piston lift pump pressure ?'s

[therabbittree]

Well I converted my truck to the p pump piston lift pump and installed a autometer ultralite II electric fuel pressure gauge. . it reads 55 psi at idle it draws down to say 50 psi driving it hard. . I rechecked the fittings, and bled the air all out and tried different settings on the needle valve setup to adjust it more. . and still 55 -60 psi. . man thats pretty high... I will have to check it with a mech oil pressure gauge tommarrow. . it runs good and has no leaks so far. . any ideas... ? at least when I swap the p pump it will have a load of fuel pressure its its correct. .

thanks,

Deo

 

[CSchafer]

I'm not familiar with the ve's method of regulating pressure but the p-pump has a overflow valve to keep it around 35-40 at 2000rpm. That maybe to much pressure for the ve. Most probobly will say it's way to much I think the max recomended is like 14 but some people have been uping that at higher boost levels to 30 or so but only under boost with a boost referenced bypass regulator. I would get one on it.

 

[DSteimle]

Sounds like you have a second gen lift pump. way to much pressure for the ve. verify your part number.

 

[DSteimle]

sorry, just reread you post. your pressure is right for the p-pump. i've really gotta stop trying to do more than one thing at a time. :-laf

 

[sdstriper]

Well I converted my truck to the p pump piston lift pump and installed a autometer ultralite II electric fuel pressure gauge. . it reads 55 psi at idle it draws down to say 50 psi driving it hard. . I rechecked the fittings, and bled the air all out and tried different settings on the needle valve setup to adjust it more. . and still 55 -60 psi. . man thats pretty high... I will have to check it with a mech oil pressure gauge tommarrow. . it runs good and has no leaks so far. . any ideas... ? at least when I swap the p pump it will have a load of fuel pressure its its correct. .

thanks,

Deo

I recently read some info on Lift Pump ID and Spec's, this is what I have from memory if I remember correctly! Also I would double check any and all of this. There are two types of Lift Pump for the Distributor Injection Pumps (VE), the Diaphram Lift Pump and the Piston Type Low Flow. For the In-Line Injection Pumps there are both Low Flow and High Flow Piston Type. I believe the Low Flow Piston Lift Pumps look identical but have different part numbers and different Pumping Spring Free Lengths. The VE Low Flow Piston Lift Pump has a shorter Pumping Spring Free Length than the In-Line's Low Flow Piston Type Lift Pump. The Max. pressure at the VE Injection Pump is 10psi and the Min. is 3psi, and that is for either type lift pump. The Inline Inj. Pumps have a different spec. that I did not pay attention to. Hope that helps some...

 

[bgilbert]

Shouldn't be long til your truck starts making oil. Swap in the p-pump now, or get the correct lift pump on the engine.

 

[therabbittree]

mummn... I may rig up a regulator or something as the lift pump is gonna stay for th e p pump in the spring... . and ideas on what regulator to use?

making oil by adding diesel from the front seal?...

thanks...

deo

 

[bgilbert]

making oil by adding diesel from the front seal?...

Yep.



I'm using for a regulator Aeromotive A1000 Carbureted Bypass Regulator pn 13204. https://www.jegs.com/webapp/wcs/stores/servlet/category2_10001_10002_19937_-1

 

[CSchafer]

make sure the regulator has a bypass not just the cheap hollys that just plain block off fuel. Summit has a pretty good selection but they are pretty pricey. probobly cheaper to just put the other lift pump back on or get a cheaper electric carburater fuel pump.

 

[PToombs]

Allowed pressure for a VE is 15 psi, no less than 3 at WOT. (2?) I put a piston pump on just before the trip to SOP, 15 psi at idle and 10 at WOT. Sometimes it will get 16 when the engine is cold, but not for long. I have a mechanical gauge on it.

 

[therabbittree]

well I pulled the wide spring out and left the small diameter spring in the lift pump . . now its 20 psi at idle and when reved... and it pulls down to 5 psi or so on a hard pull... . so I "fixed" that one for now. This lift pump had the big wide spring holder and two strings in side one small diameter that held the poppets and awide er one. . both were pretty long. .

thanks,

Deo

 

[dpuckett]

You SHOULD be ok with that- many higher HP VEs run 15- 20psi. But, still keep an eye and nose on the oil.



Daniel

 

[Greenleaf]

There is an adjustable overflow valve for the VE injection pumps similar to the P-Pump overflow valve.



I think it's a trade secret though... ... .

 

[therabbittree]

do you mean the case pressure adjustment on the front of the pump?

 

[Greenleaf]

No. Not THAT valve.

There is an adjustable overflow valve

 

[CSchafer]

VE has an over flow valve also??? Come on Scott do share

 

[bgilbert]

There is an adjustable overflow valve for the VE injection pumps similar to the P-Pump overflow valve.



I think it's a trade secret though... ... .

You betcha. I think our favorite Californian tried one. Not sure whether or not it worked any good for him. Don't dare ask for his R&D:-laf!



Don't worry, if ya got big injectors, I don't think you'll have to worry about much fuel return.



Deo, that's good info to know. I know some have mentioned picking up a 2nd gen piston pump (used or junkyard etc), then buying a rebuild kit for the low pressure 6320 piston pump and swapping out the springs or something. I might have to pick me up a 2nd gen style piston pump at my favorite junkyard and give that a try or at least looking inside one.

 

[Greenleaf]

We are currently discussing this very same topic over in the other Cummins web-site. My point I want to make here is that if you see 5 psi with your current set-up, you'll need to ask yourself a couple of questions;



What lift pump do you have.

What type of fuel system mods have you installed

When and how often do you see 5 psi.



If you see 5 psi or less only when you have your foot to the floor, ask yourself how often do I drive with my foot to the floor to achive 5 psi supply or less. If it's all the time and everyday then you need to take action. If it's 3% of your drive time, then just chill out and enjoy your truck.

 

[sdstriper]

VE Injection Pumps-Low Flow Piston Transfer Pump free length 53. 5mm

(2 7/64)



Inline Pumps-Low Flow Piston Transfer Pump free length 58mm (2 9/32)

 

[Greenleaf]

I measured my P-Pump piston lift Pump No. 3936316 free length at 1 25/32 inch.