Car wont stay on once it finally does crank

[Streeterboy305]

So I recently put the car back together after replacing the head gaskets. I tried cranking it over, and i did not hear the fuel pump. I found a wire loose from the hot wire behind the alternator. Now I’m getting fuel but car still won’t start, but when it does start it runs for about 5 seconds and then cut off. Any ideas I may be overlooking?

 

[Chuck Leeper]

but when it does start it runs for about 5 seconds and then cut off. Any ideas I may be overlooking?

Fuel pressure stay up once it's running?
Sounds like it may be running off of the prime shot.

 

[TexasT]

was it running before the hg replacement? why were the hg replaced? I'd be looking for a vac leak if it ran before. other wise a compression check is in order along with checking spark as I'm guessing the coil pack was off if both heads were removed. not sure where you are as diagnostics over the interwebz isn't exactly a defined science. as above I'm guessing you could also have a fuel issue. need a gauge on that fuel rail to see where you are.

let us know