1990 ford E350 460 motorhome

[Vlooken]

Hello ,
I have a motorhome that fuel issues ,so had into shop .
They changed intank sending unit and pump
Changed high pressure pump , new filter , new pressure regulator.
And still will not start . Will fire on starting fluid but dies.
Fuel gauge on rail read less than10 psi .
Jumped pin to continue running pump and pressure will not go above 30 psi .
Turn key off and pressure drops to 0
Have checked computer and all looks good no leaking capacitors.
Am going to try another regulator today, as will not hold pressure.
If not I think maybe the injectors . As the tank was pretty rust when issues started before all this started.
Everything in fuel system is new except the injectors.
Thing is driving me crazy now!

 

[Fellro]

Makes sense if leaking pressure but not actuating. Might pull spark plugs to see if they are wet.

 

[Vlooken]

Changing the regular did not make a difference.
Have ordered be injectors , as this is the only thing in fuel line that has not been changed. I can get it to idle but bit rough , and cannot rev it up at all .