No power to fuel pump or to pump fuse at fuse block

20 AMP is a big fuse, I would say its the fuse to the motor check this web site http://www.beijing-fanyi.com/1990/1990-buick-lesabre-wiring-diagrams

The fuel pump has no fuse, it is power as described below.
The two main fuel pump power feeds involve the ASD (Auto Shut-down Relay) which disables the fuel pump, fuel injectors, ignition coil and Oxygen sensor after the loss of a signal from the distributer. The direct power circuit for the pump travels through the relay from a white fusible link which is located under the hood on the left fender panel, along with the ASD relay. The other power feed for the ASD comes from fuse #13 in the fuse block. There's a lot more involved in the operation and troubleshooting of these circuits. So please make sure your diagnosis is correct before replacing the fuel pump, and yes, you do have to remove the fuel tank

Volkswagen Fox Fuel Pumps are located inside your gas tank; being as liquid gasoline is not combustible, this is the best position for installation. Your car's Volkswagen Fox Fuel Pump is an apparatus that operates to move fuel out of the tank to the motor. Your car's Volkswagen Fox Fuel Pump pressurizes the fuel system to move gas from the fuel tank to the engine.

dose it crank at all ?

The Feol pump/circuit opening relay is located inside the cab on a relay block either behind the glove bosx or the right kick panel, I'll see if I can locate a location diagram and post it in a follow up. In the meantime locate the diagnostic check connector under the hood,it's located near the right fender on a fuse block, open the cover and put a jumper wire between the terminals FP and B+, turn the key on and let me know if this makes the fuel pump run.

The most common problems and easiest to detect are
blocked fuel line (unlikely)
blocked fuel filter (probable)
fuel pump not working (probable)
To check the fuel pump you will need to disconnect the fuel line from the motor and turn the ignition on for a brief period to see if any fuel comes out (get some one to help turn the ignition on as you watch the fuel line). If no fuel comes out check the fuses.
If the fuses are fine you may need a new fuel pump.
fuel filters are not expensive and should be replaced regularly
Good luck i hope this helps.

The pump should have a fuse in the fuse block. You need to check for power in the fuse block and you need to check power to the pump relay.

Sometimes there is a fusible link to the Relay. If you check the connector terminals for power where the Relay plugs in, you can determine if the fusible link has blown. You could have already replaced the bad parts and now need to restore power to the Relay.

do not attempt to take apart fuel dist bad news pull off fuel inlet line spray dist full of carb cleaner try agin let me know has car been setting hey vote for me okl

Fusible links will be under hood off of selonide, you will need test light to check because they will not always be obvious.

My 90 Ranger did that when I put in a cheap relay. It's under the fuse block under the hood.