So if you have your fuel psi set up running on the test port on the inj pump it self were is it metering the pressure? is it the pressure on the lift pump or is that pressure the vp44 it self is creating? I might have a dieing inj pump or a possible dieing lift pump and I am at my end as its going too the dealer on Thursday for a diagnostic test too see if my gauge is off. My fuel pressures have been normal so I change the apps and it ran for a couple weeks and the surge was back and the fuel filter is only a week old too. Couple time when I was taking off in the morning it seemed like it was not getting fuel so I am suspecting my lift pump but dont want too rule out the inj pump any sudjestions?

 

Lift pump pumps fuel and supplies pressure and fuel volume to IP. That should be what you are measuring at test port. Be careful, the dealer will try and stick you with a intank setup.

 

Its measuring pressure to resistance at that point. What ever your vp44 is using and returning to the tank is the resistance and what your supply pump is delivering is the pressure. What are your pressure readings?

 

No the deal has a do not work on order I told them I refuse the in tank pump if its just my lift pump. I am getting about 12-13psi idling and its not dropping like it used too use too pull down too about 8psi on it hard nothing more nothing less now my psi is only dropping down too 10psi so its one or the other pumps.