I would get a different MB specialist. The cold start valve plays absolutely no part in drivability. Its only works while the starter is engaged and even then for no more than 12 seconds at -20deg C.
I agree with benzmac check the overvoltage protection relay (the first place to check is the fuse).
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician
[This message has been edited by stevebfl (edited 04-26-2000).]