Fuel Pump running, not flowing fuel to the rail?

[superman22x]

Hi all,
I am sorting out an issue on an LS swap vehicle. This is a 1984 NA 944 with an LS engine. I have been unable to get fuel to the rail. I have a jumper wire to power the pump directly off the battery. I can hear the pump running, but no fuel makes its way up to the rail. The car sat for 7 years with gas in the tank before this. I drained that and put in about 4 gallons of fresh gas. Any thoughts? Is more gas required to get the pump an initial prime?

[dgcantrell]

Nope. I put about 2 gallons in the 88 S I'm working on and no issues priming since it's basically gravity feed to the pump. I'd disconnect the fuel line at the filter and fuel rail and see if you can blow air back through the line first. Also see if you can blow air back though the return line to the tank.

[superman22x]

I'll try blowing air back through the system and see what happens then.

[dgcantrell]

And the obvious check of the filter too..

[superman22x]

Filter is brand new, it's a corvette fuel filter that is the fuel pressure regulator too. It's right after the fuel pump.

[dgcantrell]

And we fuss at Porsche and Audi for making things more complicated than they need to be?

[Techno Duck]

The check valve at the pump may be stuck.

[superman22x]

Originally Posted by dgcantrell

And we fuss at Porsche and Audi for making things more complicated than they need to be?

A returnless fuel system with $35 filter/regulator is about as simple and cheap as it gets.

If the check valve is stuck, that might clear up with blowing air back through. The pump seemed like it was a bit of a pain to remove before, so I'm hoping to avoid that.

[superman22x]

I blew air through the fuel line. Flowed with no restriction. And I forgot to allow for air to escape somewhere, so fuel came back up the fuel line easily. However, the fuel pump still doesn't push any fluid. So I'm not real sure what is going on.

[Jfrahm]

Fuel pump impeller might be spun.

[Backyardbodyman]

Make sure the pump is positioned correct. Try it with an open end and if it flows work your way up the line to filter and regulator. Gas becomes hard like cured varnish when it sits for a long time. If you have no flow out the open end of pump check the hose coming out of the tank and if you get flow you got issues with the pump

[superman22x]

I can flow through if the tank is pressurized, I found out. So nothing is clogged. Pump impeller spun seems like a possibility, since I can hear the pump run, but I don't get any fluid out.

[dwizle81]

Are you sure the pump is pointed te right way?
try cracking a line off the fuel rail if it's a returnless system the air trapped between the pump and the injectors have nowhere to go..

[superman22x]

The pump only has one way right? Banjo bolt on one end, hose barb on the other if I remember right. I need to try removing that banjo bolt and seeing what happens.
Yeah, that's true, I did try running with the fuel line open though, and was unable to get any fuel out.