DodgeFreak

The search must be down or something....anyways i finally got my gauges hooked up and my fuel pressure was at 4-5 psi and at wot i could suck it down to 0 psi and it would stay there untill i let up to about 1\2 throttle then it'd come back up to 4. this morning i changed the fuel filter and gained about 2 psi so around 5-6. question is whats normal fuel pressure range i know i've read it some where but every time i search the can not display page shows up. basically i need to know what fuel pressure should be at idle and at wot. I read in one of the stickys max fuel pressure at idle supposed to be 18-24 but that seems high. Thanks.

P.s. its a 92 w250 auto not sure whats all been done to the injection pump.

also boost is around 15-18 psi at wot letting it shift thought the gears and egts climb to 975 in the manifold.

Jklawinsky

Obviously 0psi isn't good. Optimal pressure should be around 15 psi but locktite the front seal and you could up to 30. Sucking it down to nothing isn't good but luckily with the VE you can practically run em dry and theyll hold out for a while. Time to be looking into a 2nd gen piston LP.

DodgeFreak

I would do a 2nd gen lp but I don't have the time or the funds right now so I'm going to have to put a stocker in

The_Head

That sounds fairly normal for a stock diaphram lift pump.

jimbo486

That's normal output pressure of the diaphragm lift pump. Range at idle is said to be 3-5psi. An inexpensive replacement/upgrade would be the low pressure piston lift pump. It'll put you in the 15-18psi range at idle so there's no need to tack on the price of a regulator if you were to buy the 2nd gen, high pressure piston lift pump (30psi at idle).

Boost and EGTs are typical of a stock motor.

Lucas1

2nd gen pump is cheap $100
its the fuel pressure regulator where you spend the $$$.
look into a cheap version reg and just do it.

DodgeFreak

so if i ordered a 2nd gen lift pump would it be the low pressure? i tried looking in the sticky for the part numbers i found one but not sure if it was the high pressure or low pressure. they ran a regulator so i wasn't sure. Thanks.

DodgeFreak

ok i just reread the post and it looks to be that the early 2nd gens are higher psi lift pumps than the later? and now i'm confused on the low and high pressure and i wish the search would work is anyone else having problems with it?

jimbo486

The early 2nd gens, '94-'98 12 valves, use the high pressure lift pump. The later 2nd gens, '98.5-'02 24 valves use an in-tank lift pump and yes, it is a lower pressure.

However, the pump you probably want is not found on either of those motors. Unless, you can afford a regulator for the '94-'98 high pressure pump.

If you choose to go with the low pressure pump, here is a list of the parts you'll need for the job, part numbers included. Prices as of August 17, 2009:

(1) Pump | P/N 4988751 | $186.61
(1) Supply Line | P/N 3914753 | $35.74
(2) Supply Line Seals | P/N 3963983 | $1.27 ea.
(2) Gaskets | P/N 3939258 | $2.10 ea.
(1) Spacer | P/N 3914284 | $12.86

Here's a link to the sticky article on the low pressure pump install.

https://www.dieseltruckresource.com/...ll-t93722.html

BILTIT

Can buy it in kit form here:

http://www.dieselautopower.com/produ...ton%20pump.htm

DodgeFreak

Thanks.. if 6 psi ia normal ill run it till I get the 270 + saved. Thanks for the info