powerwagon440

i have a problem with my 93 driving down the road it just quits like its not getting any fuel anymore. and on start ups it chugs like it is not getting fuel then u rev it up a bit and it comes out of it! i was looking at maybe the lift pump was not working properly? could the check valves not be working and letting fuel drain back to the tank after shut down and then on start up that is y i get the chug? sounds like its starving for fuel? and a few times now when it just quits on the road i pump the lever on the pump a few times and the truck will fire right up. but when i pump it it has no pressure to it like the chamber is not full! i dont have any fuel coming out of the weep hole as the manual says. just looking for some ideas.

Monty

PW....When mine went bad, it showed no sign of leaking. Top end power was down though. The hand priming lever hadnt worked in over a year. Try to get a fuel psi guage and test the fuel pump. When I finally tested mine..it was 0psi at idle. The VE is made to pull its own fuel in industrial applications, so usually the truck will run with a dead pump.

powerwagon440

well that just bites!!! sounds like the injection pump is the problem then!! cause this is about the same thing that happend when the other injection pump went out!! i was just trying to c if the lift pump was the prob! if u park the truck on a small incline where the engine is pointing down the truck will fire right up with no chug or anything but u park it normally and the other way it will chug and so on! that is y i was askin maybe the lift pump was letting the fuel drain back to the tank? i really dont want to do another injection pump :'(

Monty

On P pump engines..a faulty spring in the overflow valve can cause your symptom when parking on an incline. So, it could possibly be a faulty check valve in the diapraghm transfer pump allowing fuel to drain back to the tank. I am not sure whrere any other check valves are on the pump or fuel system, but I bet they are either in the return system or in the pump itself.

powerwagon440

lookin at the manual there r 2 check valves inside the lift pump.<br> &quot;when the eccentric on the camshaft pushes the lever upward the lever in turn pulls the diaphragm to its extended position. with the lever in the extended position, fuel is drawn into the pump chamber through the inlet check valve. when the pump gathers more fuel in the fuel chamber than the enigne can consume, the outlet check valve is held closed. fuel gathered in the lift pump chamber prevents the diaphragm from relaxing. the lever will continure to move up and down on the shaft connecting it to the diaphragm. however it is prevented from operating the diaphragm until the check valve again opens and the fuel in the pump chamber is expelled. this process continues as long as the engine is running.&quot; <br>This is making it sound like my lift pump is shot?

bigredbrick

Monty and 440, is there a port where one could install a fuel pressure gauge to check it out and keep track of the lift pump? Seems like there's been a few lift pump problems lately.<br>Chris

powerwagon440

ya it sounds like it but im not exactly sure where u tap into it at MONTY will tell us! PW440 bows to monty and awaits his wishdom! ;D

Monty

You can either go pre filter or post filter. For Pre filter, follow the steel line up from the lift pump. It will go into the side of the intake(actually a port on the side of the intake for the fuel filter)and be held with a banjo bolt. Just unscrew the banjo bolt and put your banjo fitting in for the fuel pressure gauge.

Start the truck with the fuel psi gauge hooked up. Observe the reading at idle. Should be around 5-6 psi give + or - 2psi. The gauge will jump back and forth but dont worry, just read your highest reading and record. If you want to get rid of this jumping while testing, just install a needle valve somewhere between the banjo fitting and the fuel psi gauge. Close it off all the way and start the truck. Start opening the needle valve until your reading quits jumping. Next, check your WOT pressure. If your reading is 0psi at WOT, it is time for a new lift pump. A few options for lift pumps are out there including electronic, so if you need one, I will post the info for you.

BTW: I have a permanent 1&quot; el cheapo Spectre gauge screwed into the tapped end of Rods banjo bolt on the pre filter reading. About 7 bucks at Auto Zone. I need to put a needle valve or snubber valve though to take out the psi spikes and fluctuation that a camshaft driven lift pump shows.

Rod sells the tapped head banjo bolts that are perfect for fuel psi gauges if you need one.