Ed, = There is one more=20 thing to think about in your system. Return restriction. If you have a = powerful fuel pump, one that is a bit higher output than the one = intended for=20 the pressure regulator, there may be too much restriction in the = return line=20 to the tank to lower the pressure. The regulator opens the valve, but = the pump=20 overwhelms the ability of the return line to get the fuel back to the=20 tank.
In the old "dribble" style injectors like the old Hilborne = mechanical=20 systems the top end mixture was set by fuel pressure. A return jet to = the tank=20 was sized backward to normal for mixture. A larger jet lowered the = return=20 pressure and leaned the WOT mixture. Obviously the top was made richer = with a=20 smaller jet. You may have a situation where your return line is = like a=20 smaller jet. Since you are showing higher fuel pressure than Buly the = logic=20 still works. Since your pressure isn't extrodinarily high and you = injectors=20 are time rather than pressure based your system would still run fine. = So long=20 as the pressure wasn't so high as to prevent the injectors from = closing the=20 engine would run OK. Hope this might help.
Bill Jepson =

I agree with your assessment, = Bill. I=20 found the specs on the Pressure regulator and they state it flows 8 - = 10.5=20 GPH. I assume that is referring to return flow. Which = brings up=20 the question if my pump puts out 45 GPH at 40 psi it would seem that a = return=20 flow of 10.5 GPH might be inadequate to regulate pressure - but, I am = not=20 certain how much effect on pressure that flow would have. I know = that=20 with no-flow (no pressure regulator) the pressure goes up to 80 psi - = so does=20 the return flow of 10.5 gph represent that required to bring it down = to my=20 nominal 40 psi? Don't know.

Your assessment, plus Rusty's = observation that=20 the pressure regulator might only respond to positive boost pressure = might=20 well be on the money. I do know that the turbo version is simply = the=20 non-reference version with a screw/tube which is connected to manifold = hose,=20 so it might not be responding to low manifold pressures as = expected.

I think the only way to go is to try a = different=20 brand - perhaps one like Bullents that does appear to respond to = different=20 manifold pressure.

OR simply keep on flying as I have for = the past=20 260+ hours {:>)

Appreciate you insight

Ed A

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