86 TX3 new fuel Pump

[Quinsta]

Hey guys, after my car has been sitting around for the last 8 years, not getting much use, i have got it back on the road and going..!. The other week i had it stop on me in town and would not start again, after towing it home i managed to get the fault back to a dead Fuel Pump.. so i got a replacement, brand new. installed it and away we go.. everything is working good. On the weekend (Saturday)i took it out for a drive but found it hard to start, car turned over for about 3-5 seconds before firing up, didnt think too much of it, then on Sunday i did the same and it took slightly longer to start, ( Whilst running or turning off then back on the car goes fine) its just these long "off" periods that seem to affect it. Im picking that the Fuel rail isnt staying charged while the car is off and the fuel is siphoning back to the tank, the only lines that i took off were the ones around the pump itself, i will be taking the pump back out this weekend to check the lines inside and out, but is there anything else i need to check or should be looking for. Or is there a different problem all together..?
Cheers Dan