Two lift pumps or one?

[NPloysa]

Well, the new LP is installed. I still want to put a pusher in. Question is, do I keep both, one up front, and add one to frame near the tank, or put only one at the tank?



Would pressures be too high? I like the idea of redundancy, but what happens if one pump dies, would the other be able to pull/push fuel through the dead one? There are so many ideas out there and searched, but never found many answers except for maybe putting in a bypass around each pump. Guess I could just keep a spare LP in my truck and "plug" it into place if it dies. I am betting the rear pusher pump will last longer since it was designed to push rather than pull in the first place.



As far as fuel lines I will be adding new lines from tank to VP, trashing the banjos and getting AN type more than likely.



Thanks a lot!



Nick

 

[KLockliear]

Depends on the system. Some just add another pump, some replace the stock one. Comes down to the pressure though, you want >6psi, WOT. If you have that, you're OK from a fuel delivery standpoint.



We typically recommend bigger fuel lines and fittings (not banjo's) for 350+hp applications, then our pusher kit for trucks over 425hp. Those seem to be the levels where they become necessary.

 

[Gary - K7GLD]

I've used the 2-pump setup since my truck was new - a 7 psi Carter at the tank, and the stocker. Psi is fine under all conditions, and no guage/sensor problems with the Westach setup I run - I really think the 2-pump setup goes a long way towards smoothing fuel delivery impulses to the injection pump.

 

[AHughes]

Two lift pumps

Installed a low pressure 5lbs Carter electric pump just in front of the tank 20,000 miles ago and have the stock pump on the engine drilled out the banjo bolts to 3/16" and just love it. I also installed a Stanadyne pre filter just ahead of the tank (pre-pusher pump) and also an in line ball check valve just ahead of both of them so I could shut off the fuel from the tank should I want to change the filter or pusher pump. I now have 20,000 miles on this setup with a Westach pressure gage I can't bring the pressure down below 18lbs at WOT. The pusher pump primes the stock pump before starting so the stocker doesn't have to pull clear from the tank. I replaced two factory pumps before I installed this setup and I don't think I'll have any problems with pumps any longer. The stanadyne filter setup flows 100 gal per min which I think is plenty and the replacement filters are about $20 bucks and last 15,000 miles also have a water drain on the bottom of them. The low pressure electric pump I think is about $60 retail. I think this will work. The fuel pressure at idle is about 21 lbs. per in. The factory manual suggests that the injector pump has a 30 lb. pop off so I think this will not harm the VP-44. We'll see??? Just what I've come up with that works for me. 98. 5 EDM 65 hp injectors, Edge comp, AFE Intake. DSS, DTT transmission.

 

[NPloysa]

So if I use an OEM pump would I need a pressure regulator or let it pump at it's full potential? The one I just took off is OEM type, and had a bad electrical connection. It still pumps 16-17 psi at idle (as does the one I just put on).



Also, I am not sure if the factory wiring harness was causing the lift pump to not come on or not, so I think I am going to wire it up to my high-idle solenoid switch and use it there, to see if it solves the problem.



Thanks guys, Nick

 

[Gary - K7GLD]

Nick, with a pusher pump, you need to wire a 20 amp or so 12 volt relay ACROSS the power leads currently operating your stock LP - Radio Shack sells them, and they add very little current draw to the computer circuit that actually controls power to the stock LP:



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THEN, use one set of that relay's contacts to isolate the pusher and actually apply power to the added pusher pump - that will allow the pusher to be properly switched on/off like the stocker, and protect the computer from excessive current draw that the pusher creates.



A $4 relay is LOTS better than a $1500 computer!

 

[NPloysa]

Gary, being the non-electrical type, I KNOW what you mean, but I can't picture it. Could you draw a schematic or anyone help me out?



Thanks!



Nick

 

[Gary - K7GLD]

Gary, being the non-electrical type, I KNOW what you mean, but I can't picture it. Could you draw a schematic or anyone help me out?



Thanks!



Nick

Nick, this comes up from time to time, so I'll draw up a schematic and try to get it posted here tomorrow.

 

[R-N-R]

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[NPloysa]

Perfect! I learn by pictures, and that helped! Appreciate it.



Nick

 

[Hohn]

K. I. S. S.



Find one pump that can do what you need and go with it. Unnecessary complexity is a sure path to reduced reliability (exhibit A: 6. 0 PSD)

 

[Cummins Thunder]

K. I. S. S.



Find one pump that can do what you need and go with it. Unnecessary complexity is a sure path to reduced reliability (exhibit A: 6. 0 PSD)

Learned that the hard way more than once.....