Do you really need a new lift pump?

[illflem]

Talked with a Cummins mechanic who said there is no problem with zero or negative fuel pressure on a 24 valve at WOT since the VP pump sucks. A 12 valve injection pump doesn't, it needs pressure. Is he full of it? I'm a 12 valver and don't know.

 

[FF1381]

I say YES

I am not a mechanic or anything, but my truck didn't run, and they replaced the pump and it runs now... so i am going with yes

 

[Pit Bull]

My pump was dead "0" psi. Must of been like that for several thousand miles. Ran fine. The only way I knew it did not work was using the test guage. I like having Briars test gauge, so I can keep an eye on the new lift pump. Hopefully if it damaged my injector pump, it will fail before my warranty is up That is another approx. 3 years and 60K miles. I did notice that with the new lift pump that my temp. guage is showing a little lower temp. not much just maybe 5-10 degrees. Does that make sense??

 

[Steve St.Laurent]

Well, D/C themselves is now saying they want to see a minimum of 8 psi at WOT under load and that they changed that spec (10 psi at idle was the previous spec) because of failed injection pumps. Almost all of us know based on our own experiences that they don't replace stuff if it isn't absolutely necessary. In addition - if that was the case (it's ok to go to no or negative pressure) then why do they have a lift pump on the engine at all? JMHO

 

[otis]

My lift pump was completely dead and I didn't seem to notice any difference in the trucks performance but since I had the new pump installed my mileage has increased considerably. I would definitely not take that chance of putting the extra strain on the VP44.

 

[JTBMC]

Thier Dead Wrong

My presures are as follows,

Idle Inlet 10 #

Idle Outlet 8 #

Cruising 75 MPH 8 # in & out of filter

WOT with OD on 4-5 #

WOT with OD off 3-5 #

My fuel mileage has gone for 18 MPG to 14 MPG With 15 #s inlet presure MPG's are up as well as Power.

TJ

Oh Yea I'm on my 3rd pump in 32,000 miles thats quite expensive when you throw an Injector pump in that mix to boot.

TJ

 

[Bigsaint]

I was told the same by a Dodge tech. (neighbor) when my first Mallory failed. No doubt that the VP44 sucks fuel, SPA gauge was reading -11 psi's @ idle. I tried driving and stopped after a 1/4 mile. The truck had zero power and was shuttering real hard under light acceleration. My vote is that he his WRONG.



Scott W.

 

[PAYCHECK]

SUCKS?

Did you say the VP44 sucks?:--)

 

[Bigsaint]

Like that Lewinsky girl :--)



Scott W.

 

[Chipstien]

Read this....

https://www.turbodieselregister.com/forums/showthread.php?threadid=11672



This is a post started by csutton. Opinions on pressures needed for the VP-44 vary from person to person but in this thread mopar-muscle did some flow tests with the factory and a aftermarket pump. The total volume of fuel through the VP-44 didn't go higher than 30 gph regardless of pressure. I feel that moving the lift pump to the back will solve the reliability problem and provide plenty of fuel for lubrication. My . 02 cents worth, save your money.

 

[illflem]

This post seems to condense 15 pages from the above link

Originally posted by Bill Kondolay

For the record,



This whole thing for me started when i read the post about prime loc causing lift pump and the vp44 pump failures.



I found the whole post very interesting, and somewhat confusing, and i must confess i cheated while doing some of my r&d. I hired an engineer to check out the system but wanted to verify his findings before commenting.



I'll be honest with you , i thought this could be a good business opportunity, selling a complete fuel system upgrade.



When the engineer gave me his findings, his findings suported prime loc that pressure has very little meaning without flow.



Obviously i have invested a great amount of money to date in this project, i however believed it would be a good investment at the time.



Much to my chagrin, our testing proved the engineer and prime loc's position.



Based on all our findings, the most effective method is to simply move the oem lift pump closer to the tank and clean up some of the fittings(banjo bolts).



Installing a bigger line to feed the existing oem pump or aftermarket high performance pump at its factory location is a waste of money.



There really was no politically correct way of saying this, i know a lot of people have invested a lot of money.



I am not an expert in fuel systems but i have to conclude as long as your pressure does not drop below 2 psi,you will be ok with the oem system as is.



Next upgrade from there in my opinion would be to move the oem pump closer to the tank.



Keep in mind those of you in cold weather climates, the engine compartment does provide a warm location for your fuel pump to protect the fuel pump from geling.



From there a slightly higher flowing fuel pump located closer to the fuel tank, and once again if cold weather is a factor , the engine compartment is a warmer climate area.



Let me know how you feel about our findings, i am a transmission technician and i am trying to learn about the fuel systems just as you are.



Bill Kondolay

Diesel Transmission Technology

 

[Shooter]

I have autopsied 2 failed lift pumps. They both had a common point of failure. The plastic shaft to pump rotor coupling. Pump stators not scored, vains polished, end plate hone hatch marks still crisp, motors operating.

 

[Pit Bull]

I don't think we even need a lift pump. I think the VP44 was designed to work without a lift pump. The lift pump is just there to make life eaiser on the VP44. Read this on a previous thread from a member that said the CD he recieved from Bosch on the VP44 did not have a lift pump in the design spec's. Now isn't that a hoot

 

[dewdo]

I was heading South on I-5 between Cottage Grove, OR and Eugene, OR when I suddenly lost powe, got high EGT, low boost and heavy black smoke. I thought I had blown the turbo boost hose loose and pulled into the dealer in Cottage Grove, OR. I asked them to check my turbo boost hose and they came back and said my lift pump was bad.



Since it was pouring rain I didn't go to the trouble of removing my VA Box and the service manager told Chrysler I had extensive modification and they voided my warranty. Cost me $600. 00 for a lift pump and it was not the problem. They gave up on troubleshooting and sent me to Cummin's NW in Eugene who found a pack rat nest in the filter box and a sticking exhaust brake. Charged me another $300. and sent me on my way. Trying to get information together to start a small claims suit.



Dewdo in the other Washington

 

[Chipstien]

Fight the Stealer....

dewdo, I feel for you. I hope you win and shove it down their throats. Good luck. Oo.