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2013 C300 4Matic, 98 SL500 SP1 Pano, 2014 CLA-250 4Matic
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292 Posts
Discussion Starter #1
I have searched for quite some time but was unable to find anything that matches my issue.

1982 380SL with 36,xxx original miles. After several summer seasons of ‘hair pulling’ I was finally able to resolve the huge vacuum leak (Thank you Chuck) with the discovery of the cracks in the Air Guide Chamber, and the replacement of the OVP, all vacuum lines and connectors, Idle Control Module, Oil Temp Sender, O2 Sensor, Temp Sensor, and the ‘brain’, I was finally able to correctly adjust the duty cycle with excellent (last long haul was 22.7 MPG up from 15.8) results. The only component that has not been replaced is the Idle Control Valve, which has been cleaned as per many posts on this site and others.

The issue I’m currently dealing with is a very intermittent idle issue, but not the typical high idle. The car starts instantly but each time the idle will end up in one of three different ‘modes’. One time I start the car the idle is perfect at 550 to 600 with no miss or hunting. The next time it will be low at 500 to 525 and hunting slightly. Start the car again and it will run up to 800 to 900. As noted above, I have removed and cleaned the Idle Control Valve several times and upon reinstallation the car idles fine until you restart. When cleaning the ICV I noticed a round piece of what appears to be similar to black plastic that is the same diameter as the interior of the ICV which is ‘flapping’ loose inside the ICV with only one small portion of the border still attached to the interior of the ICV. During the last cleaning of the ICV, I took a probe and pushed the plastic ‘flap’ back into the ICV ‘flush’ with the interior of the ICV cylinder which resulted in 550 rpms at idle, until the car is restarted.

My question is if I remove the black circular piece from the ICV will I be damaging the ICV? Additionally, is there any diagram that is available to review to see where the black plastic piece should reside? I’m not trying to be ‘cheap’, it’s just that I don’t want to ‘change parts’ without identifying the problem and wasting money that could be put to better use i.e. new shocks, and the A/C that needs attention. Lastly, I did previously post a picture of the ICV with the plastic piece in question at this link http://www.benzworld.org/forums/r-c107-sl-slc-class/1658381-what-sticking-out-my-icv.html .

Any suggestions, recommendations, and/or diagnosis would be greatly appreciated.
Tim
 

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2013 C300 4Matic, 98 SL500 SP1 Pano, 2014 CLA-250 4Matic
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292 Posts
Discussion Starter #3
Thank you Radiotek, that is very interesting. I finally found time to remove the plastic 'piece' that was inside my Idle Control Valve which has resulted the idle no longer being eratic. I will have to go back and check the duty cycle as the idle is now low at 500 RPM's but stable. I have included a photo of the piece that was removed. I have no idea where the black plastic came from, but is it gone now...



Thank you for the response!
 

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1977 450SL
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50 Posts
Thank you Radiotek, that is very interesting. I finally found time to remove the plastic 'piece' that was inside my Idle Control Valve which has resulted the idle no longer being eratic. I will have to go back and check the duty cycle as the idle is now low at 500 RPM's but stable. I have included a photo of the piece that was removed. I have no idea where the black plastic came from, but is it gone now...



Thank you for the response!
That is very strange. How many sleepless nights have you had trying to figure out what that piece was or where it came from?

Glad you solved your idle problem, gotta love this place!
 
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