The sides were locked at 6-6 at halftime, the Vulcans going out to a 16-6 lead in the opening stages of the second spell.
The Bulldogs closed the gap to just 12-16 with 10 minutes to play but Faitala-Mariner's Vodafone Junior Warriors team-mate Albert Vete ensured victory with a late try.
The result lifted the Vulcans to sixth on the table.
At Mount Smart Stadium No 2, Auckland
Auckland Vulcans 22 (Raymond Faitala-Mariner, Agnatius Paasi, Atelea Nafetalai, Albert Vete tries; Agnatius Paasi 2 conversions; Sio Siua Taukeiaho penalty).
Canterbury-Bankstown Bulldogs 12 (Moses Mbye, Paul Carter tries; Jack Littlejohn 2 conversions).
Referee: Aaron Donald.