300SL 1991 issues
 

I had to put in a new battery so I did. Now the car will start and run for only 5 seconds or so. I didn't get a manual with the vehicle. I believe it is a security issue. Can any one please help me. It could also be a bad crank position sensor which would not tell the engine that it was turning. When the engine starts it doesn't cough or sputter it run normally. :confused:

I had a roadside call like this once. There is a fuel pump relay very close to the front of the battery, and the owner pulled the battery before I got there. I think he pulled it, then charged the battery and reinstalled it, then wouldn't start.
Long story short is there is a fuse on top of the relay which he bumped, so the fuel pump wouldn't run. It would cough and sputter, but not really run. So might want to just look around for this possiblity. I think the relay was green.

AFAIK there is no immobilizer / security system with ignition cutout on this model year MB.

-J

I think you are right. I also should note that by "bumped" the fuse I mean it actually came out of the relay and was laying somewhere in the battery "pit", I had to cob a fuse out of the service truck to put in the relay to get the owner going. MAN were they happy that's all it was. The guy who did the battery removal/install (boyfriend I think) was really getting the stink-eye from the lady who owned it. I scored him extra points by making some statement like "hell anyone could have done that by mistake".

When the engine starts it doesn't cough or sputter it run normally.