Need Help FAST TBI--Carb

[Ben B.]

Well guys I really need you here....i'm in the middle of swapping a TBI 305 to a carbureted 305, well the new motor runs great, and everything's bolted up....now my buddy and i are just troubleshooting.
The current and probably last problem: Electrical Problem: When you fire the truck up and stop turning the key so it runs, it'll fire up for a second then die, now if i leave the key cranked all the way, the motor will run good...but we all know you can't do that....Any ideas?

 

[clarkjw24]

Did you put a manual fuel pump on it? If not the ecm is prob confused because its not getting info from the tb sensor anymore and is killing the fuel pump.

 

[southernspeed]

Have you hooked up ur HEI feed to a start hot only instaed of start and run hot feed by mistake?

 

[Ben B.]

I have disconnected the Electric fuel pump and the mechanical one is working fine and pumping gas.