engine woun't run
 

I have a 1982 928s euro model guy that i bought it from thought that he blew all the valves after checking valves they ware fine after i put everything together i have compression it starts but dose not idle it just dies after it running for 2 seconds please help me out

If it runs for two seconds after you start it and then stops, to me that sounds like a fuel related issue. Isn't there a safety feature with the fuel pump that it only runs for a couple of seconds after starting and then stops, unless the computer gets a signal from the engine that it is actually running. this could be done by crank sensor or such.
The idea is that if engine is not running (after accident or such) that the fuel pump stops delivering fuel.
In your situation it sounds that the computer does not get the signal that the engine is running and shuts down the fuel pump, thus stalling the engine.
Either see if you have a bad connection to a crank sensor or such, or run a temporary hot wire to the fuel pump, and see when starting the engine, if it runs longer then 2 seconds.
If is still does not run, please destroy this message.

Good luck

The magic brain of the early Euro is the WUR, warm up regulator, but I have no clue on the details. My last CIS car was about 30 years ago, but I remember it was REAL fussy about good fuel, so if its been setting I would start with draining out all the bad gas and replacing all the filters etc. Hopefully somebody that knows the Euro will chime in with real answers.