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Hy everybody....i m new here...i m also a big fan of mercedes...i have a w124 e320 made in 1994..i bought the car this year in february from a owner who did not respect it..the problem is:when i start the motor it s cold and i start the i have 800 rpm when the engine get s warmer the turation is going up and stay at 1400rpm...when is on DRIVE stay on 900rpm.i don t know what to do..if you have some ideas thank you.sorry about my english
 

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ok, i'm only familiar with the M103 setup, and other non-benzes. most all fuel injection systems, including the M103, there's a idle control valve, which is a solenoid actuated air valve, that bypasses the throttle body, and a idle microswitch on the throttle. when the microswitch tells the ECU the car is at idle, it watches the RPMs and opens/closes the idle control valve to regulate the idle to 800 rpm or whatever.

cracks in the hoses to the ICV will mess with the magic. *ANY* intake manifold vacuum leaks will mess with this. gummed up throttle that won't return to fully closed will mess with this. munged idle control switch will mess with this. gummed up throttle linkage will mess with this.
 

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Discussion Starter #5
thank you

thanks...i eill look on the wacum...but i have a feling that is something else...i miss the m103...very good and simple engine
 

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The cruise on the HFM driven M104 motors is controlled by the ECU and throttle body.

Being a late W124, make sure all wiring is good and if the original engine wiring harness has already been replaced with non-eco type. Same wiring issue applies to the throttle body.

Vacuum is not involved in cruise operation on these later cars. It is all done electronically.
 
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