New Fuel Pump not Pumping

[smbaird37]

To get to the point, I installed a new mechanical fuel pump that doesn't want to produce any gas. I expected to have some dry cranking so I tried priming the line from the carb side; that didn't seem to help much. Is there a trick I'm missing or do you suppose it's time to check the line to the tank? Any tips appreciated!

I should add, its a '71 1608 - not FI.

[RoyBatty]

I have recently changed out the mechanical pump on the 1600 in my Coupe, only to find the new pump would not move fuel.
I took the diaphragm from the new pump and installed it to the old pump and all worked great.
I believe the check valve assy in the top of the new pump was not working properly. If I recall the new pump was using a spring loaded reed valve for the inlet and outlet check valves and they just weren't doing the job.
The old pump used spring loaded balls in the check valves.
If your pumps have the same bolt pattern and physical appearance, this might be worth a try.

[majicwrench]

This begs the question, why did you change the pump in the first place?? Seems obvious that original was not pumping fuel. Need to check lines/vacuum/pressure before just swapping pump.

There is no trick, should prime just fine with a minute of cranking.

[smbaird37]

Thanks guys. Yes I did suspect the old pump was not 100% and since I was replacing the manifold and carb (with multiple problems), I decided to replace the fuel pump even though it did test with adequate fuel pressure. If I did not miss some trick priming the pump/line, I see two possibilities, new pump is faulty or fuel line is partially and/or intermittently clogged. The Haynes guide does not say much on the fuel lines/tank so if anyone has guidance on checking fuel delivery from tank to fuel pump, my thanks in advance!

[Mrbimmerdude]

I am curious what years do you guys have? I have a 73 and I'm curious if they have both mechanical and electric pumps?.. just a silly question that I will also continue reading more about these cars.

[81SPIDERMATT]

delete ... I am stupid

[sgkent]

make sure the inlet and outlet hoses are correct.

If it doesn't prime, put a fuel hose on the outlet into a 2L pepsi bottle and have someone crank it for a second. That may be enough to get it to pull fuel. There is a small plate and spring that open and close with pressure. I once had a pump fail on my 1973 and replaced it, only to find it was one of those mysterious didn't work while it was on the car but it does now situations. Anything small like a grain of sand can hold that plate open and keep it from working right especially when there is air in the pump.