function of the EHA valve

[shiko]

hello
h have a mb 300 se model 1986 yesterday i found the plug which geos to the EHA valve unplugged then i replugged it but after i did that i found the car very different there was a very bad acceleration and i feel like not enough fuel reachs te engine
i wnted to know what is the function of this EHA valve

 

[Neebo]

Never heard of an EHA valve ?where is it situated?probably called somthing else?

 

[shiko]

it is the black elictrical part behind the distributer

 

[alexander patie]

the EHA controls the pressure difference between the main system and lower chamber pressure. it is supplied with a variable current from the ecu to perform this function. the lower chamber pressure is around .4 bar lower than main system when the valve is de-energised. changing lower chamber pressure effectively fine tunes the mixture control - the "E" part of KE-JETRONIC. for instance, when coasting on a closed throttle with more than around 1,500 rpm the valve is used to allow lower chamber pressure to rise to be equal to main system, this has the effect of stopping fuel injection on deceleration, saving fuel and cleaning up emissions and throttle response. another example is when the throttle is opened very quickly, lower chamber pressure will drop to say .55 bar below main, this increases fuelling in a similar manner to an accelerator pump on a carburettor engine. the ecu uses signals from throttle plate potentiometer, coolant and air temp sensors, rpm etc to calculate the control current to apply at the EHA. the system is designed to operate in a no voltage situation, if the ecu is unplugged the metering head and idle control work very well in default state, only cold running is badly affected.

 

[shiko]

thank u very much alexander but i wonder if this unplugged EHA valve has a role in my problem since when i leave it for 2 days without starting it starts but after leaving it for 15 minutes it stalls and after trying to start it again for 15 minutes it starts but with a very bad idle which after leavin it for about 5 minutes goes very good and then the car becomes very good as if there is nothing bad

 

[shiko]

i had recently changed the fuel pump and the fuel filter and cheked for injctors and for the coil

 

[alibally]

EHA = electrohydralic actuator?