VERY high idle when starting cold
Thread Starter
Newbie
Joined: Sep 2004
Posts: 4
Likes: 0
From: Oppdal,Norway
VERY high idle when starting cold
I have a 90 230E automatic that have a big problem when i start it from cold.
It goes up to 2500rpm and stays there for a long time.
If i turn off the ignition for a fraction of a second(without the engine stalls),the idle drops to normal instantly.
The workshop have tried to change the idle steppermotor and used several days to examine the problem(without charging me
) with no luck so far. 
Does anyone have the same/similar problem,and a cure for it??
Since it is an auto transmission it almost takes a burnout when i put it in drive
Thanks for ANY suggestions/help
Roger
It goes up to 2500rpm and stays there for a long time.
If i turn off the ignition for a fraction of a second(without the engine stalls),the idle drops to normal instantly.
The workshop have tried to change the idle steppermotor and used several days to examine the problem(without charging me
) with no luck so far. Does anyone have the same/similar problem,and a cure for it??
Since it is an auto transmission it almost takes a burnout when i put it in drive
Thanks for ANY suggestions/help
Roger
Last edited by Bender1; Sep 24, 2004 at 04:01 AM.
Member
Joined: Jun 2004
Posts: 159
Likes: 6
From: BC, Canada
2007 ML350 (M272) 30-509034 & 2008 ML320 CDI
That sounds 100% like your Idle Control Valve....I think the 90's still had one?. All you need to do is remove and clean it with carb cleaner or 99% rubbing alcohol. Allow the cleaner to sit in it and soak...shake it a bit but soak it for 20 min or so then drain and repeat...after put it back in. Clean the tubes that attach to it on either side as well. They as well as the ICV get gummed up. Once you have cleaned it, it will run perfectly. I just did mine on my '89 300TE with the same symptoms but it's perfect now. Once in awhile it needs to be done. My old Saab was the same way. The ICV is right under your air cleaner housing (needs to be removed off the intake). If you cant find it, I can take a pic of it for ya and post it. Cheers
Member
Joined: Nov 2003
Posts: 134
Likes: 0
From: Chicago, IL
1994 E320 Coupe, 1979 500SLC, 2005 E55 - Sold
Hi,I had the same problem. I just disconnected my ICV and drive around. Its a little hard to start when cold, but I manage, just give some gas. I think we need to look into the throttle position microswitch. I did alot of research and that is what Ive found, just havent cleaned it yet. Check it out and let me know what happens. Also,do a search at mercedesshop.com.
Member
Joined: Sep 2003
Posts: 154
Likes: 0
Mercedes Benz
Originally Posted by Bender1
I put a resistor(nut) in the hose going to the isc-motor. Works great!
Roger
Works great!Roger
I like that.-But on the other hand, I agree with spsinha. The TP microswitch has often proved to be the cause for such troubles. But from what I´ve heard, you can´t pruchase it separately. You have to buy the whole throttle body, and that is slightly expensive.
-You can try to clean the contacts of it though, and there is also given the possiblity of slight adjustment by turning it a little bit.
