My gas hand doesnt move when i put gas in the gas tank

Put the siphon hose in the gas tank of the vehicle and extend it into a gas can to catch the fluid you will drain. Make sure the gas can is lower than the gas tank in the vehicle. The pressure will move the gas into the can.

Some cars,if you put fuel in the tank while the car is running,the gas needle want show the right amount of gas until you cut the car off and then restart it.If it still on full and want move,you will need a fuel pump.

If the problem happened right after you replaced the pump, I would say the sending unit in the tank is not connected to the harness.
You could check the circuit to the gauge at the connector for the tank.

The gas sending unit in the tank is rusted

Fuel level sender needs replacement. I didn't bother replacing it on my old blazer, just watched the mileage for fillups.

the code doesnt refer to gas cap it is just the most common problem associated with PO440 what it means is the tank isnt building pressure can be caused by leak loose vent hosae damaged canister look for loose connections at tank will not be fuel lines only vent

hope this helps give you ideals plz leave a comment and reply if you have more questions

I have a 1989 Park Avenue with the same problem. It's most likely a problem with the float in the fuel tank. Check and clean the wiring and connectors coming from the sending unit in the gas tank. If that doesn't help then you will need have the float and sending unit removed from the tank and replaced.

Sending unit in the gas tank. Although sounds like possible loose connection considering that it did work momentarily

Tank level sensor would be in the fuel tank and it would necessary to remove tank.

If you remove the sending unit in the gas tank, move it manually by hand as u saw done earlier, the gauge on the dash should also move. As long as the sending unit in the tank isn't 'stuck' at the half full level, the gauge should register empty to full as it moves. To be honest, I'm not sure if I would bother taking the sending unit out. 1st, u must be very careful not to blow yourself up when working on the gas tank (no sparks, etc), all u really need to do is fill up your car, see how many miles a tank of gas will go (carry a can of gas with u to see how many miles before u run out). If it's 350 miles, just set the trip gauge to zero every time u fill up, and get gas every 300 miles so u don't run out. If the sending unit moves freely, everything (wiring ) is connected properly, then it probably is the fuel gauge. good luck!