Don't know the model number of that unit. Plunger type or gear pump type? If it is a gear pump type cap the output of the pump and watch it cycle or use the manual lube button if it has one. DO NOT RUN THE MACHINE WITH IT CAPPED OFF ! Test the pressure at this point. should be about 180 PSI i think. If it's low, take the pump unit apart and clean it. re-assemble and test pressure, if its still low there should be a regulator screw in it to adjust. If the pressure there is ok, you either have:
1. a broken flex line somewhere
2. The lube manifolds are bad and need to be replaced. They are not closing allowing the pump pressure to bypass through them.