i have a 94 ls. ignition and fuel are all stock. wouldnt start (cranked just fine), so i replaced the main relay. that didnt work so i replaced the ignitor. that didnt work so i even replaced the coil, still no luck.
with all these new parts, i cranked it and after a few tries it finally started. It stayed on for about 3 seconds. and during these 3 seconds, it was barely on.
i do have spark.
will this definately be a fuel pump problem?

i do hear it prime before i crank it.

 

yeah happend to my freinds 94 ls... cahnge it out and go from there

 

replace your fuel filter as well.

 

If you hear the pump prime every time, it's most likely not the pump (though it could be working just pumping low pressure) Check your fuel filter (may be clogged/ if you can't blow through it easily it's clogged) Check that you have fuel at the engine. if you have fuel and spark all you need if air and compression. good luck

 

update.
with all the new parts i have added, i checked the pump and it flows fine.]
what else could be the problem?
btw: fuel filter is not cloged

 

FPR? Can you measure fuel pressure?

Next, having good fuel pressure at the rail doesn't guarantee the injectors themselves are OK... Each injector should have +12v from the main relay all the time. The ECU closes the ground side of the circuit to fire each one. Got a DMM so you can check that out?

The idea is; step-by-step you verify what's OK, instead of just throwing more parts at it.