The mechanic suggested removing the Catalyst converter ...please advise.

[Chad535]

He claimed that he will remove the catalyst, fitting a replacemnt that comes on non-catalyst cars. He said that he will keep the O2 sensor, and Temp sensor intact to avoid any engine problems.
Would that have any adverse effects??, will the emissions be worse than a non-catalyst standard 535i ?

[Bruno]

Why???

Do not do it, you might have some major problem passing emission test after that.
My 535i E28 (almost the same engine) didn't pass emission with dead cats. No matter what.

[Unregistered]

If you mechanic lives in California, he just became eligible for a $50,000 fine and potentially a visit to Jail. The bottom line is that your performance will not improve without the cat and your car will cause about 100 times the polution that it would with a Cat. Unlike cars that were built in the 1970s, modern cars are designed with Cats in mind and have virtually no performance increase from their removal. In fact many cars produce less power without the cats.

Cary

[Chad535]

Well...., the Cat seems to be in a miserable condition......and many cars around here never came with cats......the local stealer quoted 2450 US$ for a new one. i am not looking for performance here, i thought some of these M30s were fitted without cats and if removing the cat makes emissions similar to a stock non-cat car.......everyone will be happy.

[Chad535]

By the way i just realized one pst below "Emissions problem" by Kentish.....he says that his 540i came with no cats, and no O2 sensors.....what i am worried about is that E34s were never manufactured without cats, and if they exist that must be the work of someone having exactly my evil ideas.... ;-) .....that would make my task more difficult.

[Bill R.]

in and what are the emission laws in that country....I wouldn't recomend removing the cat but contrary to what cary says the emissions aren't 100 times more if you remove the cat..There are numerous aftermarket cats that you can replace the stock one with that will work fine for you for much less than the price you were quoted.
Why does your mechanic think you need to replace the cat? you've asked about a number of problems before linking to the o2 sensor and cat in the past...








By the way i just realized one pst below "Emissions problem" by Kentish.....he says that his 540i came with no cats, and no O2 sensors.....what i am worried about is that E34s were never manufactured without cats, and if they exist that must be the work of someone having exactly my evil ideas.... ;-) .....that would make my task more difficult.

[Chad535]

I live in United Arab Emirates, and many non-cat cars here pass the emissions test. i will describe the case....
a dignostics scanner returned an O2 sensor failure code, upon that i purchased the O2 sensor and was about to install it when the mechanic suggested this idea claiming that a 14 years cat must have got so restrictive and worn out....so why not removing the cat while keeping the O2 sensor in place......sounded logical till i got some negative responses ;-)
unfortunatly......in UAE it is not easy to get anything, even a stupid PS pressure hose has to be ordered from Germany by the dealer......so forget about getting a 3rd party cat. in addition to that mechanics here tend to work on trial and error basis rather than educated approaches which lead me to think that removing the cat my eliminate one more object of gussing for my poor mechanic, and make everybody's life easier finding out why the engine vibrates sometimes. I am originaly from Lebanon where BMWs enjoy a care and respect and good maintenance....but here !!!

[Bill R.]

leave the cat alone for now and try that new o2 sensor first, Is there any rattling to indicate that the cat has broken up internally? Usually when they fail catastrophically the core will break up internally and you can hear it rattle when the engine is running...




I live in United Arab Emirates, and many non-cat cars here pass the emissions test. i will describe the case....
a dignostics scanner returned an O2 sensor failure code, upon that i purchased the O2 sensor and was about to install it when the mechanic suggested this idea claiming that a 14 years cat must have got so restrictive and worn out....so why not removing the cat while keeping the O2 sensor in place......sounded logical till i got some negative responses ;-)
unfortunatly......in UAE it is not easy to get anything, even a stupid PS pressure hose has to be ordered from Germany by the dealer......so forget about getting a 3rd party cat. in addition to that mechanics here tend to work on trial and error basis rather than educated approaches which lead me to think that removing the cat my eliminate one more object of gussing for my poor mechanic, and make everybody's life easier finding out why the engine vibrates sometimes. I am originaly from Lebanon where BMWs enjoy a care and respect and good maintenance....but here !!!

[Chad535]

Got it.....i will try replacing the O2 sensor first, by the way a local shop quoted 120 US$ for a non-cat replacement ....... it is damn tempting.

[molesz]

there are some E34 models without O2 sensor but they were all fitted with cats.
Mine was made for Italian market, no O2 sensor, unregulated 2stage cat, but the DME allows retrofittnig a new cat with O2 sensor (even got the 4 wire cable for it with factory protective plug on it).

[Bill R.]

there are some E34 models without O2 sensor but they were all fitted with cats.
Mine was made for Italian market, no O2 sensor, unregulated 2stage cat, but the DME allows retrofittnig a new cat with O2 sensor (even got the 4 wire cable for it with factory protective plug on it).

[Steve_M535iA]

there are some E34 models without O2 sensor but they were all fitted with cats.
Mine was made for Italian market, no O2 sensor, unregulated 2stage cat, but the DME allows retrofittnig a new cat with O2 sensor (even got the 4 wire cable for it with factory protective plug on it).


Hmmm, My 1991 535i has no O2 sensors nor does it have a CAT at all. Thats how it was made. The fuel filler shows "Leaded Or Unleaded" so it was never meant to be that way when it was shipped to the UK.

Running a code scan never shows any msg's about O2 sensors or the like. So I guess that maybe an early UK/EU car could have been spec'd LHD for the US or Canada?

HTH

Steve

[kentish]

Same thing here. I dont think there is O2 error message in my 540i.

My E34 518i 1990 did not have o2 and cat too.

Kentish