Engine/Transmission (1998.5 - 2002) Should I move my lift pump?

[Archive]

I am picking up a new LP on friday and i was thinking of moving it down on the frame right in front of the fuel tank. Is this a good mod to prolong the life of those rotten little pieces of crap or should i just put a pusher on it and hope for the best. I guess i shouldnt be too ****** considering it lasted 32000 miles. Thanks in advance for the advice.

 

[badams1]

Recently I took the fuel tank off my 2001. 5 2500 lwb to install a bottom bung. I was thinking that if I moved the lift pump back there I would have the full advantage of (net pump suction head) available to the pump suction from the tank bottom. After I went through all of that work, and looked real good and hard at the truck, I realized that the lift pump location is only about 4" higher than the center line of the tank. Now thats not a lot of higth to suck up hill. The suction line is 7/16" if I remember right and that is not really that small given the prescribed flow rate even with 275's and an EZ. I still have the option to put the pump back there but really after all was said and done, I decided to leave it in the stock location. The poor quality lift pump is just a weak link in the design that is a disposable, like brake shoes. Pumps like this single stage impeller design do last longer typically when more NPSH is provided if cavitation is suspected, but I am still not convinced that putting it by the tank is going to buy you that much. You still have to suck the fuel almost the same hight from the tank bottom as the fuel level goes down even if the pump is mounted back near the tank. Really, I think from talking to Cummins, that this was well considered when the pump design for this application was spec'ed out. It was designed for that NPSH. Its just a cheap pump and because of that, I run a bed tank to provide the extra NPSH, hoping that will add longivity. I have also installed a fuel return cooler so the fuel vapor pressure stays consistant for viscosity, pump cooling and so lubrication does not suffer on hot days. The fuel can heat up to 190F after an hour or so and that makes a big difference to pump longevity. By the way I hear that the GM trucks have a fuel return cooler. I suspect that the low sulfur fuel is also a culprit. Use a good additive for lubrication. I do all of this and I still carry a new spare lift pump in my tool box. It's a shame ain't it!

 

[Jetson]

The lift pump that has lasted the longest was the original one. Then I moved it by the tank. None of the subsequent pumps have lasted 1/3 as long as the original. I can't say that moving it made any diff at all, except you can hear it run better(or worse).

 

[RADdodge]

Questions...

badams1 – What kind of cooler are you using? Can you kindly give us some details?



I was wondering how many that have added a fuel filter before the pump have had a subsequent failure. Anyone?

 

[badams1]

Fuel cooler and suction filter

I installed a 7 pass cooler from JC Whitney in front of the A/C condensor, about middle position using (4) 3/4" long cut off rubber transmission hose standoff's to ensure isolation from viberation and heat transfer. The cooler came as a kit with pull through button backed fastioners made for this rype of application. It was a perfect sized 5/16" turbulated tubing unit, about 8"x12". I just carefully snaked the 5/16" fuel hose from the cut off SS fuel return tubing to and from the cooler inlet at the bottom and out at the top. I had to unbolt the A/C condensor for access to mount the cooler in the best location. Works great and cost about $30. 00, if I remember correctly. I also installed a huge 20 micron Baldwin BF5813 big rig fuel filter/water seperator with drain valves on each tank suction, to protect the tank switch valve and the lift pump. There is virtually no pressure drop on the big filters and they will seperate out water and contaminates like asphaltines and grit that would distroy the switch valve. I watch the whole show on a Westach 0-30 psig fuel gauge equiped with a snubber and mounted at the lift pump outlet. You know the drill on the gauge installation Genos Garage procedure. I can switch tanks easily to diagnose a fuel filter issue if it should occur. so far so good 15 psig at idle and 10 at full throttle, I am at 17k miles but time will tell. I will change out the disposable Baldwins at 10K mi intervals with the regular fuel filter, sooner if needed. I live in Houston Texas so cold ain't a problem but the cooler could be bypassed or covered for you guys up north. Hey I am trying!

 

[Steve St.Laurent]

According to Federal Mogul (used to be carter) the lift pump specs call for a max of 3 feet from the fuel source.

 

[Daddy]

I'm moving mine this weekend.

 

[Ramafid]

I would move the lift pump. Electric pumps like to push, not pull. I moved my pump and so far so good ( 30 K miles ).

 

[JCyrbok]

whats involved

I've been thinkin about doing this too. My service manual has very generic instructions for removal/intallation in the stock location.



The stock location looks real cramped. Is it a pain to get to, to remove?



What parts/suppiles are needed to complete this? I assume new fuel line and electrical? Connector to splice fuel line at old location? what sizes, etc.



Where is best new location?



Use stock pump or go with a new after market pump?Which one is best for aftermarket. My truck is stock except for Scotty Air II.



Will this screw with warranty considerations, if say the injection pump goes?



Is this worth spending the better part of a day off (I work slow and I'm kinda dumb LOL)



I'm looking for everything that will make my truck run into very HIGH miles as my wife advised this is the last "toy" for quite sometime.



Thanks

J-

 

[Daddy]

I moved mine on Sat. and moved it back to stock on Tues. The noise drove me crazy. Its not that loud but it made a hum that I couldnt take. You couldnt hear it outside of the truck while running but with the windows up in the cab you could definatly hear it. the noise was the same at idle or cruising speed.

 

[Ncostello]

When mounted on the engine, the Cummins noise must mask it. My grandpa's Ford F-150 has a loud intank fuel pump that I could always hear. Its just something that you get used to I suppose. I favor those mounts that portable generator motors sit on to isolate the engine vibration from the frame. Its a thick rubber disk with bolt studs on each side. But the studs are isolated from each other by about 1/2" of soft rubber. Might work for fuel pumps back by the tank. Maybe a little sound insulation mat would help too.



When putting a pump back there, do you have to mount the pump inlet lower than the bottom of the tank to get siphon effect to the pump? I've seen some here mount PE 4200's like this but I was thinking that any kind of fuel pump should be able to overcome a few inches of lift in a short line. I dont agree that just because its an electric pump, it can only push fuel and not create a suction and pull fuel. Most all pumps create a suction and pull in liquid by the reduced pressure created on the inlet side by the impeller. Thats the whole theory behind them. Its just that you want to limit the amount of lift and friction loss that the pump has to overcome to produce a positive pressure on the outlet side and prevent cavitation. At some point the suction the pump creates cant over come height and friction loss in the line. Thus it wont pump. Thats why mounting clost to the fuel source is a good idea. When fire trucks suck water out of a pond or something, its best to get them as close to the water in terms of distance and elevation. But the still work if your 10' above and 20' away from it. Just not as well.