SLOW240

After much searching on many sites I have not found an answer to my issue yet, and I don't see a Hilux forum so I figure I would start here.

I've got a 1992 Hilux Surf with a 2.4 Turbo diesel (like the 80's pickups were available with). Everytime I leave the truck parked for a few hours, it won't start unless I hold the pedal to the floor. Even then it won't fire for quite some time, then runs rough for the first few seconds. I have checked glow plugs and such, but this is a fuel issue.

My fuel pump and filter are both new. The pump is all connected properly as far as I can tell, (previous owner installed it) and there are no obvious fuel leaks. I tried leaving it sit with the fuel cap off, no difference. If I pull the outlet line off the primer pump it will squirt fuel when I pump it, but if I put my thumb lightly on it, it doesnt build enough pressure to push my thumb away. The pump doesn't go hard no matter how much I pump it so I have a feeling the primer is failing. I was told to blow through a hose in the reverse of fuel flow to see if the check valve inside is any good. I did this through the filter/primer and no air seems to be escaping.

Where else should I look? I'm starting to run out of ideas at this point.