90 astro van has 10 second crank time, why?

i have a 90 astro van 4.3, in the morning it take a good 10 second crank time to get it started, but it starts everytime after 10 seconds. it didn't do this a month ago, it had maybe a 1 -2 crank time before starting, wen its hot, and i crank, the first second it seems to catch then lets go, and after about 5-7 seconds of cranking it starts rite up. it never left me stranded and it doesn't bother me too much cause i know its always going to start, but i'm selling the van now and would like to get this fixed. it runs fine when started, just vibrates a bit, but it has been like that for years. what do you think it could be?
it has a new fuel pump, egr, plugs, wires, fuel filter.........

Your fuel pump relay is shot. The reason it takes about a 10 second crank to start is you build up the oil pressure by cranking and once you have reached a certain oil pressure the fuel pump can be feed from your oil pressure switch. The fuel pump relay is located in the engine compartment fuse box.
Hope this helps.

could it be anything else? i recently replaced the fuel pump relay with a new one. and i dont have a fuse box under my hood, its a 1990, my relay is on the right side of the firewall,

Pull out your fuel pump relay and see if the van will start the same way.
If it does, your relay is not getting power or not working properly, or the power from the relay is not getting to your fuel pump. Then your fuel pump would have to wait to get power from you oil pressure switch.
The only other thing I can think of that would cause this is your fuel line is not staying pressurized while sitting and the fuel is draining back to your tank. If you have a Haynes Manual from Canadian tire it might help.
Have you checked all your Fuses?

I'd suggest taking a reading on your fuel pressure. Sounds like a weak pump to me.