Engine/Transmission (1998.5 - 2002) Any problem with high fuel pressure?

[mhenon]

After changing out my entire fuel delivery system ( Vulcan, Glacier, big lines... the works) I'm seeing 24psi at idle and 22psi at WOT.

I've been advised to get it down to 15psi or so(for the VP)... but has anyone ever had a problem with fuel pressure being too high?

Mike

 

[JR2]

Bosch says 14 psi or less, but lots of guys run way more. I would get it down to somewhere near 14 (14-18) and be happy.





You might also ask the guys at Glacier what they think.

 

[NDaniels]

I run at 17psi idle. A friend ran 22 and pump started to leak out the top- took it apart and found a twisted o-ring- that was the original vp also, scary. He is now running about 16 at idle. Nick.

 

[Cummins724]

I get 16. 5 idle & 12psi. wot... . I have the 150 pump & 1/2" lines & I was told by a few mechanics that if you have that kind of flow to fill up a 1/2" line & hold 16. 5 psi. It is more than enough. They said the vp44 was designed to use flow as a means of cooling the pump & pressure shouldn't exceed 18 on a stock pump. Maybe they were right cause @ 16. 5psi... . I've noticed small leaks @ the fuel filter housing & I've had to tighten the fittings.

 

[mhenon]

I run at 17psi idle. A friend ran 22 and pump started to leak out the top- took it apart and found a twisted o-ring- that was the original vp also, scary. He is now running about 16 at idle. Nick.

That's the kind of thing I was wondering about... a real mechanical problem from too high of pressure.

I know Bosch say's 14psi and then you read about guy's running 30+psi with no problems. Just spent a bunch of $$$ to take care of the low pressure crap and now it's up over 20psi and that's not too good either.

Guess I better look into a by-pass.

Mike

 

[PRout]

Not sure if this contributed to killing my VP44 or not, but the week before it died I turned the pressure up to 22 lbs. The next weekend I changed the OEM filter out, and it would not restart (VP dead). Up unitl that point it had been run at about 13psi for its 130k miles pretty much flawlwssly until then. . Im very leary about anything over 16-17 psi to the pump, but some others swear higher pressure is ok. So take your best shot from the info you have available is what I say. I know I have heard from 2 VP44 rebuilders, and the first one said stay under 20, unless your in competition, the other one said keep it at 13. 5 +/- 3 psi. (they both are racers and well known) .

I suspect that anytime you work on the fuel system your introducing air bubbles and/or spikes in pressure that arent good for the pump, and maybe thats why some poeple that dont maintain their truck and just drive it can go forever on theirs. .

After mine poofed out, I added an air bleeder valve at the VP so that now anytime i fiddle with it, can always run the air out the valve back to the tank for a few minutes before subjecting the pump to turbulant fuel. .

Time for someone to chime in and and say they've run 50psi for 300k miles and get 28mpg doing it. . hehe (while towing)

 

[mhenon]

Bosch seems to want 15psi or so in all their pumps. I would just take a quess and say this is the figure they use while setting up a new or re-built pump. Hook it up to a test stand, run 15psi of fuel to the pump and make all appropiate calbrations.

It's hard to make this jive with DC's choice of in-tank pumps that put out little over 5psi. . and that only at idle. WOT goes right to 0psi.

Mike

 

[mhenon]

Here's another strange one. The Bosch pump on my wifes Jetta is very similar to the VP44 (just has 4 lines instead of 6). It works on a dead vacume and sucks all it's fuel through a filter and tank that's got to be 8 feet behind the engine.

We rarely here of problems with this rotory pump. I think the pump on the Cummins is probably right on the ragged edge of being able to supply fuel to such a high torque/HP engine.

Mike