[W126 Coupe] Intermittant high idle question

[Dick Spellman]

Here is what I've got.  10 ohms at the connector steady.  Tapping of the air slider valve does not influence this value so I presume the connector to coil wires (2) are good.  I removed the air slider valve and gave it a shake.  I hear the faint click of the valve.  I cleaned out the carbon using carb cleaner and compressed air, cleaned up the female connector and male pins then returned the unit to the SEC.

The idle climbs of it's own volition after sitting at idle a minute or two.  When it hit 1,000 rpm, I unplugged the idle valve connector and the idle raced to 1500 or so, returning the connector drops the idle back to 750 or so and then the steady climb commences once again.

I checked all electrical connections and sensors on the engine.  I checked all of the vacuum lines and their connections on the engine.  I checked the mechanical linkage and performed the inspection and measurement tests from the manual.  All linkages are smooth and it's working as prescribed by MB.

Now my SEC is an 83 with a vacuum advance diaphragm on the side of the distributor.  This vacuum line when removed at idle drops my rpms to 650-700 or so where they rightfully should be.  Returning this vacuum advance line starts the steady climb once again of the idle to about 1100-1200 rpm tops.

I suspect this is my problem but, do not know the process to identify what is causing the advance to operate at idle.  Any thoughts or ideas are welcome.  Again this is an 83 380 motor.

Thanks to Mike Ramay for giving me the details on the air valve this AM by phone.

Dick
  ----- Original Message ----- 
  From: Mike R. 
  To: 'Mercedes Coupes Mailing Lists' 
  Sent: Saturday, August 20, 2005 10:55 AM
  Subject: RE: [W126 Coupe] Intermittant high idle question


  Dick,

  High probability that you have the broken wire inside the idle air valve. I know how to fix that and can tell you how to disassemble that $250 part and fix it for $5. Give me a call!!

   

  Later,

  Mike R.

  (702) 494-8056


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  From: mbcoupes-bounces at mbcoupes.com [mailto:mbcoupes-bounces at mbcoupes.com] On Behalf Of Dick Spellman
  Sent: Friday, August 19, 2005 4:20 PM
  To: mbcoupes at mbcoupes.com
  Subject: [W126 Coupe] Intermittant high idle question

   

  Well here is a subject that has only been explored 15,000 times.  Actually, I just need to know what to use in cleaning the air valve.  I get a racing (1100-1300rpm) at times and if I wait a minute the racing drops to normal idle.  When I pull the air valve connector while the car is racing and move the plug in and out a few times the racing drops to normal idle.

   

  So, I am fairly confident it's this metal cylinder with two black hoses coming off of it at the front of the engine.

   

  Do I just pull this outa there and juice it up with carb cleaner and replace or is there some other method???

   

  Thank you,

   

  Dick



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