Engine/Transmission (1998.5 - 2002) Stacking Lift pumps can it be done?

[grass hopper]

i just replaced my injector pump and installed a fuel gauge. started the truck and the gauge reads 12 psi. hooked up my trailer and started pulling. the gauge dropped to 3 psi so i turned around and unloaded the trailer. well i picked up a new carter lift pump today from napa and was going to replace the one that i have on there right now. then started thinking about just adding the new one closer to the tank and leaving the stock one (i did replace it about a year ago so it's not all that old along with a new filter) has any one ever done this and if so did it help?



or should i even worry about the pump because 12 psi at ideal and 3 psi towing are the norm? i don't know what they should be. any help would be nice.

 

[JOdell]

Gary I think did this. I remember reading something about it on here once. He has a pusher pump as well as a relocated lift pump. I hope he chimes in with the link or a picture. -Jason

 

[grass hopper]

ya i was thinking about it and i don't think it will make higher PSI readings but it mite keep the 12 psi a constent reading in sted of dropping to 3psi at w. o. t

keep them coming

 

[MikeC]

Dual lift punp

I did that Grasshopper but used a 8psi pump and installed it back near the tank. Worked like a champ. Got it from Jeg's, a carter, about $85. 00.

 

[Larry Willard]

There are a lot of people running that set up here. I have had a 7 psi along with the stock pump for almost 100000 miles now. Bought mine from Summit Racing. It is set using the existing lift pump to trigger a relay to turn it on, run through a fused power supply from battery. I also went to the extreme and put a bypass around the pump by the tank so it could draw fuel if it failed.

Larry

 

[keimmmo]

A relocated factory lift pump with a Vulcan big line kit will also give good pressure without adding an extra pump that can and WILL eventually cause trouble. The pressure of the two pumps are added together... two pumps that produce 15 psi will give 30 psi... too much for the injection pump to handle dependably. Been there.



A 15 psi pump and a 7 psi pump will give 22 psi. A little higher than ideal for the injection pump, but it will probably work for a long time.



Again, the REAL secret to having good fuel pressure that does not drop when you push down on the long and skinny pedal on the right is to remove the restrictions from the fuel system. The factory banjo bolts are TERRIBLE!!! The factory fuel line from the fuel filter to the injection pump in only 1/4 inch ID... TERRIBLE!!! Good straight fittings and big lines will make for more reliable fuel pressure than adding a pusher pump!



Steve Keim

 

[Gary - K7GLD]

A 15 psi pump and a 7 psi pump will give 22 psi. A little higher than ideal for the injection pump, but it will probably work for a long time.

YUP - best setup for me so far, is moving the stock Lift Pump down to the frame, with a Carter 7 psi (Model 4600) just ahead of it. I ended up with a bit over 20 PSI or so at idle, and never below 12 PSI under heaviest RV towing loads with the power mods in my sig.



Both my frame mounted pumps look the same - here's a pic of how they are installed:



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Only changes from that pic is that I have removed the filter seen, since I already have 3 others ahead of it, plus I've added a simple flow operated bypass valve arrangement to both pumps to assure proper fuel flow even if either of the 2 pumps fail - I've gotta get a more up to date pic of the setup... :-laf

 

[grass hopper]

thank all of ya'll for the info. does any one know what a stock replacement carter pump puts out as far as PSI? that is what i have & if its high enuff i will just remove the one that is on the engine and relocate the new one down nere the tank. i like the idea of replacing the fuel line with bigger line that is going to be done for sure. but my only question on doing so is. do i replace all of the line from the tank to the filter or just from the filter to the injector pump. or can some one point me to a pic of how its done.

 

[EricBu12]

Do this as I did...



go ahead and replace the regular pump,



then get a 7# pump by the tank. Tap into the wires to the pump and run them to the rear pump. Plumb bypass pipe with a one-way valve so fuel can be drawn around if pump fails



Take the small "L" hose off the filter, run a hose from the 15# pump to a rass T, one leg goes to the filter, the other leg goes to a mechanically adjustable regulator. one legof this goes to a FP gauge, the return port runs back to the tank or to the inlet of the pusher pump...



I have 15 psi Idle and no less than 13 towing hard uphill.

 

[jeepit]

Eric, Do you have pictures of this. I am a visual guy and do not do good with just narrative. And is there a kit that works with the intank pump and how would I set that up??

 

[EricBu12]

Jeepit,



The rear pump looks like the one in the post above... just imagine a pipe bypass around it with "T" s and elbows... I have a Racor prefilter before this and the return of the regulator goes to this...



The other things are hard to take a picture of with all the wires and hoses and stuff on that side of the engine. I think I might have a few pictures in my gallery somewhere... On my Pocket PC right now and can't do multiple windows... I will see what I can do this weekend on posting some.

 

[keimmmo]

Concerning the big lines, most of us have cut the line just ahead of the fuel tank and left everything from there rearward alone. The big restrictions seem to be the banjo fittings and the tiny fuel line from the filter to the injection pump. A Vulcan kit will give you all you need to do the job.



I run only the factory lift pump relocated to in front of the fuel tank. I too idle at 15 psi and never see anything below 12 psi at sea level. All pressures are lower at high elevation... and I live 6000 ft above sea level!!!



Personally, I like the simplicity of the relocated factory pump and big lines. I carry a spare lift pump that I can change in a few minutes if one fails. Of course, I am on only the second lift pump with 155k miles on the truck, so it has not been a common problem!!!



Steve Keim

 

[jeepit]

Steve, I have the intank pump. Would the big line kit help my situation or would I need another pump to bring up pressure. I currently have 8lbs idle, 6 cruise with the intank...

 

[EricBu12]

I would get a 7# pusher on the frame near the tank for that in-tank pump. then you'd be at 15# and probably good flow.

 

[jeepit]

Eric, Who makes a 7# pump? I have a new in box stock pump. Would like to use it if I can. I could add this in line. Do I just tap into current power lines to intank pump? What about too much pressure? I would be up to 20 -22 lbs.