89 fuel pressure problem

[krafty]

I just bought a 89 f 150 302 efi , like 4 hours ago.
got it dirt cheap cause we couldn't get it to start.

it ran on ether, and could hear the fuel pump, and line was pressurized when pump was going.

but like a second after the pressure dropped and obviously wouldn't start.

I noticed a small leak on or near the gas tank when I was chaining it down to trailer it home, didn't think that would affect it much.

also when ignition off the tank read half full then when on it went to like half tank over full. idea's there?

but anyways, im a carb guy so im a little out of my league. im thinking maybe if there is a pressure regulator that is just letting it return to the tank?

its been sitting for a while and we put fresh gas in it. he said the last time he tried to start it it fired right up so like a seized valve or something? it was 2 years ago

any input would help.

 

[krafty]

okay so the injectors are not showing signs of leaking, the fuel rail is not leaking, the pressure regulator is in good condition.
if I block the return line the fuel pressure still drops after a second or two.

so... can the fuel back feed through the pump in the frame rail after being pressurized if the pump is bad?