Hi guys

have to share this with you and sorry for yelling but -----

PULL APART AND CLEAN YOUR DK's IMMEDIATELY!

I have had my M70 for a bit over 2 years and in that time it has always had a rough idle (do a search on my username for previous posts and all the things I have tried to fix it - plugs, caps, rotors, coils, lifters, MAFs) and ran a little rich - noticeable difference between banks etc.

Pulled the DKs apart tonight -

MAJOR gunk buildup around armature but more importantly

the brushes that are supposed to contact the armature were not properly contacting the armature - the tracks that the brushes run in were full of gunk and crap from years of the brushes wearing on the armature

PLUS

the gears themselves were covered in gunk and crap - the factory grease had hardened and of course the throttles were hard to move and sticking at points

SO

pulled them apart as per the VERY useful instructions on shogun's website (or e38.org/e32 - highly recommended thanks shogun ur indeed a master!!)

cleaned everything including the armature and gears, put them all back together, got them both back in car, started her up and BINGO

for the first time in years, idle is rock solid and steady - c.750 in park and around 650 in Drive

previously idle was barely above 600 in park and sometimes falling below 600 in drive

interestingly i measured the resistance of the DKs at terminals 6 and 8 and found the following:

DK1 - resistance 1800 ohms closed
DK2 - resistance 2000 ohms closed

the bank run by DK1 idles at about 750rpm, the bank run by DK2 idles at about 650rpm

join the two together and both banks running idle is 750.

BUT ROCK STEADY - no pops, no surges, no hesitation - perfect sewing machine idle!!!! :)

sorry for the long post but this is very exciting news :)

also interestingly, i did a vacuum test on both banks - one pulled about 8-10 inHg by itself (clearly has a vacuum leak - will have to fix this probably the damn intake manifold gaskets) and the other around 16-18 inHg - when both banks running vacuum pulled is around 16-18.

so there you go - any questions you want to know please ask but follow Shogun's instructions (which is also archived at www.e38.org/e32/e32_throttle_body_cleaning.pdf) to the T and it will work perfectly.

i would especially concentrate on cleaning the tracks around the brushes touching the armature of the DK as well as ensuring you put some long life grease on the gears.

Cheers and thanks for reading

750iLinOz
1989 750iL
143k, lachsilber, 17" Alpina alloys

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  • Re: Single most important maintenance EVER!! (LONG) - jamesbarnes 2008-08-26 16:21:57 (106 views)
  • mine idles at 500-600 rpm but no vibration (nt) - alv12 2008-08-25 23:53:58 (94 views)
    • Re: mine idles at 500-600 rpm but no vibration - 750ilinoz 2008-08-26 00:41:18 (93 views)
  • since years I am 'preaching this' ;-) (pic) - shogun 2008-08-25 18:30:34 (226 views)
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        • Re: stuck brushes biggest culprit - 750ilinoz 2008-08-26 20:50:24 (85 views)
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