1983 500SL 107 series revs up to 1500rpm

[daniel]

my 500sl has started to rev up on its own to 1500rpm, it stays there from 5mins to 15/20 mins, then drops back down to idle. There is no pattern to this happening. Sometimes it does it fron cold. other times it can be an 15mins or more before it does it. I have put a test lamp on the idle speed adjuster (no:23), the lamp goes out, then it revs up, this indicates to me its not the idle speed adjustor. (It has the same effect if I pull the wire off the idle valve). Has any one come across this problem? I can locate the temp switch (no:20) but I am unable to locate the electronic idle speed control unit ( no:21)

 

[Rasputin]

Idler Control Unit

The Idler Control unit is located under the drivers side (right-hand-drive cars) footwell. Unscrew the cover and you will see it as in the pic.

 

[Terry Lloyd]

To Daniel From Terry Lloyd - Idle Problem

Daniel, I have the same problem with my newly aquired 380SL (81 Model) I changed the idle control slide valve (expensive) to no avail. Did you solve your problem? I would be grateful for any help.
You can reach me at terrylloyd@gasconnect.co.uk