Subject: Re: 540 help(long) Author: rick540 : member since April, 2007 : 1117 posts Posted on: 2008-08-20 11:47:04

I still think you could be seing the result of an air leak, but need to check that O2 wiring as well.

It takes very little to render the O2 sensor readings useless for diagnostics, rather focus on the obvious, like manifold gaskets, rubber bellows, air pipes, temp sensors, blocked cats/mufflers, fuel pressure, compression etc. O2 sensor errors are almost never the sensors themselves, but something upstream.

Spray gasket areas with brake cleaner while it is running and see if there is any increase or smooting out of the idle.

Don't forget air leaking into the sump as well. Pulling the dipstick or losening the oil filler cap will affect the idle quality if the system is healthy, if it doesn't there could be excessive blow by or air leaking into the sump.

As much as I like them, these V8 engines don't age too well, too many gaskets and pipes that should all be changed after 10 years if you don't want to be driven nuts by problems like this.

1994 E34 540iA M60
1997 E39 540iA M62


Capetown South Africa
"The Mother City"

• 540 help(long) - my406cid 2008-08-19 09:35:42 (94 views)
  • Re: 540 help(long) - rick540 2008-08-19 13:47:55 (77 views)
    • Re: 540 help(long) - kfister 2008-08-19 21:04:09 (51 views)
      • Re: 540 help(long) - my406cid 2008-08-20 11:00:27 (45 views)
        • Re: 540 help(long) - rick540 2008-08-20 11:47:04 (43 views)
        • Re: 540 help(long) - kfister 2008-08-20 11:30:15 (56 views)
          • Re: 540 help(long) - my406cid 2008-08-20 12:09:24 (40 views)
            • did you try the MAGIC SHOGUN RESET - kfister 2008-08-20 12:52:36 (86 views)
              • Re: did you try the MAGIC SHOGUN RESET - my406cid 2008-08-20 17:36:27 (52 views)