i adjusted my timing on my stock lo3 to about 5* advanced and sometimes when i start it it'll just quit, and then you have to restart it again, sometimes you have to start it multiple times. what could be the problem?

 

This is a fairly common problem. One issue is that the old C3 ECM doesnt have any variable crank fueling capability. The newer PCMs can adjust their fueling based on how many times the engine has cranked over. They start off with a large shot of fuel to prime the manifold, and then lean out for startup. This really helps get the engine fired up almost immediatly when its cold without any stalls. Also, there is a ramping multiplier for the timing in the ECM. If the ECM ramps the timing in too slowly, the engine will fire, and stall. Adjusting the base timing may make this even worse.

Basically, if the rest of the car is sound, youll have to mess with the cranking AFRs and ramping multipliers to get it to start reasonably well, but this requires that you be able to burn a prom. The other alternative, which is easy, is to crack the throttle open. That will help prevent it from stalling. Also, adjusting the park IAC counts may also help (more min air with less IAC helps the fuel distribution).

Also, did you remember to disconnect the EST before adjusting the timing? Stupid question, but it happens every now and then.