It runs for about 15 seconds then shuts right off. any ideas on what this could be. i just got the motor back from being rebuilt. put it in and started right up. The battery was being over charged so i put in a new altenator in now this happened. HELP!

 

Check the afm, tps and cold start injector system. Something isn't hooked up or adjusted properly.

 

"Starts then shuts off" is the text-book symptom of a problem in the VAF-COR circuit. The key (at "START") turns the fuel pump on, and once air is pulled through the VAF it closes the COR (Circuit Opening Relay) to KEEP the fuel pump running.

It's trivial to diagnose. Jumper FP to B+ on the diagnostic connector to run the fuel pump. If it starts and runs then, you've found the problem.

DO NOT LEAVE THE JUMPER IN as a long term solution. You may die a horrible, fiery death.

 

unplug your cold start injector. if it does not start at all than your injectors are not firing. might be bad wires at the injector plugs.