I have a 1993 Ford F 350, 4x4, dually, crew cab, E4OD. Removed the mechanical fuel pump, had problems, installed a Holley Red 7 PSI max electric fuel pump. At the fuel pump I get 6-6.5 lbs, but at the fuel filter, between the fuel filter and injection pump, I read only 2.5-3 lbs. The truck runs very well, has a Banks Sidewinder turbo system and a Maxilube System for added oil pre lubrication and oil purification. I changed the fuel filter and no change. My question is why the loss of fuel pressure and is it possible to bump up the Holley Red fuel pump to give me more pressure.
Thanks, Tom.

 

seems like you have a restriction somewhere. Do you have all original lines? The metal lines could be kinked somewhere, trace them from the pump to the IP and you might see what i am talking about. I redid all of my lines with 5/16" rubber lines because a few spots in my lines were dented somehow, maybe rocks from roads or debris on the roads, who knows. Hope thats it. Oh did you use a blockoff plate or are you pushing through the mechanical pump? Where is your electric pump located?

 

From the fuel tank to Holley fuel pump ( old mechanical pump removed and block off plate installed) to Racor 500 (marine fuel filter with 30 micron filterelement), through Racor thento OEM fuel filter assembly, then to injection pump. I thought that the filter here might have been clogged but after installing a new one the same thing happened, 2.5-3.5 PSI. I can understand that there might be a minor loss, but this seems to be too much. There are no kinks in the lines. What do you think now? Thanks, Tom

 

not sure bro, are both filter elements new? Wonder if you bypass them if you get the 6psi back? Id think the pump should apply the right pressure but with dual filter setup it might be too much? Is the pump back by the tank on the frame rail or where is it?

 

The Holley fuel pump is located about a foot away from the original mechanical fuel pump. If I were to run the fuel line from the electric pump directly to the injection pump then the pressure would be the same as at the pump. Does the fuel filter housin, have within it, any type of restriction that is designed to reduce the fuel pressure for some reason? Thanks, Tom.

 

I would try bypassing the added filter and see what happens. I'd never bypass all filters and go directly to the IP, some protection in there is a necessity.

 

are you getting the 2.5-3.5 lbs running, or shut off??

 

those pumps are not made to pull fuel.they are made to push fuel.
place it back on the frame rail,by the FSV,and let it push the fuel.
she's struggling to to lift the fuel up to the engine.
they make pumps that lift fuel,but your holy isn't one of them.

if you would like an engine bay mounted e-pump designed to pull fuel,contact this guy and tell him you'd like one;
https://www.ford-trucks.com/forums/member.php?u=388490

 

The fuel pressure at the discharge of the pump is 6.0-6.5 lbs, about 4 feet up and through the filters it becomes 2.5-3.5 lbs.at the schrader valve either off or running. The engine runs fine but I'm trying to find out why the lose is occurrring. The fuel filter has been changed, thought that the pressure would be very close to it's dischrge pressure at the pump. Thanks, Tom.