Subject: Re: 95% sure it's clogged cats Author: kiwijochen : member since June, 2006 : 2000 posts Posted on: 2008-12-01 13:38:05

Hi,

I owned my 540i E39 in Auckland, what town are you in?

Yes, the engine computer will shut down fuel supply on a per-cylinder basis to prevent cat damage when the engine is not running right. Even a misfire detect on one cylinder will cause a fuel shut-off for that cylinder.

The computer re-adapts itself very quickly, so nothing is required once you have replaced the cats. You can also clear the adaption codes, but when you're testing it you should observe the oxygen sensor values after you replace the cats and make sure they are all OK (using BMW GT1 diagnostics)

Have you read the fault codes?

The engine will generate many fault codes when it is running poorly, the BMW diagnostic system can read the fault codes, and the mechanic uses them to assist in his diagnosis. After the repair, the mechanic clears the fault codes so that the car leaves the workshop with a clean bill of health and a clean fault code memory as well.

If you don't clear the fault codes, you make future diagnosis difficult, as the mechanic has to figure out if the fault codes are old and irrelevant.

PS: for your info, if it's a ex-Japan 540i (it may be) then you likely have full nav and TV installed, and you may be interested to know that that whole system can work in NZ - I got mine going (81997 E39, ex-Japan)

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    • Re: 95% sure it's clogged cats - cfin 2008-11-30 05:24:50 (157 views)
      • Re: 95% sure it's clogged cats - bolkow105 2008-11-30 23:04:08 (135 views)
        • Re: 95% sure it's clogged cats - cfin 2008-12-01 02:03:35 (147 views)
          • Re: 95% sure it's clogged cats - kiwijochen 2008-12-01 13:38:05 (156 views)
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