Denox catalytic converter sulphurized - 2008 BMW 1 Series

unbolt or cut it out

Chris, Plugged catalytic's can cause this problem, some GM converters have a access plug in aiding the cleaning of them, but it could be older models. In park,emergency brake on ,rev engine to 3000 rpm approx. and have some body beat (not to hard as to damage) on converter with a heavy blunt object(2x4) and see if it loosen soot,carbon build up and blows it out tail pipe.
To show your appreciation press the helpful button and follow me on fixya for more tips and info

Maybe.
The rich gas smell is probably due to injector problems. The rotten egg smell is sulphur in the fuel, which reacts to the catalytic converter. The rich smell would need to be fixed first by checking the injectors and the engine computer.

The heading cut off your symptoms, it appears. Catalytic converters that are failing can get hot and smell like rotten eggs. Sometimes they break apart inside and cause blockage. Depending on the severity of the condition, it may cause the engine to run poorly or even stall if bad enough.
This is only a possibility, it would have to be checked. The smell of sulphur and considering the age of the vehicle may indicate the converter should be checked.

SECTION 309-00: Exhaust System 2003 Focus Workshop Manual DESCRIPTION AND OPERATION Procedure revision date: 01/24/2003 Exhaust System Printable View (214 KB) Vehicles with 2.0L Zetec-E engine
Item Part Number Description 1 - Bracket 2 - Gasket 3 - Catalytic converter 4 - Bracket 5 - Gasket 6 - Front muffler 7 - Rear muffler 8 - Hanger 9 - Flexible pipe

Vehicles with 2.0L SPI engine
Item Part Number Description 1 - Gasket 2 - Catalytic converter 3 - Bracket 4 - Gasket 5 - Front muffler 6 - Rear muffler 7 - Hanger 8 - Bracket 9 - Flexible pipe

Vehicles with 2.3L PZEV Engine
Item Part Number Description 1 5G232 Catalytic converter 2 5K222 Mounting bracket 3 5K282 Head shield 4 9451 Gasket 5 5A262 Insulator 6 5E292 Converter and muffler assembly 7 9448 Gasket 8 5G203 Flex Pipe NOTE: The exhaust systems shown in this section are production systems.
The exhaust systems are of a two-piece construction for production and five-piece construction for service.
Catalytic Converter
The catalytic converter fitted to the Focus range resembles a small muffler. Because of the high temperatures at which the catalytic converter operates, the vehicle body areas around the catalytic converter are protected by heat shields. The catalytic converter controls three emissions; Hydro carbons (HC), carbon monoxide (CO) and oxides of nitrogen (NOx).
Catalyst deactivation due to poisoning
Sulphur (S) in the fuel can cause deactivation of the catalyst.
Lead (Pb) in fuel can cause a severe deactivation at levels above 5 mg per liter of fuel. It is therefore essential that vehicles with catalytic converters always operate on unleaded fuel.
Zinc (Zn) and phosphorus (P) present in some oils, can cause deactivation if oil consumption is high.
The effect of sulphur is felt most if it is released from the catalytic converter as hydrogen sulphide (H2S). This has an unpleasant odor similar to rotten eggs. Changing the fuel manufacturer may help in reducing this phenomena.
To minimize H2S emissions, it is essential that the idle CO level is within specification and that the engine emission system is functioning correctly. For additional information, refer to Section 303-08A or Section 303-08B.
CAUTION: If temperatures exceeding 900°C are achieved the catalyst substrates will start to deteriorate. It is important that the cause is defined and rectified if subsequent melts are to be prevented.
Catalyst melts are normally accompanied by loss of power due to excessive back pressure. For additional information, refer to Section 303-07A or Section 303-07B.
High substrate temperatures are caused by the ignition or the fuel systems. For additional information, refer to Section 303-07A or Section 303-07B.
Misfires at high engine speed may result in an almost instantaneous melt.

If your engine light is flashing and sulphur smell engine power loss your probably looking at a catalytic converter.However you will need to have a engine scan completed to see what else is wrong as well.

sounds like a restricted catalytic converter. you must, however find out why it got restricted, or it will happen again, from the sulphur smell, i suspect engine is running rich. you need a pro to help you with this problem.

Two things come to mind.

1. Check transmission fluid, it may be low or need changing if it's brown and smells burnt
2. Bad Catalytic Converter; signs are a smelly, sulphur like exhaust, rough engine, excessive heat coming from under the car.

Sounds more like the TPS (Throttle Position Sensor). When the Catalytic Converter goes, usually will get other symptoms like lack of power, bad sulphur smell, & a lot of heat coming from under the truck and depending on where it's located, hot floorboards. If you go to a place like Autozone and get a free diagnostic test, the codes would give you a better idea where the problem lies. Best of luck.
Greg

Rotten eggs is usually a good sign your catylic converter has gone bad or is severely clogged. It will smell bad at first and then you will loose power over time.