It's pretty common for new repop floats to leak and sink to the bottom of the tank. To test, take the wire off the sender, with the key on the gauge should go to past full. If so, replace the sender float. There is a ford float that is supposed to be better quality than the repops. Part # COAZ9202B from a ford dealer or mustang parts vendor.I am having a problem with my gas gauge showing any gas. I replaced the sending unit and the gas tank(needed). The gauge still does not register. Given that I have not much trust for repro parts, how cah I test the gauge and sending unit.
Temporarly ground the sender wire to the tank or body. You don't have to disconnect the wire to do this test. The gauge should go to empty. If not, check for a bad connection at the rear harness plug under the dash near the drivers kick panel. If it does go to empty, the sender is bad, if the sender is grounded good.Acardon...My gas guage shows full when I turn on the Key (I hve aded a gound strap and it did nohing...How do I test it. I assume if it shows empty all the time them the float is sunk to the bottom..So how do I test if it shos full with the key on?