Engine/Transmission (1998.5 - 2002) Lift Pump Thoughts

[IdaH.O.Train]

Don't ask me why I thought of this, but I did. Does anyone think there is a direct correlation to the rate of LP failures and a truck's body style. In other words, is a QC LWB more likely to have LP problems then let's say a QC SWB?



I ask this because it is my understanding that the LPs are designed to pull fuel from somewhat short distances and the fact that they're pulling fuel from 8 +/- feet, is most likely contributing to their failure. I may be way off base here; however, it seemed to make sense at the time.



It's amazing what the mind does when it wanders.

 

[CFAR]

Lets start a survey of LP failures



I'm on my 3rd Lp



QC Long Bed.



Count as you go

 

[Gary - K7GLD]

Already been suggested a few times - and even greater possibility in my mind, would be the climates where the most failures occur - is it possible the northern US has more failures than the South - maybe near-zero temps thicken fuel and cause early pump failures?



THEN, why is it some guys have little or NO LP problems, yet another goes thru 3 or more pumps in very few miles - is it a geographical phenomena - or maybe exceptionaly dirty/poor fuel in some areas compared to others?



It *would* be interesting to nail down some common thread in these failures - at least those where a single owner has multiple failures...



It does seem as though the same fellows with multiple LP failures also go through more VP-44's as well - is it because of the LP failure - or more directly related to the fuel quality/cleanliness itself?

 

[Ted Constantine]

Is there a difference in the distance traveled with the swb vs lwb qc? I could see a regular cab being a shorter distance but given the two quad cabs are teh same length and the fuel pickup is in the front portion of the tank I would think that the short beds and long beds would have the same legth fuel lines. I am sure someone will tell me if I am wrong Ted

 

[ridgid]

I just replaced my 1st LP. at 22000 mi. It failed on the first trip after installing the fuel pressure gauge.

 

[340Mark]

I'm sure it's been hashed out before, but why isn't it in the tank pushing fuel like a gassser?

 

[bmoeller]

Do the 24v's have filters before the lift pumps or not? If not, maybe that could be part of the problem. Maybe the tolerances in the pump are tighter than the ones used in the 12v's and they don't handle junk as well.

 

[mbrolin]

I dont really feel theres any real need for thought on this subject. After all its evident Dodge didnt do a lot of thinking on the LP I should add that Im on my 3rd pump and 37k miles on the truck. Climate is not extremely cold,filter is always changed every 5k miles. :--) Im over due with the 12k mile LP change. Knock on wood.

 

[illflem]

12 and 24 valves have a screen in the tank. 12 valves have a pretty fine screen in the fuel heater on the suction side of the pump. Gasser Rams have a pump in the tank. Transfer pumps on early fuel injected gassers were prone to failure till it was figured out to put them in the tank for cooling.

Perhaps it's heat killing the pumps???

 

[bombero]

Anyone know what the 2003's with the new injection systems have for a lift pump??

 

[Whitmore]

There are a few known reasons for failure in the 24v L/P



worn rotor or brushes



plastic coupling stripping between the drive motor and the pump



spillback spring and ball sticking partially open or being weak allowing partial flow to just spill back instead of being used.



The best thing you can do to upgrade the system is to get a wireing pigtail and mount the oem pump back by the tank, in as low of position as you can. Larger lines helps too as well as ditching the banjos.



cheers, Kevin

 

[Ncostello]

Any attempt to remedy a stock OEM lift pump will eventually end in failure before your engine is even close to being worn out. You will get more miles out of it but it will eventually wear out and fail. The stock pump is not a correct or durable design for this application. Somehow, someone during the design phase of the ISB didn't give too much concern to the fact these pumps couldn't stand up to continuous duty for 250,000 miles (or equal amounts of hours). They couldn't have. (opinion)



All I can personally do is "try" to make life easier for this pump and hope it lasts longer than it does as assembled at the factory. Whitmores on the right track I think. It looks and performs like a crappy little pump because thats exactly what it is. Must have been the first and cheapest one Cummins could find that matched the design numbers they needed. Cost them too much to design and produce their own... or have one custom built just for this engine I suppose.

 

[Gary - K7GLD]

Personally, I don't see the "weakness" of the LP as any really big deal - as long as it would last at least 60,000 miles or more - that would be 4-5 years for most of us, and the pumps aren't all that expensive or hard to swap out - pretty small weakness, all things considered...



BUT, when they fail FAR more often than that, and perhaps take the VP-44 with them, THAT'S and entirely different story! As already mentioned, about the best you can do is make life as easy for it as possible by various available methods, and INSTALL GUAGES to monitor it regularly - chances are, it will only be a minor nuisance for the vast majority of owners...