[330DE90]

Hi guys,

My 06/2008 325i 3.0 is suffering from slight judder at idle which i know is probably caused by the "Ageing Cat" as per the error code read out.

From start up in the morning the car is a bit sluggish for the first 2minutes, from there its perfectly fine unless i stop at lights and i can feel a slight misfire. Im not sure the NOX sensor is gone but i know for a fact the Cat/s f**ked because i can hear the metallic rattle underneath first 5minutes of driving before i build Revs up.

There is also white smoke every now and again as many others have experienced, it completely stops after a spirited drive though, its got better the more i use the car which backs up my suspicion that there is a possibly blockage in the Cats.

Has anyone done a Decat on one of these engines and eliminated this issue.?
or is a just a matter of replacing the NOX Cats and sensor/controller if need be...
Should i need to but new parts, Where on earth apart from the stealer would i get the Cats

All The injectors where replaced along with HPFP and fuel lines etc as part of the recall so ive eliminated these as culprits.

I hate writing essays but hope someone can help...or suggest another solution .

Thanks]

[alx.]

What error are you getting? Catalytic conversion 29F5?

[330DE90]

Im getting 30E9|DME|Nitrogen-Oxide Catalytic Converter, Ageing

[alx.]

I think it's the nox sensor, not the cat. When i had a cat error and heard rattling it was just a screw untightened that was holding the cat, should also look at that.

To answer your second question it's possible to go decat and just empty them or replace them with performance cats + remove the o2 sensors post cat but it's gonna take a remap.

[alx.]

This might help:

Due to the N53 being a DI stratified lean burn engine it incorporates a NOX sensor installed between the last CAT and rear back box (it looks like an O2 sensor but has a seperate ECU box attached to it under the car), check if it's working using DIS to see if it's reporting the NOX readings and check any F/C relating to this sensor as this is used to measure the NOX content after the CAT.

[330DE90]

i would assume the sensor is working fine because its reporting the Cat is ageing by monitoring gas levels and build up surely? i will check for loose screws etc.
Just been to a garage who say they can Gut the Cat and remap the car for £250..which sounds reasonable enough right?

[alx.]

Originally Posted by 330DE90

i would assume the sensor is working fine because its reporting the Cat is ageing by monitoring gas levels and build up surely? i will check for loose screws etc.
Just been to a garage who say they can Gut the Cat and remap the car for £250..which sounds reasonable enough right?

Yes but you will have MOT issues...assuming you're in the uk? I think they are more strict there than here in Bucharest.

[330DE90]

I am In the UK yes, where can i get the cats after market here in the UK?
is there someone thats an expert with these engines?

[alx.]

Well, any "tunning" shop there in the UK can help you with some aftermarket cats. Look at magnaflow or PILOT. Though i'm pretty sure you'll have to rempa the o2's out regardless.

Still a better option than gutting them.

[frenchi]

The only way to remove this error is using ista/d or rheingold and perform a replacement of nox catalytic converter funtion wich will erase DME adaptations on nox catalytic and the best part is that you will have a much much better mpg.

[330DE90]

Originally Posted by frenchi

The only way to remove this error is using ista/d or rheingold and perform a replacement of nox catalytic converter funtion wich will erase DME adaptations on nox catalytic and the best part is that you will have a much much better mpg.

Frenchie, How do i perform this action? my mechanic said he can gut the cat if it cannot be cleaned, he also had Ista/P and i think Ista/D

[frenchi]

Originally Posted by 330DE90

Frenchie, How do i perform this action? my mechanic said he can gut the cat if it cannot be cleaned, he also had Ista/P and i think Ista/D

Tell him to take a look on ista/d service functions you got something like replacement of nox catalytic converter reset function...once executed your error will be erased and DME will adapt to the new consumption...about 1-1.5 l/100km better mpg

[Phil325i]

OP what mileage has your engine done? This is the first case I've read of N53 possible CAT failure. Unstable idle issues are, however, quite common but caused by a number of things including: plugs; coils; MAF sensor; injectors; VANOS solenoids (to name but five!).

