When the fuel pump kicks on for its initial 3 seconds to "prime" the system, how much fuel should it spit out?

 

As much as it likes until the pressure regulator stops it
ie: when the pressure builds up to the correct value the regulator turns off the pump , so if one just looked at the output of the pump with no pressure regulator the pump would pump flat out .

Paul .

 

That makes sense, but this one only spit out maybe 3 tablespoonfuls of fuel then stopped.....is it possible the regulator is bad??? I unhooked the line at the engine, and cranked over the motor, it took a long time to get a 1 gallon jug of fuel....

 

As i mentioned it depends on how much is pumped to build up the pressure , if there is no leak-by and it (the fuel rail system) holds up pressure it won't need much pumped to build up the pressure back to the standard pressure which is controlled by the regulator .

The only way to check that pressure is with a gauge , if you think the pump is flaky you'll have to check the flow straight "after" the pump and before the regulator , OR disconnect a pipe after the regulator (which you might have done going by your post) and check the flow at turn on as it should pump continually trying to build up pressure ,.

Checked or replaced the fuel filter yet ? , could be blocked . Paul .