Q: Sulphur blocking the catalytic converter

asked by on August 04, 2016

My car has the dreaded injector coil issue and I’ve already replaced it two times! Currently, it is running better but the engine management light comes on randomly. The dealership told me this is caused by sulphur blocking the catalytic converter. They blamed me that this is caused by the way I’m driving. I was also told by a tech that my car is remembering how it used to be driven (ex-fleet car with mostly highway miles). Now that I own the car and it’s not being driven as much as before (I just drive around town and shopping) this is the cause for the sulphur blocking the catalytic converter. He said it’s not a warranty issue, but instead the way it’s being driven. His solution is to desulphurise the car and this can be done by my regularly driving it on the interstate at 70 mph for 30 minutes. This seems rather impractical to me, plus such a bother! This was also questionable because I was driving on the interstate the second time the warning light had come on and was going over 70 mph. When I bought the car I was aware there was an unlimited mileage warranty, so I don’t think it’s unreasonable for me to expect BMW to honor this! If a car can’t perform well on short trips, then there must be something wrong with it! This is a petrol engine - not some diesel engine. In addition, I was told that the blocked catalytic problem can be caused by the injector coil. To add to my problems, when I got my car back from the garage, there were fresh scratches on the front, side bumper!! I will call BMW about this also. Would you please give me your advice, diagnosis, and solutions for my car?

Hello. If you had an injector coil issue, then that will usually cause the converter to become clogged and fail. If it is clogged, then it needs to be replaced as driving it will not clear it up. You will have multiple failure of the coils over time until they are all replaced. Since you have the unlimited warranty, then this should be covered. I would advise that you call BMW’s national customer service line to get them involved as they should be able to offer more assistance. If you would rather have an independent technician inspect this, a certified technician from YourMechanic can diagnose the warning light that you are experiencing and let you know what next steps are needed.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Toyota Camry 2009 stopped suddenly while driving wont start back up

Hi There, It sounds like you may have a faulty electrical connection or potentially a weak or dead battery. The other possibility that may be quite likely could be a failing alternator as indicated by the fact that the car...

Check Engine code for catalytic converter.

This can be because the catalytic converter is bad or the sensor is defective. A qualified mechanic would have to scan the vehicle and check for broken up or rattling converter signifying its coming apart inside.

I have a 2003bmw 525i , I mistakenly put tranny fluid in the power steering canister now it is hard 2steer what 2 do now

Hello, thank you for writing in. While it is not terribly uncommon to run transmission fluid in the power steering system (they are both hydraulic fluids), newer vehicles tend to be designed to be used with specific fluids, and do...

Related articles

What Does the Fuel Cap Warning Light Mean?
The fuel cap light tells you when a leak has been detected in your car, most likely from a loose gas cap.
What Does the Washer Fluid Low Warning Light Mean?
The washer fluid low light warns you when your windshield wiper fluid needs to be checked and refilled soon.
What Does the Steering Lock Warning Light Mean?
The steering lock indicator light means your steering wheel is locked and can not be moved, usually until the vehicle's keys are present.