Sounds like it's the pump but you say you can hear it running? Maybe the cross over pipework is disconnected inside the tank?
Either way, check or replacement requires the fuel level to be low enough to check and both floor mounted access plates need to be removed and the locking rings on the tank removed for inspection.
Thread discussion here on things to watch out for when replacing pump
https://www.volvoforums.org.uk/showthread.php?t=271382
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Gone but not forgotten: 2001 Honda HRV; 1989 VW Polo C Mk2; 2000 Honda Civic VTi Aerodeck
; Cavalier SRi; Cavalier LX; 1971 Triumph Spitfire Mk3; 1963 Triumph Herald.