I am assuming your engine turns, but does not fire. I have a 1995 MB S420 as well, with 74,000 miles, and it did the same thing, but All I had to do was wait about a minute. It then started, but hesitated a bit until it warmed up completely. So, I simply changed my spark plugs from Bosch Super to Bosch Platinum +4 #4418 and presto, it started running like magic. No hesitation, no problems. How long has it been since you changed your plugs. If they are non platinum, they need to be changed every 30,000 miles. The reason I say Platinum+4 is because I have had these in my other car for over 80,000 miles and I inspect them every year, and they never seem to wear out. I think your plugs are worth a try.
Does anyone know why a 1995 S420 can start kind of like choking and then stalls especially when cold? Then it only starts again in about 15 minutes.
Thanks!