I have a 85 190e that idles at 1300rpm. i have tried everything that I have seen here on the forum to fix it. The only things that i havent fixed is there isnt a check valve in my power booster vacum line ,and there is a relay misssing in my fuse box (the one that is in the bottom right side) I think its for overcharging. Can either of these things cause it to idle high?

Be more explicit regards 'everything' you have tried.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7

First thing I tried was to check the electronic piece that the throttle linkage stops on when the accelerator isnt pressed. I checked it with a volt meter and when I would press the little button in it would make the circuit complete. Not sure if that is the way you check it but it seemed logical. Then I made sure the linkage wasnt binding and would go all the way down. Then I checked for vacum leaks, loose and disconnected wires, blown fuses etc.. Then I checked the relay that has the regular red fuse in the top, it was fine. Also loosened the throttle cable up to make sure it wasnt holding the throttle open any. I think that was about it may have forgotten something its been a long week. Im sure they have a check valve in the power booster line for a reason but was wondering if that is whats causing my idle to be high. Im going to get a new booster line asap but if its causing my problem then atleast I can quit trying to fix it looking at everything else. Thanks for any help

the idle control valve --it is under the air cleaner and has two hoses attached to it. Disconnect, remove, and clean w/brake cleaner until fluid runs clear ..not dirty. This should do it. Worked for me.

Lata,

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"no one changes..it has always been there"
---Robert Nesta Marley

try backing off the fuel mixture, possible vaccum leak and mixture
set very rich to compensate. if so , idle will be high

Ill try the stuff you have suggested and see what happens. I also wanted to see if a leaking injector would cause idle to be high because I have recently noticed that the fuel pump comes on even when its not running and it has a problem with flooding the first time I start it after it has set a while. Oh and while I was trying to fix the idle problem I found out that the fan will spin both ways with ease so I quess my fan clutch is shot. Any ideas on repairing this anyone? Can I rig it up where it will allways turn or something like that? With all the other problems I have I cant replace the fan clutch right now. Thanks everyone for the info.

found "something with 2 hoses going to it and a adjustment wheel on it, took it off and cleaned it. It also had a electric connector to it. hoses where dry rotted so I temp tape them with electrical tape and put it all back on(very hard to get bottom line hooked back up) Didnt help so I adjusted the wheel on the piece and the idle went down but it started surging up and down and allmost going dead. SO I know I probably shouldnt have but I played with the timing to see if I could get it to smooth out. NO luck. The only good news is that while I was doing all this my fan kicked on full blast , so I guess it isnt broke after all. Need help from my mechanically inclinde friends out there. I really would like to keep this car, I allways wanted a mb but this is getting rediculous.

If any of your idle air or breather hoses are shot, replace them all. As long as there are air leaks, any other troubleshooting will be useless. Check all vacuum lines too, and replace any of the rubber couplers that show aging. All this is detailed in many posts here, as well as more complicated issues when these are resolved.

MB uses lots of rubber, compared to Japanese cars of similar vintage. Be prepared to replace most of it on an '85.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7