text: From digest.v7.n557 Sat Nov 8 12:35:42 1997
  From: "Ian Solomon" <irs_at_mailbox.uq.edu.au>
  Date: Sat, 8 Nov 1997 19:09:27 +1100
  Subject: E12 pinging and Driveline Vibrations - Long
  It's been a while so I thought I'd bring you up to date on the E12er. I had problems with both pinging in the Euro 528i motor under hard acceleration, and a drumming type vibration at 95-100 kph. (55 - 60 mph) which I had narrowed down to a shot rear uni joint.
  With advice from Samir (gofast) I re-routed the distributor vacuum advance and retard lines to provide mechanical advance at low revs and retard the timing a small amount to prevent the pinging at higher revs. This seemed to work for a while but the fuel consumption went through the roof. The engine seemed to hesitate a touch just off idle, and then was okay. The pinging however returned, just as bad and just as annoying. I eventually set the vacuum lines back to their standard positions and reset the timing by ear. Since then I have been getting the best fuel consumption I have ever got with the car (23-24 mpg at 50-50 highway-suburban). Could the pinging be caused by low octane fuel. I know the Australian Government has been cutting the octane rating on our "Super" leaded fuel, so would using a mixture of "super" and premium unleaded be the answer. Any comments or suggestions would be appreciated.
  Samir, if you're lurking, sorry, I've lost your address but would like some more advice on this. I checked the plugs and they are gapped at 0.035" as per your suggestion. Where do I go from here?
  When I removed the driveshaft for an inspection, I found the rear uni was shot. I found a place here in Brisbane who fitted a replacable yoke to the shaft and re-balanced it. Their report showed the front shaft was bent (0.025") which they straightened. A new centre bearing was fitted. When I re-installed the shaft, I was not able to put the 2-3mm preload on the centre bearing as the Haynes manual recomended as the sliding bolts were at the end of their slots.
  Result: Still drumming and vibrating at same speed. I then removed the shaft again, and got the shop to rebalance it. They said it was okay *but* moved some weights anyway. I discussed the preload on the centre bearing, and the tech said that it should not be pre-loaded. Hmmm! Do I listen to him or to BMW-AG? Answer: BMW I refit the shaft, this time cutting slots into the mounting holes of the centre bearing so that I can preload it. Result: Still drumming and vibrating at same speed. I remove and rotate the shaft one set of holes on the transmission output shaft.
  Result: Still drumming and vibrating at same speed.
  Okay, what do I do now? Due to only having two demerit points left on my licence, I *have* to travel at 100 kph on the highway and this vibration is driving me mad.
  Could it be a bent half-shaft? What about something in the transmission? It's an auto BTW.
  Heeeeelllllllllllp !!!!!!!!!!
  RE12DUHTKU
  BMW Club Queensland. Australia
  See my car at www.powerup.com.au/~irs/iansstuf.htm Unofficial Homepages: [Home] [E12] [E24] [E28] [E30] [E34] [E36] [Z3] [E39] [E46] [X5/E53] [ALL] [ Help ]