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High idle, AC related?

575 views 2 replies 2 participants last post by  Jacques405 
#1 · (Edited)
Hello fellow Benz owners.

I installed a tachometer in my 1993 1,8L 190E and it confirmed my impression of high idle : 1300 revs/min...

The strange thing is that if i turn the AC on, it goes back to 750/800...

I did some research on this forum, the ICV does click click when 9V is applied, the hoses are ok.
Today, i wanted to check the Klima relay and : Surprise! There is no AC relay, it has been replaced by a Universal Hella relay 5 pins normally open 4RA 940 010-67...

This is the way it is wired : O empty pin connection :

windscreen
OXOOXO OVPR Calculator Battery
OOXXOO
KPR relay
engine

Car is RHD.

My AC system is not the one you have in the US (with the buttons), i have two levers that travel horizontally, one for the fan, one for the strength of the AC...

Could the missing klima relay be the culprit for my high idling?

Comments greatly appreciated, TIA.
 
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#2 ·
I don't think the AC is your problem. I'd look at linkage and vacuum hoses. At different times of the year, mine can idle between 450 to 750. Mine's mostly around 550. Years back I would spray carb cleaner in different areas to see if it slightly revved up. Be careful, as carb cleaner is highly flammable and could cause a fire. Also be careful that you don't spray it on the cars paint where it might leave a mark. Back in my car shop days....a CO meter would rise if it detected the carb spray.
Just an idea.
 
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