Hello!
My first post into this great forum!

My 1983 280SE has a deceleration valve located just beneath the inlet air filter. The function of the valve is to open during deceleration to bypass airflow from the AFM/control-arm to prevent un-needed fuling during deceleration.

The valve is supposed to be in contact with the two-pin switch located on the throttle linkage just behind the inlet air filter. The valve is also connected to a vacuum switch which is supposed to be operated by the throttle switch.

I have a new vacuum valve on the engine, but the valve dosent open during deceleration (tested with vacuumeter). I have tested the switch and its good.

As i belive it, its not simply enough that the switch registers that the throttle is closed in order to open the vacuum valve and bypass the air from the control arm. If the vacuum valve opens when the engine is idling it would stall since the control arm is bypassed. That means the switch togheter with something else determines if the vacuum solenoid to the deceleration valve should be open or not.

Any suggestions ?

Regards
Odd