Engine/Transmission (1998.5 - 2002) replaced issolator w/ valve now no reading?????

[Sick Boy]

my issolator went bad on my isspro feul gauge so i put in a valve to replace it ,like many of u guys do. heres the problem no reading on gauge when i crack the valve open i hear the motor change sounds. thought maybe air in the clear tube so i crack the fitting on back of gauge but still noyhing . the trck will shut off if i unhook the line on the gauge, also if i open the valve too much the truck will shut off. got any ideas its a simple hook up dont know why it wont work? help