Ok i have a 1999 hyundai accent wont start changed fuel pump and it started ran very bad very! turned it off wouldnt start back up again checked spark plugs no spark and no power going to fuel pump we are stumped anyone have a clue how to get to start?????

wouldnt start before all that or just after, (hummmmmmm)
wont crank or cranks robustly but wont start.
check fuses yet?

when you turn on switch u should hear fuel pump kick on for few seconds if no sound check for power at connection that connects to sending unit. you have to have someone turn switch to see if light tester lights up for first 2 to 3 seconds. If you have power to that point problems in a bad fuel pump.

Check your solenoid

if the car will not take gas at the pump and spills out when trying check the hose that goes from filler tube to the charcole canister it will be full of charcole if so replace canister

Most likely when you found no pressure, the pump isn't working, Was there any gas being pumped out at all? three option here are a bad pump, fuel filter clogged, or your pressure regulator is bad. Disconnect the line right before the filter and have someone turn the engine over to see if gas will pump from here. Then disconnect the other end of the filter and check for gas flow. With the problem getting worse, it just sounds like the pump is on it's way out, which will usually happen this way. Starts a little and gets worse.

yes you should be able to hear the fuel pump run for about 5 seconds once the key is turned to the on pos. check to make sure you have spark. if you do try having someone spray air intake or carb cleaner into intake manifold while you crank. If the truck starts right up for a second (or stays running as you keep spraying) Id say you have a bad fuel pump and id change the sending unit also. (First check the fuel pump fuse and fuel pump relay) GMC and Chevy are nororiously known for having bad fuel pump/sending unit problems. I have prob changed over 60 myself.

replace the crank sensor, when it fails the computor does not see a signal from it an turns off the ignition and fuel pump

Put a fuel pressure guage on the test port on fuel rail. With fuel injected engines if pressure is too high or low car wont start.
Cycle key off to run (not start) you should hear the pump run a few seconds and stop.

ya the fuel pump wont pump with the lines off but the pump is going bad they will work and wont work

ok when the check engine light comes on that usually indicates a engine malfunction...what you can do is go to your local autozone and they can do an OBDII test for free..my bet says it is the cam or crank sensor.. DO NOT SHUT THE CAR OFF AT AUTOZONE..LOL