The stock fuel pump is a rotary vane pump and you can pump through it, The vanes will retract and be of no consequence. Just because the lift pump dies does not mean instant death for the VP-44. My pump was dead when I bought my truck but I was not aware of it till the P/O mentioned it to me. 5,000 miles later! Replaced the lift pump and still running the original VP 25,000 miles later. 135,000 on the VP. The VP will draw fuel as long as there is no air, once you get air in the line or run out of fuel (same thing) then the VP will not be able to draw from the tank. The pump in the tank is a impeller type of pump which you can also draw through if you want to replace the original pump.

Rick

 

i not quite so sure that is correct about drawling through the tank pump, a friend of a friend put on a FASS and left the in-tank pump in and burnt up the new FASS.

i have 6-8 used lift pumps at work, i will see if of you can push fuel through it today.

 

you can plow air through the not runing lift pump, there is restriction though.

i took one apart and removed the rotor and vanes, then it free airs.

to remove the rotor and vanes, just take the top off and they fall out.

 

When you lift pump dies you have a 15% chance your injection pump will live MAYBE? but the strain you put on IP is huge. Your fuel is the lubricant for your pump just as oil is for you engine 2+2= dead

 

good to know, thanks

 

You can not compare high pressure air to normal fuel flow at 15 lbs. You are trying to move 90 CFM of air at 120 lbs. through, of coarse you will have resistance. Try regulating the air down to 15 lbs. and see what happens. Just about any pump except a positive displacement pump will bypass. Positive displacement pumps are used for high pressure applications, hydraulic, engine oil pumps, pressure washers.

Rick

 

i dont care what the math is, i would not push fuel through a dead not running lift pump. that's crazy and asking for more trouble.

 

He asked if it could be done and I gave him the answer. I am basing this on 40 years of experience. I am not looking for a fight or argument. I am out of this one.