8V71N No Fuel Pressure

[ocean spirit]

STB engine wont start. Install fuel gauge at secondary housing and it indicates 0 pressure.Made sure all filters are full of fuel and even gravity filled fuel line to fuel pump.I can visually see through one of the drain holes in the pump housing that the shaft is spinning during cranking.I"m thinking fuel pump failure or am I missing something like a pressure control valve hidden away somewhere .Does anyone know if replacing the fuel pump is pretty straight forward???

Any assistance appreciated
Jim

[Boatsb]

The fuel pumps rarely just fail. Blow the lines out to look for a clog then re bleed the system from the pump back and see if it moves fuel. Pull the pump outlet for that.

[Glory]

You probably don't want to blow through the Racor.

If you have a vacuum gauge, is there any vacuum?

If no vacuum check for void in the fuel system the vacuum system is all of the fuel lines before the pump, check the Racor (or water separator), check the selector valve.

You can also test the pump without removing it. Remove the line from the secondary filter to the pump at the filter end, fill the line with fuel, as best you can, have someone crank the engine, if the fuel is sucked in the pump is likely OK.

If you do remove the pump, after you remove the pump then remove the coupling watch the drive as someone cranks the engine to see if the drive is turning.

[Fanfare]

Years ago I had the shaft from the blower to the fuel pump shear. The pump is just a driven gear and a slave gear, fuel oil is squeezed between them as they mesh into the line to the injectors at about 40-60 psi. Not much stress. Never did figure it out. Good luck.

[Canuck Dennis]

remove a rocker cover, undo one fuel line to injector, spin engine, should prove bad pump, assumes all filters are totally full,had it happen to me this spring, pump read 0 at cranking yet fuel at injector, ended up being bad tune up of injector setting.

[SEVEN]

Something similar happened to me and we narrowed it down to a leak in the reycor. When you crank it over see if the bowl at the bottom has bubbles being sucked in. Not sure if this is it but who knows. Good luck.

[Mike36c]

Depends on how your fuel manifold is set up but maybe try cross feeding fuel from the other side?

[dottieshusband]

As said, that pump is very robust and not prone to failure...that said, it is a very poor LIFT pump, and very, very, sensitive to a loss of prime. Use a simple hand pump to PRESSURE PRIME the system at the secondary. I use a fancy pump with a pressure guage, but a very simple gear oil pump from autozone would work just as well. Any air leaks in the system MAY lead to a loss of prime with days and weeks no starts.

[Boatsb]

when I say blow out the lines I mean remove the fittings and clear them catching the crud and fuel. Its a way to see if theres a buildup in one of the feeds. Never blow back tothe racor in fact racors are not made for pressure. they run vaccuum

[Glory]

when I say blow out the lines I mean remove the fittings and clear them catching the crud and fuel. Its a way to see if theres a buildup in one of the feeds. Never blow back tothe racor in fact racors are not made for pressure. they run vaccuum

Just trying to help, it wasn't mentioned and blast into the Racor would be bad, as we know.