Symptoms of catalytic converter failure

Mekihariz · 11-05-2021, 03:47 AM

Hi,

Anyone here kindly advises about the symptoms of a catalytic converter failure.
If it is indeed faulty can it cleaned or it needs straight replacement.
Thank you in advance.

DanG · 11-05-2021, 09:02 AM

Here is a link for you: https://palmbeachgarage.com/catalytic-converter/

I believe BMW is required to warranty catalytic concverters for 8 years or 80,000 miles.

NoGuru · 11-05-2021, 09:24 AM

Drive it hard! That is the best way to "clean" it. If you get any stuttering or misfires and you can't get it cleared out, you might need to replace it.

tdott · 11-05-2021, 09:32 AM

Sometimes it could be easier to unbolt it and inspect it physically.

Problems can be intermittent like misfires, rough running, etc.

AnotherM · 11-05-2021, 02:09 PM

Bmw just replaced both of my cats under warranty. Im at just under 60k miles.

Only issue i ever saw was a repeated intermittent cel for catalyst inefficiency.

The procedure for inspecting the cats before replacement per BMW is to pressurize the exhaust system, test for leaks, followed by unbolting from the turbos and visually inspecting.

jko415 · 11-17-2021, 03:54 PM

the car should throw a fault code if the catalytic converters are below efficiency. if they are clogged it will give you performance issues under load. these are replacement pieces, no way to clean or repair them.

cooolone2 · 11-17-2021, 10:08 PM

Lol, in addition to the above, after a nice drive, take a look under the car, the converter will be a different color usually when failing as it is usually blocked...

E90lova · 09-24-2023, 12:58 PM

I think it's amazing how close the holes are on the stock cats on my 2014 335 Xdrive. Looks like it would be easily clogged.

11-05-2021, 03:47 AM	#1
Mekihariz Registered 4 Rep 2 Posts Drives: m5 Join Date: Nov 2021 Location: Seattle iTrader: (0)	Symptoms of catalytic converter failure Hi, Anyone here kindly advises about the symptoms of a catalytic converter failure. If it is indeed faulty can it cleaned or it needs straight replacement. Thank you in advance.
	Appreciate 0 Tweet Quote

11-05-2021, 09:02 AM	#2
DanG Major General 10661 Rep 6,937 Posts Drives: 2018 M2 AW DCT Join Date: Aug 2012 Location: Seattle, WA iTrader: (1) Garage List 2018 BMW M2 [7.68]	Here is a link for you: https://palmbeachgarage.com/catalytic-converter/ I believe BMW is required to warranty catalytic concverters for 8 years or 80,000 miles.
	Appreciate 0 Quote

11-05-2021, 09:24 AM	#3
NoGuru Major 772 Rep 1,418 Posts Drives: 335is Join Date: Apr 2017 Location: MI iTrader: (0) Garage List 2021 Chevy Silverad ... [0.00] 2002 Jeep Cherokee [0.00] 2014 CTS [0.00] 2011 335is [0.00]	Drive it hard! That is the best way to "clean" it. If you get any stuttering or misfires and you can't get it cleared out, you might need to replace it. __________________ 2011 335is DCT BQ Tuning / BMS CAI / VRSF kittyless DP's / Synapse BOV and charge pipe / 7" VRSF Race FMIC / Walbro 535 and 450 on BMP4 / E90 tune / Diff Brace / PR Coils / Relocation Inlets / DAW Stage3+ Turbos / MMP port injection / xHP Stage 3 / FPR and -6 fuel lines
	Appreciate 0 Quote

11-05-2021, 09:32 AM	#4
tdott Brigadier General 3943 Rep 3,988 Posts Drives: M3 Join Date: Nov 2010 Location: South FL / 6ix iTrader: (4)	Sometimes it could be easier to unbolt it and inspect it physically. Problems can be intermittent like misfires, rough running, etc.
	Appreciate 0 Quote

11-05-2021, 02:09 PM	#5
AnotherM Cole 321 Rep 498 Posts Drives: 2016 m5 CP Join Date: Oct 2020 Location: AZ iTrader: (0)	Bmw just replaced both of my cats under warranty. Im at just under 60k miles. Only issue i ever saw was a repeated intermittent cel for catalyst inefficiency. The procedure for inspecting the cats before replacement per BMW is to pressurize the exhaust system, test for leaks, followed by unbolting from the turbos and visually inspecting.
	Appreciate 0 Quote

11-17-2021, 03:54 PM	#6
jko415 New Member 2 Rep 6 Posts Drives: bmw 335i Join Date: Nov 2021 Location: SF, CA iTrader: (0)	the car should throw a fault code if the catalytic converters are below efficiency. if they are clogged it will give you performance issues under load. these are replacement pieces, no way to clean or repair them.
	Appreciate 0 Quote

11-17-2021, 10:08 PM	#7
cooolone2 Captain 625 Rep 706 Posts Drives: 20' M240iX B58, 01' 330XI E46 Join Date: Jul 2019 Location: NY, USA iTrader: (0)	Lol, in addition to the above, after a nice drive, take a look under the car, the converter will be a different color usually when failing as it is usually blocked...
	Appreciate 0 Quote

09-24-2023, 12:58 PM	#8
E90lova Private 24 Rep 97 Posts Drives: F30 335xdrive Join Date: Jul 2013 Location: Boston iTrader: (0)	I think it's amazing how close the holes are on the stock cats on my 2014 335 Xdrive. Looks like it would be easily clogged.
	Appreciate 0 Quote