I now have two lift pumps to play with. One is brand new, and the other one has an unknown amount of miles on it, but it still works...would it be possible to install both lift pumps so that one can backup the other one if one fails?
Im thinkin I can just splice into the original lift pump wires and add the second lift pump somewhere in the line?

 

Nobody has tried this before?

 

two will just be twice as much trouble, factory lift pumps are only good for target practice

 

Yeah i figured that, but I dont really have the funds for a FASS and just thought I would experiment with some free parts

 

put a holley blue or black on. check this out

 

I agree that the stock lift pump belongs in the recycle bin but if you want to experiment, you could always put your extra pump on the frame rail by the fuel tank and use it as a pusher pump.

 

Yep, you could use it as a pusher. BD and Bully Dog both make a kit that have an additional pump to push fuel from the tank. This makes it easier on both pumps. The BD uses the Carter pump (same as stock) and the Bully Dog uses a Holley Blue. Many have rigged this up themselves with a pump, wiring, relay,and fuel hose.

Good luck, Matt

 

This is what I kinda had in mind..i figure it would at least take some stress off the main lift pump and maybe make it last a few more miles so I dont have to dish out the money for a new VP44

 

I wouldn't splice the wiring directly into the factory pump wiring, but would draw through a relay from the battery.

 

You can do this but why not just run 1 and toss the other one under the seat?

 

Vulcan makes a great wiring harness to add second pump with relay and
wires direct to battery.

 

I can't find it on Vulcan's website, but here on CumminsDatabase.com, Vulcan has a single/dual relay harness that will run 2 pumps.

My only concern would be having the either pump die and the other having to push or pull fuel thru the dead pump. You would need to "Y" the fuel tank output line and have a seperate feed to each pump location. Then there would not be a concern if a pump croaked.

I have a lift pump on the way out now and am thinking going the dual route. If I decide to not run 2 pumps, I will definately run it as a pusher with the Vulcan kit. More for accessibility than anything else. I just have to come up with a "slush" shield for the winter months here.

Jeff

 

If I'm not mistaken,even after quitting, the factory style lift pumps will flow fuel freely through them with very little restriction.This would explain how the truck will continue to run long after the lift pump dies because the VP44 has enough draw to keep going. The only time you need to worry about "T's" and "Y's" is when you go to a rotary vane style pump that could theoretically stop in the closed position and not allow fuel flow through it. The factory lift pumps I'm told are a diaphragm type.

 

The stock 24v lift pumps are rotary vane type. If the motor, or motor to pump coupling fails, fuel can't be pulled or pushed through the pump. This sometimes happens, however, the vast mojority of the pump failures come from a weakening of the internal pressure bypass. When this goes, fuel pressure will gradually decrease over time. In these failures, because the vane pump is still turning, the VP44 can still suck fuel through the lift pump.

Lift pumps on the 12v are diaphram type.

 

It appears I am mistaken, sorry 'bout that.