Troubleshooting Low Flow, No Flow or Failure to Prime On a GPI/GPRO Fuel Pump

If the flow on your GPI pump is not up to what it should be or it can't prime, here's what you can do.

Flow is low? Can't prime the pump? Here's some things to try to get your GPI pump's flow back up to what it should be.

Before you start, check the pump model by checking the nameplate on the pump. Generally this located on the back of the motor or on top of the pump housing.

Make sure your pump is equipped with a GPI nozzle
Check to see that all threaded connections on pump are properly tightened and free of blockages
Check to see if the pump is receiving enough electrical power and that polarity is correct. If you have an AC fuel pump, have a licensed electrician inspect power wiring
Ensure suction pipe is securely fitted to your pump, is not clogged and is not damaged. Make sure it reaches the bottom of your tank, and check to see if your fuel tank is adequately filled
Inspect the pump's hoses, strainer, bypass poppet and bypass o-ring for clogs, binding, leaks or damage. You can find how-to videos on removing and replacing strainers and poppets in the links below
If the pump motor still doesn't properly run, open the pump and check the rotors, gears and vanes for damage or jams. Turn off the pump and disconnect from power. Remove the pump cover plate and inspect the inside of the pump for any obstructions. If you need to replace a rotor, gear or vane, use the links below to go to the walkthrough on how to do that with your pump type

EZ-8 Series
Clean or replace gears
Clean or replace bypass poppet

G20 Series
Clean or replace gears
Clean or replace bypass poppet

M-Series
Clean or replace gears
Clean or replace bypass poppet

V25 Series
Clean or replace vanes
Clean or replace bypass poppet

PRO20/35 Series
Clean or replace vanes
Clean or replace bypass poppet