What's the reading suppose to be on the low and high on the manifold gauge when the pump is running? What should it be when its off? I'm getting zero on both side. Is this normal? If there is a leak in the system what would it read? I have a 94 EX with R134 system.

 

make sure you opened the valves on the gauge after you hooked it up. if you're reading zero on both sides and you're using the gauge right then your ac is screwed(it has no refrigerant).

download the manual and go to page 903 that should help you troubleshoot
http://hondatech.info/downloads/Auto/Manuals/Civic/