Fuel Regulator?1990 420sel
 

the Item in question is mounted on the driver side of the fuel distributor
and has a vacuum line at the rear,as well as large fuel lines that atatch to it.
If it is going out what would be some of the symptoms?
Mine are, it will start and run then shutter and stall,it will not start up for a long time,If you shut the key off and then back on,and let it sit for five min. it will start up,if you try it any sooner it will try to start but will not.:silly: :(just-n-time

A failed regulator will be leaking fuel out of the small vaccum line connection. Otherwise it should be fine. There are a lot of more sensitive complex parts in front of it that will fail well before the regulator. The problems you describe will not be an easy diagnosis online. Way too many variables to say "X" is likely your problem. I'd first verify spark and then begin concentrating on fuel.

fuel system
 

I suppose I will start at the rear, first I have to say this car sat for 2 years
and allot of the fuel system has bean changed.
both fuel pumps and fuel filter, The fuel distribution block,Injectors,fuel gauge sending unit, Electrical components,ovp,fuel relay,All the fuses.:rolleyes:

vacuum ok
 

No gas leak at the vacuum hose thank you for your reply,j-n-t:silly:

Eha?
 

:confused: what dose this unit do? Dose it control the amount of fuel through the distribution block? j-n-t:silly: