A year or more ago, I installed a Holley Blue on my truck. I saw about 13.5 psi for a while and it has been steadily declining. I'm now looking at 10.5 psi at idol and about 9 wot.

I think i've heard that there is a screen that should be removed because it is easily clogged. How can I access that screen or could my pump be on the way out?

 

We have 2% biodiesel here and the pressure typically drops to about 10-11 cold and 11-12 warm. It will go down to 5 at -15 F. Summertime it goes to 13 steady.

Possibly it's time for a rebuild. Get parts from Summit. Also the relief valve may be worn. I use a Blue on my streetrod with gas and it's good for a year or so. I won one in a contest so I didn't even fix last year's.

 

how old is the fuel filter? it just might be getting dirty.
is the gauge mount on the VP side of the filter? this is the better side.

-dkenny

 

^true. Remove the 4 bolts on the bottom of the pump, take the brass screen out and reassemble. In order for these pumps to survive, they need a pre-pump filter....install one before the holley pump. Almost 2yrs w/this setup and constant 18 idle/15wot.

 

Thats reading the pressure at the fuel filter. The fuel filter is clean I changed it about a month ago. I'll try removing the screen and see what happens.

 

the pump might be dying on you

I have destroyed one in my truck..yes destroyed..cracked the magnets..
otherwise I think these are good pumps.

-dkenny

 

Just a thought: When my stock LP went out, I put a Holley blue in place for a little while to see if it worked (it did), as I have several I use for gas applications. I noticed on the stock LP, the vanes inside are at a different angle than the Holley vanes. This may be due to the diesel fuel viscosity, I don't know. But they are different and the blue pump I put in didn't last but a few days (it was old anyway, but a good spare for gas). My feeling is that the diesel fuel puts quite the strain on them and the price difference for a stocker vs. a blue just isn't enough to warrant saving $60. Stock LP ~ $190 from the Cummins dealer. And I never use the screen, instead I plumb it downstream from a filter (gasoline apps). IMO, your's may be wearing out the motor and that's why you are seeing lower psi.

 

that might explain why I had one self destruct..
i was thinking it over heated..

did you notice if the angle was in the same direction as the rotation. just different..say 10 degrees vs 25 degrees..just wondering..

-dkenny

 

The angle of the vanes in the stock pump was like they were leaning back out of rotation I believe. The Holley vanes are straight out perpendicular. Similar designs other than that. Good for gasoline, maybe not so good for diesel fuel.