1986 Pontiac Fiero fuel pump change out

Before you replace the fuel pump do a couple of tests to see if the pump is really bad.
The pump should come on for about 4 seconds to prime the fuel system when you first turn on the key. And it would come out of the line you disconnected from the filter.

But in case the fuel pump relay is bad, a second thing to try is to crank the engine long enough for the oil pressure warning light to go out.
The oil pressure switch has a secondary circuit to supply power to the fuel pump.
So as long as oil pressure is above 7psi, the fuel pump will run. And would come out of the fuel filter line until the oil pressure bleeds off.

Assuming that the fuel pump did not come on from either of these tests, this is how to replace it.

The fuel pump harness is almost dead center along the firewall.
The fuel sending unit wires are in the same connector. So if your fuel gauge is reading correctly, then you would have to assume that your fuel pump wires are connected.

The fuel pump is in the tank and there are no magic tricks. The tank has to be removed.
Jack the car up and put it on jack stands.

Use a floor jack to help support the weight of the fuel tank.
You will need a 13mm deep socket to remove 2 nuts on long threaded bolts that hold band clamps around the tank.
Then 4 13mm bolts that hold a center support in place.

I prefer to disconnect the hoses after the tank is away from the car, it gives me more room to work, and allows the tank to move around if needed.
Remove the heat shield on the firewall. There are 4 screws with 7mm heads.
The hoses have a combination of a couple of spring loaded clamps, screw clamp with 8mm heads and ¼” heads.

Once the tank is out, replacing the pump is about the same as any electric in-tank pump.

good luck

yes, testing is essential before replacing the fuel pump, it is important to make some test to check if it's nessesary to replace tht fuel pump and to make some other action.

I recently replaced a fiero fuel pump and it was one heck of a project, first of all the car is an 86, therefore everything under there is 23 years old and rusted together, I used a lot of oil on stubborn bolts taking stuff off of there. Second the radiator tubes (copper I believe) run under the sides of the tank, their brackets need to be removed and the tubes pulled out of the way before the tank can come down. Third, the tank is shaped like a \__/ and the walls are shaped like \...../ making it impossible to drop straight down, a lot of wiggling is involved. (the less gas in the tank, the better for this whole operation. Fourth, the clamps on the hoses are hard to get to and don't want to come off, they have to be dealt with after the tank comes down a little way. don't forget to disconnect the wiring beforehand! After the tank is removed It's a relatively simple operation to actually replace the fuel pump and they can be bought pretty cheap online.