still having issues lift pump/ low power/ return banjo fitting

[TFaucette]

well truck is low on power since putting back together from melting piston and all new mods while down and checked lift pump and It held a good 4psi but replaced it anyways with a piston pump and used the Delphi and to my disappointment it doesn't make or hold any more pressure at all over the stock diaphragm which from further research seems pretty normal if you don't go to cummins for the carter brand, well I put the pump on and it automatically pulls the gauge down to -10 so this really confuses me so I get a used return banjo bolt from a buddy of mine and brought it back to normal (5psi idle) and pulls down 1 or two under acceleration. so I guess Monday I will get a new return fitting and try that first. so my questions and concerns are;

1) is 5psi all I can really expect from Delphi piston or is the pump not up to standard? and will it support 400+hp on a ve, I talked to dennis (dennyT) and he suggested a piston style that it would do all a ve could ever ask for but I don't know if that was talking about the cummins/carter not the Delphi



2)another friend is giving me a holley blue that is said to be about 14psi but when I google it, it's only rated for 70gph? (sounds low but I think they rated the low pressure piston in lph so that might be why I think that) will that be all I ever need?



3) I firmly believe I am having some other issue causing the low power (runs good and smooth just weak like stock settings but full power screw is the only adjustment I have and it is right at rpm hang) because lift pressure maintained over 3psi and still feels weeker then before and should have a lot more fuel and air, I am thinking according to my local injection shop that it could be the VE it self (no other possible solution!) that the vanes internally aren't pumping adequate and that at the return fitting I should have about 75psi but I don't have away to check that other then pulling pump and having it looked at. your thoughts?



4)another option I heard is using a p7100 style piston pump and drilling return fitting to regulate lift pressure under 20, has anyone ever had any experience? or would that mess with the required pressures for return?

 

[JLEONARD]

70 gal per hour is huge. You be hard pressed to burn 10 per hour and then only if you had a full load and kept the hammer down. And I doubt a ve pump could process that much anyway. You,d need the p pump for that.
The marine P pumped 370 hp engines can circulate 45 gph but they only burn around 10 at rated. The bulk is returned tothe tank.

 

[fox]

I think you are thinking too hard.

Did you do a flow test on the stock pump? Point is, are you sure the lines and filter in the tank are clear?
( I have seen algea plug things up).
The stock lift pump is fine on those engines.

 

[HHhuntitall]

Stock lift pump "SHOULD" flow plenty of fuel for a VE. A little more pressure certainly won't hurt it. 70gph is not that high, IMO, but plenty for that injection pump. A P-pump needs closer to 110-250 depending on mods, in my experience.



Regardless, I think your problem lies in your pump from what I gather here... . If you were running out of fuel, you'd still feel an initial surge until it uses what is in the filter and falls off. You're not describing that to me, so sounds like you've got a fuel injection issue... . Perhaps a stuck fueling pin on the AFC ramp? Strange that it ran fine until it blew apart and now it won't run well.....



400hp is possible but not that easy with the VE pump... .

 

[Bob Beauchaine]

Cummins had (or still has) a 1st gen piston style lift pump that put a max of 15lbs to the VE. I've been running one for years and it's been on since I hit 394 RWHP in Meridian ID. I can get you the Cummins part numbers if you would like them. You can see my mods in my sig. With those numbers I still see 20 mpg in 50/50 city highway driving.



Since you installed the 366 spring did you set the high speed stop up to about 3200 rpms? How about pump timming - has it been advanced 1/8 towards the head?



Bob

 

[TFaucette]

Cummins had (or still has) a 1st gen piston style lift pump that put a max of 15lbs to the VE. I've been running one for years and it's been on since I hit 394 RWHP in Meridian ID. I can get you the Cummins part numbers if you would like them. You can see my mods in my sig. With those numbers I still see 20 mpg in 50/50 city highway driving.



Since you installed the 366 spring did you set the high speed stop up to about 3200 rpms? How about pump timming - has it been advanced 1/8 towards the head?



Bob

I used the Cummins part numbers at the injection shop to match the Delphi pump they gave me timing is advanced but however it was advanced before