissolve the soot with chemical, it would also dissolve the ash which does not get removed when regeneration occurs.

One thing that puzzles me is why does BMW charge £1600 for a remanufactured unit and must have the old unit back? I'm thinking they clean them out properly, remove the rust and perhaps electroplate to restore the material/coating inside the DPF matrix. I also think once you have cleaned them out the DIY way, you have to reset the DPF in DIS otherwise the ECU will take the age/ash content into consideration that causes failed regeneration.

There must be someone who knows the facts, please post!

 

Carried out a particulate filter test today to check the back pressures. At idle it was 37mbar, the max should be 35mbar. At 2000rpm 139mbar, max 75mbar, at cut-off 4000rpm 270mbar, max 200mbar. See image of test in DIS.

 

Carried out a particulate filter test today to check the back pressures. At idle it was 37mbar, the max should be 35mbar. At 2000rpm 139mbar, max 75mbar, at cut-off 4000rpm 270mbar, max 200mbar. See image of test in DIS.

 

How do you reset the ash content in DIS? Its easy enough to clear the fault codes, but i'm not sure that resets ash content?
The DPF implementation on modern engines (not just BMW) is a right half arsed attempt...you just need to google it and see all the complaints/problems. Even when working properly i personally don't think regeneration is a good thing for a cars engine, running at elevated temps is not good for turbo's and the like.
I have emailed a mobile remap company who can also do dpf delete in software, if i go this way i will take photo's of the dpf being gutted.

Gav

 

I checked the back pressure, results as follows:

75mbar at idle
180mbar at 2000rpm
380mbar at 4000rpm

Now wheres the grinder...