I wouldn't rush into doing anything drastic to your CAT until you're absolutely sure its the cause of your idle issues...

[330DE90]

Originally Posted by Phil325i

OP what mileage has your engine done? This is the first case I've read of N53 possible CAT failure. Unstable idle issues are, however, quite common but caused by a number of things including: plugs; coils; MAF sensor; injectors; VANOS solenoids (to name but five!).

I wouldn't rush into doing anything drastic to your CAT until you're absolutely sure its the cause of your idle issues...

its just hit 95k, i have had my injectors done, coil pack, plugs, all the recall work carried out, The codes i have coming up refer to the NOx Cat & today Oxygen sensors before cat

[Phil325i]

Originally Posted by 330DE90

its just hit 95k, i have had my injectors done, coil pack, plugs, all the recall work carried out, The codes i have coming up refer to the NOx Cat & today Oxygen sensors before cat

Then it sounds more like a sensor issue than a failed CAT...

[frenchi]

Ok, let me give you few details on how it works exactly on N53 engines... when you got an aging or faulty nox sensor Dme triggers more frequent desulphurisation of nox catalytic converter... once DME detects more then 2 desulphurisation on less then 2000km it triggers automaticly an Ageing cat error that can't be erased - consequence is higher fuel consumption because dme try to keep catalytic converter on higher temperature to burn the nox inside... it doesn't mean at all that your cat is full or dead just less effective.

[330DE90]

the first few mins of driving i get misfire and a rattle from underneath like tin cans in my exhaust hence my worry about the CAT, in terms of fuel consumption its pretty bad now yeah and i cannot hold the revs at 800rpm without them dropping, currently not using it anyway coz i may have bricked the cas while using Ista :/

[SGanesh]

frenchi, you are absolutely right about the N53 stratified engine operation.

I have the same error (30E9) reappearing even after a BMW specialist forcefully regenerating the NOx converter. I understand that without permanently clearing the error, MSD80 DME will not allow the switching of Homogeneous mode to Stratified or Homogeneous-lean mode. This means the AF ratio is always at 1 lambda rather than 1.8 lambda and above. This has significant effect on fuel economy.

I have tried resetting the NOx adaptations and desulfations in INPA but that made no difference. I have technical issue running the ISTA on my computer.

My question is, before I try and get the ISTA working, I want to know if the ISTA can permanently clear the error?
Like the NOx regeneration process, does it require to run the engine at certain conditions such as 110-115 kmph for 20 mins to get the exhaust gas temperature above 600°C?
What is the success rate?
Have you come across any guide online?

Thank you
Sakthi

[Tr1ppy]

Also consider the Nox Emulator (aka Noxem) if you're having nox sensor issues.

I'm not sure if it's a better option to remove the nox function from the DME completely or go with the Noxem though as I've never tried either.

https://bimmerprofs.com/products/

[SGanesh]

Tr1ppy, thanks for your response.

I have seen this. I don't think this will resolve the 30E9 error.

My NOx sensor is working fine. See attached screenshot.

[frenchi]

Originally Posted by SGanesh

Tr1ppy, thanks for your response.

I have seen this. I don't think this will resolve the 30E9 error.

My NOx sensor is working fine. See attached screenshot.

Only way to erase this error with Rheingold is to execute the function for Nox catalytic replacement telling the car that you got a brand new catalytic ,there is no other way.

[marcin_e92]

Originally Posted by frenchi

Only way to erase this error with Rheingold is to execute the function for Nox catalytic replacement telling the car that you got a brand new catalytic ,there is no other way.

Hi frenchi,

Have you done this? did it work for you?
I have the same code for ageing cat and wanted to know if this works and whether its a short term fix or long term.

Thanks in advance
Marcin