On 1990-93 models, Volvo uses three types of fuel systems - Bosch LH-Jetronic, Bendix Regina, and Bosch Motronic.
"[Bendix ] Regina and post-1994 cars have only one pump". (my info source is http://www.brickboard.com/FAQ/700-900/FuelSystem.htm#FuelPumpandFIRelayDiagnosticTests)
In the Regina case, that single pump is located in the fuel tank.
Go to Pdftown.com to download a service manual for your car.
Fuel pump is in the fuel tank, the filter, if fitted, is in-line, usually a grey cylinder in the engine compartment.
on my 92 745..one is in the gas tank, the main pump is under the car around where the armrest is
Mounted on top and inside the fuel tank.
Pull the panel down under the glove box and then look toward the firewall. You will see them there. It is very unusual for one to fail on a CI car such as the 81. Fuel pumps are more suspect as the problem
in the fuel tank it is part of the pump you have to turn and click it in.
the fuel filter is located under the car, about even with space between the front and back doors. It is covered by a metal plate that is about 10 inches by 10 inches. bob
two one in each fuel tank
If it is a regina fuel system it has just one pump
One fuel pump for each tank
fuel pressure regulator, or clog due to poor fuel, and check injectors
On my 1994 Volvo 940 Station wagon there are two. My 2.3 is a turbo model, and was told they installed two, one in the tank, accessible behind and under the rear bench seat, and the other mid body next to the fuel filter.