I need a little help here i have been having trouble with my truck starting. its a 93 dually i put first a holley ele. fuel pump with a pressure regulator. it worked for a while i am running biodiesel at 100% the holley was a rotery vane pump but the gasket did not last in bio-fuel, so then i went to cummins and bought a piston style pump and installed it with a pressure regulator its not one that has a bypass to return. i set pressure at 10 lbs. this worked for 3 weeks now its not starting the only way it will start is to spray either to it then when it starts it runs fine no misses or anything. it will run all day till i shut it off then it wont start. i have checked the fuel lines(replaced both to tank) i pulled the injectors out and cleaned them. i took off the pressure regulator and it started for a day then it wont start . put regulator back on i dont have a shut down solinoid on it & i put new o rings on the control valve.
when i blead the fuel lines at injectors i got good spray i dont have a guage to check pressure. what am i missing?

 

I would say try to put a guage on it and see what kind of pressure your seeing. Another thing you might want to try is to run at least 1 tank of strait diesel through to eliminate the bio-fuel as the problem. It sounds like its starving for fuel on start up.

 

you need a full tank of clean diesel through the system.

there is a guy here who was runnin waste vegi oil till the temps dropped and it gelled in the whole system.

flush with good diesel and see how it runs.

 

Which piston lift pump did you get? One needs a regulator and the other doesn't.

Like everyone else said, I would run a tank of diesel through and if you still have that problem I would try pumping the lift pump primer first before you start and see if it starts right up or not. It sounds very much like an air leak somewhere in your fuel system.

 

I'm guessing a fuel heater gasket leak. Prolly has the original gasket and has been erroded by the bio. Won't leak under pressure, but will draw air when shut down. Watch the ether if you're grid heaters are functional....

 

Agreed.... I had this problem and it drove me nuts for a month or better before I figured it out...

if your using ether, you need to disconnect the heater grids ASAP

 

i got the 1 that needs a regulator i had a guage on it and it was over 15 psi
i am running a tank of diesel in it now.

 

so are we talking about the gasket that goes on the plug for the fuel heater or where is it at?

 

There are several recent threads, with pictures, discussing the fuel-heater seal and it's replacement.

A quick search should find them.

The seal/gasket in question resides on top of the fuel-heater, which is an inch-thick round plastic gizmo that is immediately above the fuel-filter.

To access the heater seal, the filter mounting stud has to be screwed out.

All filter studs are hollow; some have slots for removal, while others have an Allen-wrench recess; a quick look with a dental mirror will tell you which you have.

 

cool thanks. so this will make it not start i mean even as soon as i shut it down it wont restart.

 

i changed the heater seal and still the same thing