Could this be the solution?

[Bart F-350]

well, My truck is old in years, but (almost) new in mileage, 10234 Mi.

I did test the resistance in the fuel circuit, I measured AFTER the hose, so just before the fuel enters the lift pump, and I had ZERO resistance (or vacuum) at stationary, and non when I had more rev's, I had no Rpm gage when working under the hood, so helas.

Then I measured at the schrader valve, zero pression while stationary, and when I was revving the zero "pression" changed into 10 and more Inches Hg vacuum.

Then I measured again at the connection where the brass valve connects to the fuel retour circuit, that's the after filter circuit,
had a pressure of 2,5 - 2.8 Psig .

running the engine up to 3000 Rpm for two minutes, pressure dropped to -10 Inch/Hg vac.

Then released pedal, Rpm's back to stationary, pressure came up, but did not depass 2 Psig.

 

[Booyah45828]

So before the lift pump - no vacuum or pressure any rpm
Schrader on filter had no pressure and no vacuum at idle. Went to 10inhg vacuum at 3k rpm
Fuel return on filter head had 2-3 psi at idle, -10inhg at 3k rpm after 2 minutes

Do I have this all right?

If so, your lift pump has failed. No vacuum before the pump, and vacuum after shows the pump is not only not keeping up, it's causing a restriction to be created after the pump.

 

[Bart F-350]

Yes, That's what I already thought.
What I still wonder, is if there could be anything in the hardline from the pump to the filterhead and the filterhead itself? (although i had them cleaned when I did the tanks)

maybe a stupid question, but with these lift pumps, how could they fail, and how should that become a restriction? (just for me learning)

For a new one, I saw RA has Carters, would that be a good Idea?
since I heard they could be a bit problematic?

 

[Booyah45828]

There could be, but that should have shown up when you measured for vacuum before the lift pump.

They fail in a number of ways, diaphragm rupture, check valve fail, arm broken off, etc. It doesn't really matter how to be honest. It becomes a restriction because it's still pulling fuel through the pump's check valves. And maybe the pump itself has a clog inside. Or maybe the steel line or fittings between the pump and the filter head has a clog. Pull it off and blow through it to make sure it's free flowing. But aside from a blockage there, your failure is limited solely to the pump.

 

[Booyah45828]

Can't comment on carter vs delphi vs gmb vs spectra vs whoever. I haven't heard anything positive about any of them, so I'd go with whatever has the best cost vs warranty length.

 

[Bart F-350]

would it make sense to continue to do any of the other tests?
Like the at least one Pint in 30 seconds, or Feed IP from a bucket?

at least I don't order a liftpump alone (I don't know if they have a "accompany a toddler alone travel" program with the airline he travels with?




Oh, before there were people writing about the ventilation of the fuel tank, Am I right in that on top of each tank there should be a "anti roll over valve"?
isn't that supposed to ventilate enough, so that a case of fuel tank vacuum shouldn't be able to produce?

You must be registered for see images attach

 

[Old Goat]

Correct, that is the vent, and eliminate any vacuum. The hose attached to it, could get clogged with dirt, mud, debris or a friendly mud dobber. There is the little plastic piece shoved into the end of the hose that keeps it breathing.

Like the hose vent for the Differential also.


Goat

 

[Bart F-350]

I don't know if it really makes a big difference or not, but I guess I'm just busy, why not?
So I did the "capacity test" today, It should be 1 pint in 30 sec. so I thought?
well, warmed up the engine, it had frozen last night but no problem, she started right away!
and when warmed up I connected my modified hose to the Schrader valve, and prepared to do the test.
well, a bit of a desillusion, with the engine running, just a miserable little stream poured out, it hardly covered the bottom of my container.
so defenitley not 1 pint!
big fail!

 

[Bart F-350]

I guess you can see which is the new one?
I do wonder, that long lever, it's different between the old and the new one.
Does it make a difference in it's function?
all other connections are the same.
at this point I stopped anyway, it's raining cat's and dog's over here!

 

[Old Goat]

Both levers work, no difference.
Just make sure the arm is under the Cam
when you install it.

I changed out the steel pipe to the Filter with a piece of 3/8" hose several years ago.

Which ever one you use, fill the Hose/Pipe with fuel first, and make sure the Filter if full. Cut`s down on air in the system.


Goat

 

[Bart F-350]

i have experimented with another system, i've put a suction hose from a e-pump on the schrader valve without the insert and fill-up the pump and filter that way.

 

[Bart F-350]

how can I put this engine (7,3) at TDC?
it seems to be necessary to install the lift pump.

i can't find a description or how to.

 

[Rdnck84_03]

Not needed. Just tip the end of the rod down slightly to make sure you get under the cam.

James

 

[Bart F-350]

I know, but with all the things installed around, (I'm working from above) and working against the pressure of the spring I find it difficult to get the holes lined up and let the bolts grip.
so I prefer to turn the engine to the TDC. No1 cilinder is pass. side towards the radiator, isn't it?

 

[DaveBen]

YES it is.