piston lift pump info

[rockmike]

Hey guys,wanted to post some info for all.A while back I purched the delphi HFP702 piston lift pump to replace my old diaphram unit.I have a liquid filled Mr gasket 0-16 psi gauge on the back side of my filter head.

Running a new hastings fuel filter Diesel#2 no WMO for this testing.

The delphi unit put out 8psi at idle and ran about 5-6 psi at cruise about 2200 rpms when I stomped on it the gauge would emediatly go to 0 psi...NOT COOL!

So I called up Eric @ The Hungry Diesel.com and he was very helpful and knowledgable.he sold me the genuine Cummins piston lift pump (the 12psi) version.I built my own spacer(same spacer used on both pump test) the spacer measures exactly .250 with both gaskets installed.

The Cummins pump puts out 12.5-13.5 psi @ idle At cruise again about 2200 rpms I get 13.5-14 psi seen it creep up to 15 psi a few times while holding steady @ the 2200 rpm when I stomp on it the lowest ive seen the gauge read is 7-8 psi...exellant!!

Noticeable pep in the throttle too,the extra fuel press,volume helped with out a doubt!

Just wanted to relay some useful info for us guys building these cool ass trucks.Dont waste your $$$ on the delphi pump they are not to the task IMHO the correct pump should do a fine job at supplying the fuel to the IP and make it last much longer I would think.

Thanks Eric.

[RCCUMMINS89]

Good to hear Mike... Thanks for the feedback, really appreciated.

[Diesel Dawg]

Guess thats why the cummins pump costs twice as much! Good to know though. rockmike is your rig stock? mine has the stock inj. with the fuel turned up and I can drag mine down to 21/2-3psi wot with the stock pump. When I go to 5x12s I will probably have to upgrade to the cummins piston pump.

[rockmike]

last night I pulled my trailer over to home depot and got some roofing material,romped on her a lil playin with the new W/M inj. My gauge doesnt have a light so....point: got some miles on this pump now.

This morning warmin her up to drive out to work it was reading 14.5-15 psi idleing and ran 14 psi most of the way down the freeway @70 mph.Theres one big ,long hill I have to pull.I floored it up that hill and watched the gauges the lowest reading I saw was 8.5 and my boost hit about 38 psi with that W/M

After the hill everything was warmed up real nice now and was reading 12.5 psi @70 mph on flat ground.

[rockmike]

Good to hear Mike... Thanks for the feedback, really appreciated.

Your welcome man.

[rockmike]

Guess thats why the cummins pump costs twice as much! Good to know though. rockmike is your rig stock? mine has the stock inj. with the fuel turned up and I can drag mine down to 21/2-3psi wot with the stock pump. When I go to 5x12s I will probably have to upgrade to the cummins piston pump.

Yup,its the real deal! Thats why I posted this info.I couldnt find a thread like this saying Hey! this delphi pump is weak! I can prove this!Dont waste your money,get the cummins with out a doubt!

My trucks setup:hx35,bosch 190 inj,IP turned up,3200 rpm spring,M&H dynamic timing spacer,snow stage 2 W/M kit,4" exhaust,Isspro gauges ,Autometer tach,BHAF mod with smooth intake tube.

[RCCUMMINS89]

Just for a little clarity... this isn't the Cummins low pressure piston lift pump that you can purchase from Cummins.

This is the Cummins high pressure pump thatis modified from The Hungry Diesel to either 12, 15, or 18 psi.

[rockmike]

Thanks Eric,I failed to mention that,partly because I was assuming thats what you had done cause I didnt recognize that part # on the pump and forgot to ask yeah why the differant part #

You nailed it man,the truck loves the pump!

[RCCUMMINS89]

Good to hear, this the exact reason I recommend the 12 psi pump so often.... you never know when a set up is gonna read a tad higher. I expect you are gaining the couple psi from the larger supply tube as well as fresh filter.

[RCCUMMINS89]

The reason we are using the high pressure pump, is because it has a larger diameter piston than the Cummins low pressure pump as well.

Both the Cummins and the Delphi low press. pump have the same diameter piston, the Cummins just has a stronger spring in it.