How does a 190E increase idle speed when cold?

[13022]

I wonder if anyone can explain this to me please... How extactly does a 190E increase idle speed when its cold? Is this just done via the aux air valve or is there something else?

My car starts first time, ice or not, but then proceeds to idle at 700rpm. I've replaced the temperature sensors, aux air valve and Overload Protection Relay but haven't solved the mystery yet.

If anyone has any ideas I'd like to hear them

 

[mike65]

Cold Start Valve just by number 3 fuel injector I think. If its not working then it wont run at above the tickover idle I suppose (thats a guess!)

Mike.

 

[13022]

HELP! I'm on the verge of trading in my beautiful black 190E!

I've tried everything I can think of to sort out the slow cold idle:
New Aux Air valve
New Cold Start Valve
New Engine Temperature sensor
New Overload Protection Relay.

It always starts 1st time, but idles at the normal speed of 750 ish even when covered in ice! This makes for really unpleasant cold driving since the engine almost cuts out every time you take your foot off the throttle.

Has anyone else had this? The throttle micro switch seems to work when tested off the vehicle but seems to have no effect if you manually operate it with the engine running... should it (i would have thought so). Does this point to the engine manager losing the plot in its old age?

I would say that if the car would just pick up the revs a bit when cold then it would be operating perfectly... its just that it won't!

As usual... any advice very welcome and much appreciated!

 

[Richard Moakes]

If you consider that the only way that idle speed can be increased is by extra fuel or extra air, then perhaps the EHA (Electro Hydraulic Actuator) or the fuel pump relay, are the next suspects.

I recently had problems with my fuel pump relay, causing stalling on deceleration.

If you don't want to spend any more money, and are handy with a soldering iron, open up that relay and resolder all the joints.

Best of luck,

Richard
1989 W124 300E