2.5 16v idle adjustment and cold start - PeachParts Mercedes-Benz Forum

Uk Merc Man · #1 01-03-2004, 10:37 AM

my 90 2.5 16v is a pig to start in cold weather. have been told to check the cold start valve as this can "gum" up....have searched and searched but cant find it. can someone please explain where the cold start valve is located on a 2.5 16v.

idle adjustment......have searched and searched but no further forward...in real simple terms how do i adjust my idle? its at 1100rpm when warm and i just want to lower it a little.

please help me as these things are doing my head in and i cant find any of the bits to twiddle...

ANY help REALLY appreictaed!!!

thanks

jonnytee · #2 03-09-2004, 01:27 PM

believe this fella lives in the air filter box oppposite end to the inlet....hope this helps

JT

sbourg · #3 03-09-2004, 02:30 PM

A constant high idle is usually an air leak. This will also foil any cold-start enrichment scheme. Find the air leak.

Steve

rbort · #4 03-10-2004, 03:39 PM

Hey Merc man:

I have a euro version 1983 190e, and my cold start valve is installed pretty close to the valve cover about 1/2 way down. It is installed with two 5mm hex bolts, and looks like a cylinder with a fuel line hookup at the top, and a wire connector coming out of it.

The idle speed in my Mercedes is set by a large flathead screw that can be seen looking front the right side of the car just over the valve cover and just under the air cleaner. Turning this screw speeds up or slows down the idle.

Sbourg:

I have adjusted my idle speed with this screw, took the cold start valve out, reconnected it to the fuel line and electrical motor. Tried to start the engine cold and it starts and quits (due to the air leak where the valve sits) but I see no fuel coming out of the cold start valve. I'm thinking mine is not working and it may be it or my temp sensor that makes it operate. I'm going to pick up a couple of parts from the junk yard this weekend to see if it is any better. My symptom is that my car is hard to start when hot and sitting for a while, and that my idle speed is the same regardless hot or cold.

Maybe I have an airleak like you say. How do I find an airleak easily? Is there some trick like hold an incense stick near the lines and see if any smoke gets sucked in somewhere?

-=>Raja.

sbourg · #5 03-10-2004, 04:46 PM

You can test for leaks by just looking for cracks or hardened rubber. As an active test, spraying something non-combustible (e.g. water or rubbing alcohol) at suspect points should cause a change in idle speed, momentarily, at a leak point.

Steve