My tach shows about 650-700 in idle, drops slightly in gear. Neutral was at about 900 prior to the chain rails breaking and subsequent restoration of the engine. Hard to know what reduced the idle--new chain and rails, valve guide seals, new fuel injectors and air distribution lines, plenum gaskets, left side head gasket and exhaust valves, or general cleaning of the engine.

If i had to pick one part of the work that MAY have affected idle speed, it would be replacing the vacuum connectors at the throttle body (under the intake manifold--no way they could have held a vacuum before. Mike Tangas documents these buggers very well in his 560sel accomplishments thread (almost a bible for 560 owners) but they are much easier to do with the intake off!!

The other strong possibility is the air distribution lines to the injectors, one of mine was cracked and that may have helped. I did NOT change or clean the cold start or idle control valves, though they were both removed and replaced. Best wishes.

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Earl McLain
'02 C230 Kompressor
'89 560 SEL "Frau BlueCar" (retired April 2004)