I have a customer with some air entrainment issues and I have more investigation yet but I'd like to know: Dead end fuel system: I would like it to have some kind of return to tank like this: Is a hose/banjo readily available? I don't really care for hard line, just including it for completeness.
What's with the steel line connected to the suction fitting on the fuel transfer pump? Seems backwards to me?
Yes, the banjo connectors are redily available.. both in push on and screw on type.. BUT.. you have to know which size you need.. 12mm or 14mm.. just remove the dead end plug and measure the OD. Your also going to need an overflow valve to maintain atleast 20psi in the fuel gallery. I think you might be causing more trouble than solving.. THAT SYSTEM is as simple as they come.. The weak link in the chain is the hand primer.. always leak and suck air.. I switch them out for the Bosch primer.. 99.9% and also the strainer in the banjo bolt under the h primer.. also check your rubber hose connections for air..
Overflow valve meaning like a spring loaded pressure relief valve? Located inside the banjo I presume? Could a drilled orifice suffice? Is there a part readily available? If it is an active valve of some kind would it be providing a constant return to tank? Thanks for the info on the pump and strainer. That is the return from the injectors since this system has no return to tank.
Yes, a constant return aslong as the supply pump, mounted to the side of the inj. pump, can provide enough pressure to overcome the overflow spring pressure.. Depending on the size of your "plug".. they are available in 1.5 or 2.5 bar.. [x14.5-14.7psi] banjo bolt style. AGAIN>> with an orifice type banjo bolt.. your creating a problem.. your STILL relying on the supply pump to hold ALL THE PRESSURE. and they are plastic valves in a steel housing.. and a TIN hand primer w/ a thin rubber gasket.. I REALLY think your air problem layes in your rubber line connections.. What ever you decide.. I have the p#'s available.. TPG
I really don't know what I am going to find. A few weeks ago it had been running off barrels. Now it is on a large tank. The funny thing is there was never any trouble even when they changed the 3' long dip tube from one barrel to another. The motor apparently ate all that air and didn't falter. At that time the relay to the electric lift pump was bad and nobody even knew because the mechanical pump was handling it. Now the electric pump is running. The other funny thing is that the large tank is elevated somewhat so the whole thing should be under gravity. First thing I am going to check is the rock screen in the large tank pickup for gunk. Also going to check for water and then test the ability of the fuel line to flow under gravity.
It turns out the rock screen installed in the large diesel tank was nearly clogged with some kind of gunk. May be a dirty tank. I installed a Racor filter on the tank instead. Time will tell.