Question about 1986 Mercedes-Benz S-Class

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Too fast idle running speed.

420 sel 1986. 9000 miles since engine recon.

The idle running speed is 700/1000rpm. Beleive that's too fast. Expect to be under 500rpm.
What's you advice pls.

Would it be the air speed control valve ? or something more serious ?
Thanks

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Typical idle for this motor is right around the amount you have described. Check to see if any check engine lights are on, or if the ABS light is on. A typical issue with this motor is the OVP relay that when not operating properly causes the engine to rev much too high (~1500-2000). Also do your revs drop significantly when you put the car into gear? If not then there really isnt an issue. When the motor is idling too high and you stick it into gear the car will typically lurch really hard.

Posted on Sep 19, 2009

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