I have followed some of the advise given on this subject and have found an immediate cure to my own problem. I own a 1989 190E 2.6 that recently came up to Ct. from Fla. It spent its entire time in Palm Beach, now once in Ct., I have discovered a hard starting problem when cold. Once the car has been started and the engine is warm, there is no problem experienced, it starts with ease.
After reading many similar problems on this site, I went to the OVP relay and pulled it from behind the battery. The relay has two red 10 amp fuses pluged in to the top of the relay. I discovered that one of them was blown and changed it, replacing the relay. Well, the problem was solved. The car started immediately when cold and runs great. Good advise at a minimal cost. Thanks to all that have placed input into this foram. Marty V.