Fuel pump on 1994 caprice not pumping fuel. its a new pump. replaced pigtail harness and relay. checked all fuses and used test light to check wires connecting to fuel pump.

Sounds like a short somewhere in the circuit. If you are able check all wiring coming from the fuel pump for any chafed wires or loose connections check connectors and harnesses for corrosion or loose connection which can cause resistance. also check for any signs of melted or burnt wires or connectors. hope this helps some.

If relay worked when placed in another vehicle you must have a wiring problem. trace wires from fuse block to relay checking for corrosion or short.

Fuel pump energize? Do you have fuel pressure? Check fuel pump fuse.

If not, that is the first thing to sort out. On the firewall you should see a single red wire on a single terminal stud. Below it should be a 6 inch pigtail of wire with a connector- use a jumper wire between the post and the pigtail to test fuel pump- it should come alive. If it does not, the pump or the harness wiring is bad. If it does come alive, see if it comes alive momentarily on the start sequence to prime the fuel line. If it does not- swap the relay for another one for testing and see if that corrects it. If it does not- check the connector for pin condition, but also check the oil pressure switch that grounds that relay once the engine has started. Should be a Tan wire at the relay, may be orange at the switch.

If you do have fuel pressure-
Is the vehicle equipped with an anti theft system? Maybe the key chip itself or the contacts in the ignition switch are worn excessively.

you can't increase voltage , sounds like bad pump or bad ground

Bad fuel pump or bad fuel pump relay, check the relay first that is located on the passenger side of the engine compartment by the windshield. I believe one of then are the fuel pump relay, disconnect the relay and see if the fuse will still blow. If the fuse doesn't blow, replace the fuel pump relay or check the wire harness.
Thank you for using fixya and good luck.

You need to cuss a whole lot more than twice. A voltage meter would be more useful in determining the actual voltage making it to the fuel pump. Something around 12v DC would be appropriate. If you are not getting at least 12v, you need to check the battery, the starter relay, and the fuses to the fuel pump for any corrosion, and make sure you are getting at or near 12v DC.

Fuel Pump RELAY & FUSE CHECKED & DO you Have POWER "TO" Fuel Pump ? ALSO OIL Sending Unit Supplys the GROUND To Fuel Pump , This is A Saftey FEATURE that Shuts Down Fuel If ENGINE Looses OIL PRESSURE . And If This OIL Sending Unit or also Called (OIL PRESSURE SENSOR) << If It FAILS it WILL Cause What Seems Like A Fue Pump Problem But Is Rally Just The Sensor that is BAD. HOPE this Sheds Light on Your Problem !

Check out your oil sending unit, fuel pump and relay, check for power (might be a fuse), the ignition control module (which if you remove it, can be tested for free at AUTO-ZONE), any related wiring, pick-up coil (inside the distributor), and possibly the ignition switch. If I can be any more help just as away.

Do you have a check engine lamp on when you turn the key on with the engine off? If not then you most likely have blown the ecm-b 20 amp fuse in the underhood fuse panel when you cut the wires together at the same time to modify the pigtail connector to the new design

Check and replace pump relay if you have not already.