my 850 glt has been giving me trouble starting, if it sits for a while it takes an excessive amount of cranking for it to start,once it starts it is normal starts right up. i have replaced the fuel pump about 6 months ago. I suspect that the fuel pressure depleats after sitting, anyone know if there is a check valve anywhere in the fuel system ? or has anyone had similar problems . thanks in advance

There is no "check" valve in the 850. Your fuel pressure will decrease rapidly in the first 5 minutes, going to zero in about 10 minutes. That is normal, and the fuel does not run backwards into the tank.
I would replace the fuel filter as a first step. Then clean the throttle body and idle air control lines.
Check the vacuum line from the fuel pressure regulator. If there is any gasoline present, replace the FPR.

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

There is a fuel pressure regulator (FPR) (at the fuel rail if 1993-95) if that's what you're looking for.

I don't have your starting problems, but I find that if I turn the ignition on to the II position and let the pump run a few seconds before trying the starter the car will fire and start nearly instantly instead of after a couple cranks. The pump runs for a good 10 seconds or so when you turn the key to the II position so perhaps you can do that to alleviate the problem.

If the problem really is fuel related (sounds it), the likely culprits are the fuel pump relay, fuel filter or FPR. Volvo suggests replacing the filter at 100K miles, so it's probably due and it's cheap at only around $15-20. The FPR is more expensive. If you hear the pump running every time you turn the key from off to II then the relay is probably good.

-Will
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850 / Mini