fuel presure help on nameing part

[pwr2tow]

Hi all,

I do not have a service manual yet and need help on a part name and how your lift pump acts.

I read on here once about a fuel line or fuel pump pressure restrictor or valve to hold x amount of pressure in the fuel system, what is the name of this valve.

The reason I'am asking is I finally got my fuel gauge from supplier and installed it. The question is this: When i turn key on to start, the fuel pump ingages for a second and the pressure jumps up but as soon as the pump shuts down the pressure drops to zero. The same thing happens if I bump the starter and the lift pump runs for approximately 15 seconds, as soon as it shuts off the pressure drops to zero. Also idleing the pressure is 9 lbs. and running down the road is 9 lbs. , at Wide open throttle the pressure drops to zero. I was just wondering if the restrictor valve (??) is stuck open and not allowing pressure to build or is my lift pump trash. This could also explain the time my truck started, ran for a few seconds and died.
Thanks, Ron
Ron

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1999, 3500, 6x6, slt, auto, 3. 54, Qd cab, ISB cummins, towing 2001 26RKSS Tahoe 5th wheel, 1999 120hp 1800 bayliner.

 

[Steve St.Laurent]

Your lift pump is dead. The pressure will drop when the pump stops - there's no valve to maintain the pressure in the system, yours is acting normal when you turn the key on and it comes up then goes to 0. What's not normal is 9 psi at idle and 0 WOT. The service manual calls for a minimum spec of 10 psi. This is exactly why I tell people you have to have a gauge that you can monitor while driving down the road, not just sitting at idle. Your case is very close to what mine was except I was at 8 psi - I thought it wasn't that big of a deal because it was only 2 psi under spec. When I got my gauge installed and drove down the road and saw 0 I changed it out right away.



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-Steve St. Laurent - President of the Great Lakes TDR
'98 QC LB (CMNSPWR), 4x4, ISB, 5sp, 4. 10 LSD, TST Powermax3, 275hp RV injectors, Joe Donnelly modifed Sachs Clutch, custom ladder bars, SW fuel pressure gauge, BD exhaust brake, Isspro turbo temp monitor, front Draw-Tite receiver, rear Draw-Tite class V receiver, BFG 285/75R16 AT KO's, (all the common stuff clipped)

 

[pwr2tow]

Thanks Steve for the info. Sorry I didn't get back to you sooner but I was away for the weekend at my grand-daughters birthday. I need the number for the most current lift pump if you have it.
Thanks, Ron

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1999, 3500, 6x6, slt, auto, 3. 54, Qd cab, ISB cummins, towing 2001 26RKSS Tahoe 5th wheel, 1999 120hp 1800 bayliner.