Anyone tried a rotary lift pump?

[AndyL]

I bought a new Holley Blue pump cheap and was thinking of using it as a lift pump. It is a rotary style pump, my thought is it couldn't foam up the fuel since no outside air is available to mix with.

Opinions?

[Billman]

I'm not sure what you mean when you say 'Outside Air'.

Those early Holley's were junk. But I do remember having to put a regulator on the 'Blue' model because it would make 10-14 psi IIRC. The 'Red' version put out 5-6 psi.

Probably better off with original pump.

[AndyL]

I guess no outside air means no air at all to mix with, or no foam possibilities.

I have a new GM lift pump but at WOT it only provides about 1 PSI of pressure. This includes a new fuel filter. Bill Heath says 1 PSI is the absolute lowest you can go without fuel starvation.

I how have a D-Max CAT filter setup from ******** and bet after that install I will have even less fuel pressure. The Holley Blue I have does have an internal bypass, I clipped the spring slightly to bring the pressure down to about 10 PSI max.

I am not sure what generation this Blue is, hopefully being new it is a newer, revisted product.

[gmctd]

Diesel fuel foams when warm because it is trying to go vapor, but is still a little too dense at Baro and ambient temps.

The fuel cannot foam in the pump, as pressure is increased, but does when dumped back into the fuel in the tank - the greater the volume returned, the more foam.
The greater the heat, the more foam.

Passing the returned fuel thru a cooler, bringing it down to ambient from Inj Pump temps will reduce in-tank foaming.

Nothing to worry about unless fuel level is 1/4 tank or less, where excess foaming can uncover pickup sock, resulting in hesitation, bucking, DTC35, and FSD\PMD failure.

[AndyL]

Originally posted by gmctd:
Nothing to worry about unless fuel level is 1/4 tank or less, where excess foaming can uncover pickup sock, resulting in hesitation, bucking, DTC35, and FSD\PMD failure. How could it cause FSD failure?

[gmctd]

Notice I usually include acronym for Pump Mounted Driver, because mine is - full tank of fuel allows in-pump fuel temps of ~140deg, with eng coolant temps of ~200deg.

As that 140deg fuel continues to recombine with less and less fuel in the tank, over-all fuel temp rises, causing inj pump temp to rise.

And pump-mounted FSD temp.

PCM can pull fuel and shut down, based on inj pump fuel temp.

Iirc, the owner's manual addresses this, to maintain more than 1/4 tank of fuel, or some such verbiage.

p.s. Foaming can be a good thing, as the transition from liquid state to gaseous releases some of the heat energy trapped in the fuel.

Still.....I prefer the pre-cooled liquid state.