In Reply to: Question for all M50 owners posted by Antony on April 11, 1999 at 23:24:37:
: Hey 325 and 525 drivers!
: I've got a peculiar problem with my car (non-vanos M50 mated to a 4-speed automatic). The dealer (a very good one) was baffeled for a while and finally tried out three other M50 engined cars, and concluded: 'All M50's do that'! I find it hard to believe but trust him as he's been rather helpful in the past, so please try this out and see if you can or cannot duplicate the problem.
: Here it is:
: Drive about 65-70 and kick down into 3rd gear for hard acceleration. Watch the tach pass 4000 and klimb towards 5000 (should be up to about 80-85 now). Somewhere between 4 and 5k you should see (and feel) a 200 RPM correction/dropout. You will actually see the needle go backwards. I can make thi shappen every time in 'E' mode and I think most of the time in 'S' (maybe every time, I don't use 'S' that often).
Well, I can tell you (I have a 520iA from 1991) and yes it does that in E or S and in W. Yes they all do that. I had my tranny changed at 160.000km and the new one does the same. So, NO PANIC. It's normal, it has something to do with the couple-reformer (or something).
Hope you're safe now.