Fuel Delivery Problem

[mistral66]

I've replaced the original fuel tank with a Dansk repro tank, installed a new fuel pump, replaced all fuel hoses, and fitted the delivery and return lines per factory specs. The fuel pump is getting 12V and I can hear the pump once the ignition is switched on. Despite all this, the pump will not delivery fuel. I have tested this pump on a bench with a 12V battery, and fuel delivery to the intake line. Everything works fine on a bench but this pump will not delivery fuel from the fuel tank. The tank has over 3 gallons of fuel. I have no idea what's wrong and would welcome any ideas on what I should do next.

[Benz Dr.]

Try reversing the wires on the pump. It could be running backwards.

[ja17]

These fuel pumps must be gravity feed fuel.  Make sure the pump is mounted low so that fuel can run out of the tank and down to the electric fuel pump. Do not run the fuel supply hose up hill. Quick fix...add more fuel to the tank.

[SchroderHaus]

I recently replaced my tall pump with a short one and couldn't get the new pump to prime at first, and it also wouldn't pump gas.  There is an air bleed screw (or at least that is what i used it for) just to the left of and higher than the inlet fitting.  I removed this screw, air bled out, then bubbles then steady gas and the impeller chamber filled with gas, gravity fed from the tank. I replaced the screw and it worked fine after this putting out 12 psi running and well over 1L in 15 secs.

[BaronYoungman]

Yes you have to prime the pump using the bleeder screw, once it is primed then it creates a suction and will draw from the fuel tank, besides just the gravity.
Bob

[mistral66]

I would never have believed it! I reversed the wires on the pump and that fixed it. Many thanks for the help

[wwheeler]

I did the same thing when I switched from the old tall pump to the new short pump. I believe the wire terminals are in a different position left to right. I connected the wires up to the new pump the way it came off the old pump which is wrong. I then did some electrical tests and discovered I had it reversed. The terminals are marked on the new pump. Not sure about the old tall pump, but I don't think so.