Mercedes high idle(yes another one) 2100 rpm

Apr 19, 2007 1 Replies
1984 Mercedes 500 sel. I have an extremely high idle, at 2100 RPM. I went to a local Mercedes mechanic, and he let me take a used idle computer and put it in my car to see if it was the problem. That didn't do anything to fix it. I have cleaned the idle control valve, still no fix. When the connector is pulled off of the valve, nothing happens, no change at all. I'm running out of ideas. Anyone?

If you pull the plug out of the idle speed controller while engine is running, it will go faster... if so, then you got a monster vacuum leak... follow the black vacuum hose (rigid 1/4" sized one... and make sure it is plugged in tight into the intake manifold.

Spray carb cleaner at all vacuum hose to see if it affect the idle speed... if so, you got a leak there.

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