What type of lift pump pressure do you like to see at wide open throttle?

 

Uhhh Who me?

 

i assumed more was better?
is there a problem with being too high as well?

 

Glacier Diesel Walbro.......16 psi at WOT

 

There might be! My system was running 26psi when first installed and it was strongly recommended to get it down around 15psi or so. Seems the Bosch certified rebuilders use 13.5psi to make final adjustments to their injection pumps (VP44 anyway).
This is all second hand info but I've read this many times. Here's what Blue chip Diesel has to say: "We do not recommend running more than 12-15 PSI as that does NOT help the fuel system in any way. In fact higher pressures could diminish fuel delivery to the rotor and make the truck run worse at high RPM and possibly overheat and damage the fuel bypass solenoid."
You can read the rest here:
http://www.bluechipdiesel.com/howtod...aliftpump.html

Mike

 

Talking to our pump builder here Craig, he said that the only thing too much pressure would affect would be a hard starting situation when they are warm. We build VPs here and what they arent using is just returned to the tank.

 

Walbro 392, idles at 18 drops to 15 at wot.

 

well after you see a couple pop the seal between the case and the pump and fill the engine with fuel you realize that not enough fuel can get back to the tank fast enough. I have had 3 fail.....all running higher fuel pressure numbers.

I have found that anything over 25psi is pretty much a hand grenade, take it up in the 30's and the pin is pulled. I have a lot of pump miles in the 12-15 neck of the woods but all my expierience is that more is only better up to about 15-16psi.

if you have a builder that will replace seals for you for cheap, then you can do your own experiments, I would much rather keep it below 15psi to be safe.

 

FASS HPFP: Idles at 19, runs on the highway at 18, and have never seen below 16. The FASS has been on there since 06/05/05.

 

Mine runs 19 at idle, 16-18 around town and drops as low as 11 under full load. I think this is because my fuel line is 3/8 from the tank to the filter housing and 1/2 inch from the filter housing to the VP44.