[TheRazz]

Howdy all, I've come into possession of a ruff looking 1984 280 SEL AMG Euro. Tho it runs good, whith the exception of the idle. It's former owner live at a much higher elevation than myself, so the car idles at 1500 RPMs insted of the 600-800 RPMs for a car down here. I tried the idle screw ( brought the idle down just barely lowered it 100 RPMs ). I can't seem to locate the MAP sencor, and the O2 Sencor wire was butchered off, so I can't find the other end. ( I'm prity sure that would fix the problem ). Tho any other advice would be much LIKED.

 

[Kingorcus]

Clean your Idle control valve with CARB Cleaner first
if that's doesn't work then change the idle control unit


common problem..

 

[TheRazz]

Where is the idle control valve located? I'm a mechanic, but never workd on GAS Mercedes before. ( Diesel Engines mostly )

 

[Kingorcus]

https://www.autohausaz.com/secure/PartImages/0001411225G.jpg

this is how it looks like

it is located in the center towards the front

disconnect bettery first, disconnect the electric wire, and 2 hoses

soak it in carb cleaner over night...

and check if the throttle linkage is not dirty or stuck as well...

 

[TheRazz]

Ok, can't seem to find the part described, I personaly never seen a fuel injection/plenum set up like this. tho I did find a screw down it idle lowers, i loosen it up it speeds up. It just doesn't tighten any more.

 

[jdc1244]

TheRazz - 3/12/2005 10:51 PM

I personaly never seen a fuel injection/plenum set up like this.

Yes, well you’re going to see a lot of things set up like nothing else before – the idle control valve is the silver cylinder in the yellow circle in the below image.

 

[TheRazz]

It's the DOC straight 6. Maybe that would clear things up. Some of you must be thinking it's the V8.

 

[TheRazz]

I finaly figured it out, it was the timing. I retarded the timing a few degrees and the idle went down. I also looked the the engin type, it's a 126 ( not sure if it's a W ) but it is a 126. I just put silicone patches on the glass headlight cover. had to drill a hole in the bottom of one to drain the water out. I pulled the rear covers off to let the water evaporate the rest out...

 

[jdc1244]

Glad to hear the engine’s running well. The engine type? The engine number is M110, the w126 is the chassis number; although it may be configured a little differently, all MB engines of this era used the same Bosch mechanical fuel injection system.

 

[chriss]

I had this problem and it is a combination of something called an airflow thingy and the ECU but you have to replace both and it is very expensive.

 

[jdc1244]

Mass Airflow Sensor (MAS) and the Idle Control Unit? Yes, the ICU can be expensive.

 

[TheRazz]

The car doesn't have a MAF sensor ( Mass Air Flow ) if the ECU is bad ( electronic Control Unit ) then yes, it is expensive. I found them new aftermarket for about $300 US, but they come with an idle control screw built into it... ponder, as it is my wife doesn't want to shell out $65 US for a balljoint... Wellp, all I can hope for is a firey death taking my son with me, since that the only reason I got the car in the first place. Should the thing let loose in the highway... Heh, that'll learn her!!! LOL