Engine/Transmission (1998.5 - 2002) lift pump

[FourBarR]

next week i intend to move the pump back by the tank. i have located a carter pump #p4601hp. it lists it for diesel fuel 100 gph @18 p. s. i. it is the same physical apperence as the o. e. m. pump. it calls for a pressure regulator, i dont see that should be necessary for this application. opions please from those who have relocated the pump. thanks for any advise .

 

[lmills]

I wouldn't worry too much about a regulator. The biggest problem people have experienced is hard starting from high fuel pressure. This can be avoided by drawing your signal from the factory lift pump wiring. It only runs for a second or two when you turn the key, then cuts out till the truck starts. Don't run the pump directly off the wiring, run a power wire back to a relay and use the factory wiring to signal the relay.

 

[WestTN]

run through relay?

I don't think that approach will work. If you use a relay this way it will either pull in and give full pressure or will not pull in at all, giving no pressure.

 

[Mad Bomber]

Re: run through relay?

Originally posted by WestTN

I don't think that approach will work. If you use a relay this way it will either pull in and give full pressure or will not pull in at all, giving no pressure.

I've been running off a relay since 12K it works fine. Can you explain what you mean by this

 

[FourBarR]

lift pump relocation

i will be using the existing wiring. i took the short wiring harness that comes with the o. e. m. pump, i cut it in the middle and spliced in enough wire to go from the original plug at the engine to the new location back at the tank. that way i will not be changing anything. i am making provision in fittings so i can revert to the original pump if this one does not work out. the wiring harness will have the original plugs on both ends so it will fit the pump without any changes. it too bad dc wont fit this problem so we dont have to re-engineer their mistake.

 

[Mad Bomber]

Will the OE wiring handle the greater distance without having problems?In using a relay you put the signal to the relay and then put in better amperage to the pump. Eric

 

[lmills]

The relay method does work and works better than running the line straight back to the pump. It prevents a voltage drop at the pump. There are a couple places selling kits currently that come with the relay and the wiring needed.

 

[Sregorb]

DC has no interest in re-engineering a fix unless they hear from their consumers! I'd love to get all of you on this thread's input on this.



Check out below for more info on this.

https://www.turbodieselregister.com/forums/showthread.php?threadid=75368&perpage=15&pagenumber=1



Brian

 

[juicedcummins]

Running it through a relay works fine. I've run mine this way for about 18 months with no trouble at all. The factory wiring is too light for this pump to start with in the factory location never mind after you move it back.

 

[MikeBeggy]

I just completed moving mine to the frame near the tank. My old pump was averaging about 8 or 10 psi with drops to 1 or 2 psi during acceleration. I used the kit from Practical Solutions which uses a relay and direct battery current for no voltage drop. The kit is 100% good stuff and installed perfectly. The only hassle is locating a metric bango to 3/8 fuel line fittings. I tracked mine to Earls and ordered through Summit. Now, my average idle/driving pressure is 15 to 16 psi and I never see less than 12 or 13 during 5/5 on the Edge comp. Overall, a very worthwhile afternoon.

 

[Loren]

Voltage at the lift pump?

Juicedcummins may be on to something with his comment about the factory wiring being too light.



Is it possible that our lift pump problems are not caused by a bad lift pump design, nor by installing it so far from the fuel tank, but rather by low voltage?



If the wiring is too light for the load, then the lift pump will be running at less than 12 volts. I'm not an electrician, but I do know that electric motors will fail if they are not supplied with sufficient voltage.



Has anyone measured the voltage AT THE PUMP when the lift pump is running? If so, what voltage did you read?



I have a meter and may be able to get a reading from the connection at my relay (that controls my booster pump). If I take the measurements, I'll post the data.



Loren

 

[MikeBeggy]

As a note from my experience, I am on my 3rd pump at 160k and both previous pumps failed due to worn out vanes resulting in more noise and lower output pressure. Niether failure appeared to be electrical.