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1992 500 SL
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20 Posts
Discussion Starter #1
I recently purchased a car, failed emission and had a high idle. I am told you can not adjust the idle, but making the fuel mix leaner will make idle go down and help with the emissions test. Is that correct? How do you adjust the fuel mixture?

Thanks
 

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Registered
2005 SLK350, 91 300SL with Pano Top, 04 S500, 2015 Tesla Model S
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2,085 Posts
Do not fool around with the mixture adjustment. Anyway, you would have to drill out the ball bearing in order to get at the adjustment screw. On the other hand, if a previous "adjustment" was done, then you might want to do it. Correct way is with a CO sniffer.
But this would be the last resort. A high idle may be caused by a vacuum leak or a faulty Idle control valve, or just the electrical connector to it. Check these things first.
 

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Greek God of the R129
SL500-500SEL-190E
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8,391 Posts
I second mrelbe do that don't touch the mixture.
There is a reason why it is sealed.

Are the rpm about 1400?
Clean the idle control valve with carburetor cleaner, and jingle it.

Regards,
aam.
 
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