Stock Fuel Pressure (Lift Pump)

[LesStallings]

The good news is that I finally installed boost and fuel pressure gauges.



The bad news is that idle/cruise fuel pressure is about 8-9 psi and when I nail it the fuel pressure goes to zero by 3,100 RPM.



??Is this normal or am I running on borrowed time with the stock lift pump and 75,000 miles on it??



Should I be looking at FASS or Walbro in the near future?? How soon is soon??



Thanks!

 

[JEnnis]

It's normal.

 

[LesStallings]

It's normal??? Rats.



I might buy a fuel system anyway...



Thanks!

 

[rbattelle]

I agree, sounds normal for a stock lift pump. If you're not spending lots of time at WOT 3100 RPM, I wouldn't necessarily say the pump is on its way out.



Ryan

 

[Doughboy21kd]

i just installed my FP gauge and at WOT i cant pull it under 5 psi... .

 

[Cattletrkr]

The only times my stock LP would hit 0psi was when the filter clogged and just before the in-tank LP went in. Had it up to 3100rpm more than once, never noticed 0psi... might have been busy looking elsewhere though I guess.



I vote not normal. Does the FP come back up after a second or so? A slow response could be a dirty filter.

 

[RDyson]

My EZ/TST stack will pull my pressure down to 1/2# by my gauge. It stays there till I lift. That's on a clean filter.



It is normal if you have a box or two.



Running stock 5# sounds normal at WOT.



I've got a WALBRO on my list too.

 

[RMalone]

My stock pump was 8 or 9psi at idle and 0psi at WOT, with a box. I don't think it's abnormal what you are seeing. If you pull that little turd of a pump off it will be clear why it is normal. I was actually shocked that pump was still working when I went to the GDP walbro setup. The stocker isn't much of a pump and the stock replacement cost is ridiculous, especially now that they stick another junk pump in the tank where you can't readily change it.



Go Walbro, or Fass, or H. blue, or Rasp, or Mitsu, or even a little hand crank transfer pump, but don't go with another stock pump.

 

[gsbrockman]

The bad news is that idle/cruise fuel pressure is about 8-9 psi and when I nail it the fuel pressure goes to zero by 3,100 RPM.

That's typically what I see as well... ... ... . seems as if when I previously ran the EZ (especially on #6) it would easily pull the pressure to zero although the truck never suffered from it. My Juice w/Attitude makes more power and will still drop it to zero, but it starts rising much quicker after a romp from WOT. I'm sure the outside temperature, fuel viscosity, and fuel filter condition ultimately affects the pressure, too.



#ad




Greg